Offshore Crane Operator Handbook
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ECOCOPYPRINTOffshore Crane Operator Handbook
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ECOCOPYPRINT5.0 M me _ When distance x weights are equal balance (in theory) 5x40=200 | 40 kg 10x20=200 20 ko 5.0 M 10.0 M cise 0 CRANE ON POINT OF TIPPING crane weight ~ 40 tonnes Abte y 3x40=120 10x12=120 10.0 M i + C of G of C of G of erane no load crane and load fue 1 fer rae Oper Handbook foro 8 Pee No 24 LEVERAGE LOAD MOMENTS A load moment is a force created by a load applied through a distance from a pivot point (Fulcrum). Load (force) x distance (from the fulcrum) equals load moment. In effect a crane is a balance of loads through a fulerum point, (cranes fulcrum is the centre pin). Figure 9 The loads of 20Kg are equidistant from the fulcrum with a resultant moment of 20 x5 = 100 Kg metres both sides of fulcrum result - the loads are in balance Figure 10 40 Kg x 5 metres = 20Kg x 10 metres 200 Kg metres = 200 Kg metres result - again the moments are equal even though loads and distances not equal Figure 11 this principle can be applied to cranes left hand side 40 tonnes x 3 metres = 120 tonnes metres right hand side 12 tonnes x 10 metres = 120 tonnes metres result - the crane is in balance Mobile cranes operate under the principle of stability, with the centre of gravity moving within the stability base. If the centre of gravity stays within the stability base the crane is stable Offshore cranes operate under different principles relying mostly on the structural strength of the crane and components. Therefore, in conclusion, a load moment when applied to cranes is a load multiplied by a distance (radius) plus other forces. NOTE - This explanation is very basic, in reality there would be other forces to take into effect when calculating out the load moment and that is beyond the scope of this course. Offshore Crane Opera Harook Rov 0% Apal 06 Page No 25 BASIC MECHANICAL PRINCIPLES Mechanical advantage by "Reeving’ Cranes use winches and wire ropes in the hoist and sometimes boom hoist systems. These are used with pulleys or sheaves. Any crane will only have a certain amount of power to operate all its functions. When all the power is "used up", then the crane will stop. Power is needed to lift loads and to raise the boom. A lesser amount is needed to swing the crane. When power for the hoist and boom hoist are considered, the power available is enough to achieve the single line pull of the winch Thats, the load which the winch can lift using only one part of line (rope) between the winch and the load. Diesel engine cranes usually have fairly low single line pull. Even a 100 ton crane will not lift more then 10 to 12 tons (approximately) using only one part of line. If the winch has to lift more than its single line pull then a method has to be found to increase the load using the same fixed amount of power. With cranes, the system used is called reeving, using more then one sheave. By using this method the load that can be lifted is increased but speed and distance are reduced. Line speed is the speed at which the winch pulls the rope. On single part line the hook speed is the same as the line speed. ‘As more parts of line are used the hook speed is reduced. ‘When using reeving systems there is always a loss of load due to friction of the rope around sheaves and in sheave bearings or bushes. NOTE - Friction loss is not taken into account in this explanation. Offhore Grae Operator Handbook er 01 Ape 06 Page No 25 REEVING Winch with single line pull of 4 tons one sheave two sheaves é single part f t 2 part line "i line ¢ ‘ & \ : ANCHOR- { 4 é . y2 4 tons 8 tons three sheaves 3 part line six sheaves 6 part line ii 24 tons} HOOK SPEED=Line speed divided by parts of line Figure 12 Cftanore Ceane Operator Hansbook Rev1 Aprio6 Page No 27 MECHANICAL PRINCIPLES WINCHES It has been said that winches are machines, or devices, used for “pulling” wire rope. Winches also have to "spoo!” or store the rope. ( When a hook or boom is at a low point then most of the rope may be off" the winch. When the hook or boom is at a high point, then the rope will be “on” the winch or the winch may be "full", This is important because as the winch is lifting, or lowering it changes in size or diameter. The root diameter of a winch is the diameter of the drum without a rope on it. The first layer of rope is the bottom layer. The last layer of rope is the top layer. If the same amount of power is used and the winch turns at the same speed, the line speed changes and when it does, the line pull changes also. LINE SPEED AND LINE PULL ROOT LAME TER fem FIRST LAYER. | LAST LAYER Hook at low point Hook at high point Rope SEF winch Rope ON winch Smaller diameter Larger diameter Line SPEED slower Line SPEED faster Line PULL higher Line PULL less The same principle applies to boom hoist wineh TYPICAL HYDRAULIC CRANE HOIST WINCH SINGLE LINE PERFORMANCE CAYER LINE PULL | LINE SPEED Rose TONNE MIEGES Pre MIN 7 735 ToT z Tie 137 5 eat 216 4 5236 236 3 3230 236 é soit S78 $ 27S 238 3 aoat STs NEVER exceed the rated line pull of a winch. This Is especial ly important with platform and rig cranes. which use long ropes- It is possible that « load may be Ilfted from a supply vessel, bUt cannot be lifted to deck level. . If a crane nas a_two speed lifting system +. it will usually nave different capacities im Aigh and low speeds. Figure 13 (hove Grane Operate Handbook Rev0% Ap 08 Page 25, CRANE TYPES ‘There are basically two groups of boom (jib) cranes. 1. Those machines which are designed with lift crane duties as their main job. Cranes In this group will usually be hydraulic machines. They may be telescopic, fixed or lattice boom cranes. 2. The second group of cranes are those that are designed or developed from machines that can perform many jobs by using different attachments. For example, excavation (back-hoe, or face shovel), piling rigs, even rotary drilling, Crane duties are only one of the jobs which they can perform, by using a boom as an attachment and the boom will usually be of lattice construction. These other duties are best done with a different form of power train and these cranes are known as mechanical machines (sometimes called friction drive or excavator type). Whatever the type of crane, it will need three systems to operate its functions. SYSTEMS BASIC SYSTEMS FUNCTIONS ELECTRIC MOTOR HYDRAULIC DIESEL ENGINE MECHANICAL, FIRS SSS (Ser Er JATRANSIISSTON aoe * tients ——1 CONTROL, ‘SWING COUPLING PNEUMATIC cu eu ~ HYDRAULIC TORQUE ELECTRIC CONVERTER | MANUAL, Figure 14 (chore Crane Operator Handback Reva Apnias Pogo No 29 1. The crane will need a power system. The majority of boom cranes use diesel engines. Others can use electric motors. 2. The power from the engine has to be sent where it is needed and this is done by the transmission system. 3. The crane will also need a control system. All cranes need rotating or turning movement to operate the winches and swing. With a diesel engine, the movement is already present from the engines crankshaft. MECHANICAL transmission passes on this movement from one part to another without changing it. Speed and direction can be changed using gears or chain drives but the rotation is continuous. HYDRAULIC transmission is different. In this case the engines movement has to be changed into a flow of oil by using the engine to drive a pump or pumps. This flow of oil is then directed to where it is needed and is changed back into turning movement at the winch or swing gear by using hydraulic motors. ‘When this happens pressure begins to rise in the system until there is enough to overcome the resistance or load on the winch or swing gear. There are also a number of diesel-electric cranes manufactured. Machines of this type use a diesel engine to drive a generator and the power produced by this is used to drive elect motors in the cranes functions. The operator also has to control speed and direction of the cranejs functions and to do this a control system is necessary. On mechanical cranes the control system is the method used to engage clutches and brakes and this may be done mechanically using linkages or by using compressed air (pneumatic). ‘Some machines use hydraulic pressure to control the cranes functions (not to be confused with hydraulic transmission), Most mechanical machines use a combination of mechanical linkages (for brakes) and some form of pressure to operate clutches. Sometimes electric switches are used to operate certain safety devices that can stop the cranes functions and these are part of the control system. The control system on hydraulic machines is the method by which the oil is directed to the functions. It is very difficult to control large flows of oil and high pressures manually and the control system on cranes that use high pressures will usually include a system to reduce very sudden increases in speed or pressure. Again certain safety devices may be included in the control system. Many hydraulic cranes use low pressure hydraulic control. Others use pneumatic control or electric control. There are machines which use a combination of all three. Chore Crane Operator Handbook Rev 0% Apa 98 Page No 20 MECHANICAL TRANSMISSION The example shown is known as @ single drive system. TECHNICAL POWER TRAIN HOW ROTATION IS TRANSMITTED S) BOOM HOIST GC | POWER LOAD -s FRONT ORUM SHAFT- LOWERING SHAFT ZS (LID | ay) | \ iN RU (Fi Saran /S * ORUM SHAFT Seu MAIN ORIVE SHAFT oraue converter! / cuuren + @ @—auurenes cen onives ©_O~—crain onives Figure 15 There is only one connection between the engine and the function shafts, which is the primary drive chain. The movements for the entire cranes (machines) functions are taken from it and they are all connected together. If one shaft is stopped then all the others must also stop. (ttchore Crane Operator Handbook Rev Apeio6 Page No 31 If the engine is connected to the primary drive by a friction clutch then the engine will also stop if the shafts stop. A clutch is @ device which is used to connect two rotating parts or to connect something which is already turning to something that is required to turn. Some systems have a torque converter between the friction clutch and the primary drive. This is a device that provides a fluid drive between the engine and the rotating shafts. If @ torque converter is fitted then this will allow the engine to continue running even if the shafts are stopped, or "stalled". The converter also allows power to be applied smoothly and speed changes to be made gradually. Generally, the function clutch (boom, hoist or swing) is fixed to the shaft. The function is selected by engaging the clutch to the winch (or gear) that is not fixed to the shaft. Hoist brakes are usually manual and must be released and applied by the operator. Boom hoist brakes should always be automatic, that is released or applied by the movement of the boom hoist contro! lever. ‘Swing brakes are usually manual and with most cranes are used fo hold the machine, not to slow down movernent. NOTE These are general comments; all machines are not the same. The manufacturers information and instructions should be read and understood fully before operating any machine. The way in which hydraulic and mechanical cranes are operated is different. There are various actions that must be taken by the operator in order to keep the crane and hence load under control. These actions will be covered in the practical section of the course. Basically to retain good control the speed of the craners movements must be changed. With mechanical transmission, this means changing the speed of the engine because all the movements are connected to it. With hydraulic transmission, most manufacturers state that while the crane is working the engine should be run at high speed. This means that the speed of the craners movements is controlled by the movement of the control levers, not by changing engine speed. In other words, the crane is controlled by controlling the flow of oil through the control valve. (shore Crane Operator Hansbcok er D4 Ape 08 Pagee 22 YI Al CONTRO! Figure 16 shore Crane Opsrater Handbook ev 1 Agni 06 Pege no 39 PRINCIPLE OF HYDRAULIC ORIVES ROTARY OUTPUT (ROTATING SHAFTS) ZIM, \.0" PRESSURE ENGINE HYDRAULIC ORIVEN CYLINDER PUMP SHAFT Figure 17 (shore Grane Operator Handbock owt Apr 08 Page a 26 SIMPLE HYDRAULIC SYSTEM ( HOIST) rhydeaul te ‘oll flow ~ holst return [ine J rotor return Iine (P.ReV. open) ofl Flowlower-.. pressure relief. valve (hoist siide) -return line (controi volve neutral ) directional control Pressure ~s, valve 6 guag: pumps sing oft tine punp to | —-boom control vive holst Le A [S011 reservoir 8 oll strainers Hydraulic fluid 1s taken from the reservoir to the control valve. If the control is In neutral, the of! passes through it ond returns to the tank. When the lever Is moved to holst. the ol! Is directed to the winch motor pressure rises» and the winch turns. The fluid which has passed through the motor returns to the tank. The pressure relief valve (?.R.V.) is sat to the maximum safe working pressure for the system If the load Is too heavys(If It needs more then this prossure to lift i+) then the P.R.V. will open and the of! will return to the reservoir. The winch will not turn. Figure 18 Ofishore Grane Operator Handbook Rev 1 Age 06 Poge No 36 TORQUE CONVERTERS TORQUE is not easy to define without knowledge of mathematics. However, for the purpose of this course, an attempt will be made to keep things as simple as possible so that the crane operator will have a basic understanding of what the torque converter does where cranes are concerned, Basically, torque is the turning or twisting moment exerted by a force at a distance from the axle of rotation, In this case, the engine tums in one direction but the load wants to go down (gravity). The engine has to produce enough torque to raise the load otherwise it will stall or stop. Figure 19 Generally speaking diesel engines do not produce much torque at low speeds though some are better than others. A torque converter is usually used on cranes with diesel engines and mechanical transmissions. It performs two main functions: 1. to provide a fluid coupling, or drive between the engine and the transmission. This means that if the transmission is stalled or stopped, the engine will continue to run. Often a friction, "disconnect" clutch is used between the engine and the converter. 2 to multiply the incoming torque (from the engine) to a point where the resistance of the load is overcome. This of course, can be increased by increasing the engine speed A light load needing a low line pull will not need much increase and will rise quickly in relation to the speed of the engine. Aheavy load, requiring a high line pull will rise more slowly in relation to the engine speed. In other words, the converter output shaft will turn slower than the input (engine) shaft Orthore Crane Opeator Handcok Rev 01 Apri 06 Pane No 36 our sar (- Leap Le Figure 20 Torque multiplication is done hydraulically by changing or re-directing the flow of oil inside the converter. Torque converters also protect the engine from damage caused by shock loads and/or stalling. There are a number of different types of torque converters. The example shown is known as a single stage converter and itis widely used on cranes. It is supplied with oil from a tank by its own charging oll pump and the oil passes through an oil cooler before returning to the tank. When the engine is running and the clutch is engaged, the converter begins to turn and, as it turns, the charging pump supplies oil into the converter. The vanes of the pump direct this oil against the vanes of the turbine that begins to transmit torque to the output shaft. The vanes of the turbine also direct oil against the vanes of the stator. The stator is designed to "freewheel" in one direction, and “lock up" when oil from the turbine tries to turn it in the opposite direction, When this happens, the oil leaving the turbine is directed back to the pump by the vanes of the stator. This is how torque multiplication is achieved. ‘As the speed of the turbine (output shaft), nears the speed of the pump (engine) the need for torque multiplication decreases. The flow of oil inside the converter changes and acts on the opposite side of the stator, causing it to freewheel and the converter becomes a fluid coupling. Otfeore Crana Operate Handbook Rev0t Apeios Page to 37 This is possible because the stator is mounted on a one-way cam and roller clutch, This will be covered in the next section. OUTPUT SHAFT CONVERTER CHARGING ~ PuNe Lconverrer Hous ine Inside the converter housing ore the three main elemants. The convertor PUMP. which Is driven by the engine. The STATOR, which provides the TORQUE MULTIPLICATION. The TURBINE. which drives the OUTPUT SHAFT. Figure 21 There are other types of hydraulic torque converters. Some operate in distinct stages by changing the angle of the vanes. There are some that can be modulated, that is the output torque is controlled by the crane operator without changing the engine speed. While torque converters can be a great boon to crane operation they can, if not understood, become dangerous in some cases, Whatever the type, the manufacturers instructions (crane and converter) must be read and understood before operation commences. (Offshore Crane Operator Handtcok Rer01 Apa 06 Page No 28 ONE-WAY AND OVERRUNNING CLUTCHES There are a number of different types of one-way clutches that can be used on cranes. They are used for a variety of reasons, usually to control lowering speeds. Basically, they are designed to prevent a function from over-running or lowering faster than the shaft that provides the lowering direction. They can be used in torque converters to prevent the transmission from turning faster than the engine. Over-running clutches are often used in boom lowering systems on mechanical transmission cranes and sometimes in the winches of hydraulic cranes. Camiroller and sprag are the most commonly used types. SPRAG TYPE CLUTCH ROLLER TYPE CLUTCH | K | \ at / | ENGINE DRIVEN OUTER SHAFT ROLLER / | GEAR RACE ul ‘SPRING SPRAGS guTER RACE Figure 22 SPRAG CLUTCH (BOOM LOWERING) When the boom winch is stopped, the clutch shaft is stationary and the outer race idles in the direction of the arrow. When the boom is raised the clutch shaft tums in the direction of arrow 1 When the boom hoist brake is released to lower the boom the weight of the boom tums the clutch shaft in the direction of arrow 2. The sprags then lock-up and the clutch shaft that is connected to the boom winch cannot turn faster than the outer race that is controlled by the engine driven geer. Offshore Crane Operator Handooce Revot Apnias Page No 29, SPRAG TYPE BOOM LOWERING CLUTCH ENGINE, DRIVEN GEAR A BOOM HOIST WINCH GEAR c Figure 23 PRINCIPLE OF OPERATION Otehore Crane Operator Haneeae Rev Ap 6 Page 40 ROLLER CLUTCH This operates in similar fashion to the sprag clutch, In this case, if the outer race tries to turn faster than the shaft, the rollers will move up the ramps assisted by the springs. When this happens the inner and outer races become jammed together and the clutch locks-up. NOTE Some over-running clutches are oil filled and usually require special fluid. The manufacturerss instructions must be followed. TYPICAL PLANETARY LOAD LOWERING (P.L.L.) UNIT INTERNAL RING GEAR (OUTER FING) DRIVEN SHAFT — ‘SPIDER PLANET GEAR SUN GEAR SPROCKET AND CHAN ‘TOHOIsT WINCH DRUM (HELD BY HOIST BRAKE) ‘The SUN gears splined to the driven shatt The PLANET gears are held in position by the SPIDER which 's connected to the SPROCKET. ‘The SPROCKET is connected to the hoist drum by the CHAIN, When the PLANETARY BRAKE is OFF, and the HOIST brake is ON, the drive is passed to the INTERNAL RING GEAR which idies in the OPPOSITE direction to the DRIVEN shaft. When the PLANETARY BRAKE is applied, and the HOIST brake is released. The PLANET {gears (and SPIDER, and SPROCKET) MUST revolve around the SUN gear in the SAME direction as the driven shaft. Figure 24 Oahore Crane Operator Handbook Rev 0% Apri of Page No 41 DIESEL ENGINES The fundamental differences between diesel and petrol engines are the types of fuel used and the methods by which the fuels are ignited, The diesel engine has no spark plugs as do petrol engines; however some diesel engines have %glow plugs” to aid starting in cold weather. In a diesel engine the fuel is ignited by the heat of compression. In fact diesel engines are often referred to as Compression Ignition (C.I.) engines. Ignition takes place when the air compressed by the piston exceeds 1,000 °F and diesel oil is sprayed into the cylinder. ‘Speed and power are controlled by the amount of diesel oil sprayed into the cylinder. The amount of air is constant and the fuel-to-air ratio is not critical. There are two types of diesel engines: © Two Stroke © Four Stroke This is the correct terminology and means that it takes two strokes of the piston to complete the firing cycle on a two stroke engine and four strokes of the piston to complete the firing cycle on a four stroke engine. Two stroke diesel enc s must have air forced into the cylinders by means of a blower or super charger but a four stroke engine may be naturally aspirated or use a blower, super charger or turbo charger for extra power Cttnore Crane Operator Henbook Rov 04 Ape 06 Pageno «2 THE FOUR STROKE OLESEL ENGINE INTAKE COMPRESSION Figure 25 In this engine the complete firing cycle is accomplished in four strokes of the piston. On the first upstroke, the air is compressed raising the temperature to about 1,000 ° F, the point at which diesel fuel will ignite. Near the top of this stroke, diesel fuel is injected into the cylinder. By the time the piston reaches the top of the stroke and starts down again, the fuel is ignited and the expanding gases will power the piston down (second stroke) At the bottom of the power stroke, the exhaust valve opens and the rising piston will push out the spent gases (third stroke). At the top of this stroke, the exhaust valve will close and the inlet valve will open allowing air to be drawn into the cylinder by the descending piston, this is the fourth stroke of the piston to complete the cycle. Otshore Crane Operator Handbook Rev 0t Apr o6 Page No 43, THE TWO STROKE DIESEL ENGIN INTAKE COMPRESSION Figure 26 In this engine the complete firing cycle is accomplished in two strokes of the piston. As mentioned earlier, two stroke diesel engines require a supercharger to blow air into the cylinder and at the same time scavenge the exhaust gases. Air enters the cylinder through ports around the cylinder wall when the piston is at the bottom of its stroke. As the piston starts upwards it closes off the ports and starts compressing the trapped air. As the pressure rises so does the temperature and at about 1,000 ° F the fuel injected will ignite and power the piston down. Theoretically a two stroke engine should produce twice the horsepower of a four stroke engine with the same displacement but this is not so because the high temperatures produced inside the cylinders cannot be dissipated quickly enough. As a result, the temperatures must be kept lower and this means the energy produced by the buming fuel is reduced. In addition the power consumed in driving the supercharger amounts to about 25% of the engines horsepower, so in all there is very litle difference in horsepower between the two and four stroke engine. Ofehore Crane Operas Handbook Rev01 Apri 0 PagoNe 44 DIESEL FUELS Low speed diesel engines can operate on aimost any kind of liquid fuel from paraffin to heavy fuel oil Modem high speed diesel engines however, require a lighter fuel with a good ignition quality due to the short time interval available for combustion. Ignition quality is measured by an Index called cetane number, similer to an octane rating for petrol. Present high speed diesel engines require a cetane number of about 50, The cetane number of a fuel is the percentage of cetane by volume in a mixture of cetane and alpha-methyl-naphthalene. Cetane_has an excellent ignition quality and alpha-methyF-naphthalene hes a very poor ignition quality. ‘A fuel oil that does not have enough percentage of cetane will cause difficult cold starting and a rough and noisy operation. DIESEL FUEL-INJECTION SYSTEMS The main requirements of a diesel fuel-injection system are: Accurate metering, or measuring, of the fuel delivered for each power stroke must be the right amount for the engine load and exactly the same amount of fuel must be delivered to each oylinder of the engine. Proper timing means beginning the fuel injection at the required moment; this is absolutely essential in order to obtain maximum power from the fuel, good fuel economy, and clean burning combustion. Rate of fuel injection is the quantity of fuel injected into the combustion chamber in one degree of crank travel. If it is desired to lower the injection rate, a nozzle tip with smaller holes must be used in order to increase the duration of fuel Injection. ‘Atomization, or breaking up the fuel stream into a mist like spray, must conform to the type of combustion chamber. Some chambers require very fine atomization; others con operate with a coarse spray. Proper atomization of the fuel insures that each minute particle of fuel is surrounded by as much oxygen as required for combustion, Distribution of the fuel must be such that the fuel will penetrate to all parts of the combustion chamber where oxygen is available for combustion All mechanical-injection methods for diese! engines may be classified as follows: multi-pump injection system unit fuel-injection system distributor-type injection system common-rail, or pressure-time, injection system Bona (tshore Crane Operator Hansock Rev0' Apes Page No 45 DIESEL ENGINE GOVERNORS In the diesel engine, speed control is related to the amount of fuel injected into the engine because there is no way to control the amount of air taken into the engine. There are four basic types of governors:- 1. Load-limiting governors are designed to actually limit the load that an engine can take. 2. Variable speed governors are used quite often in crane operations. They will ‘maintain engine speed at any preset speed from idling to maximum rpm regardless of load changes. 3. Limiting speed governors limit only the minimum and maximum rpm of an engine. The speed between maximum and minimum is controlled manually. 4, Constant speed governors are used for generator applications to hold the engine at the some rpm regardless of load. OVERSPEED GOVERNORS Overspeed governors and trips are employed as safety devices to protect engines from damage due to overspeeding from any cause. With an engine equipped with a regular speed governor, an overspeed governor will function in the event of failure of the regular governor. Overspeed trips usually bring an engine to a full stop by cutting off all fuel or air supply to the engine. This method of engine protection is often found on offshore installations where a possibility of natural gas inhalation exists. LUBRICATION SYSTEMS A large diesel engine consists of many moving parts designed to give thousands of hours of trouble-free service, all of these parts depend on a thin film of oil for protection against the destructive action of metal-to-metal friction. The amount of oil actually forming the oil film essential to the life of the engine may be only a small percentage of the oil in the crankcase when the engine is running. A large reserve of ail is provided which helps cooling and allows a reasonably long period between cil changes. The basic functions of lubricating oil in a diesel engine are: * to provide a film between moving parts to prevent metal-to-metal friction and reduce wear * to serve as an intimate cooling medium to reach heated areas more directly than cooling water eg on the under side of a piston or the moving parts of a bearing * to form a pressure seal between the piston and cylinder walls and to act as a cleaning agent to remove gummy compounds that are the products of combustion and heat (tore Crane Operatar Handbook Rov 0% Apa 06 Pagenio 46 FILTERS Both diesel and petrol engines are fitted with oil filters in the lubrication system. These filters clean the oil of small particles of metal and dirt When replacing these filters the correct type and size must be used. Many filters look the some on the outside, but differ 2 great deal on the inside. Should a fuel filter be installed instead of an oil filter, the smaller holes in the fuel fiter will cause an excessive amount of resistance to the thick lubricating oil. As a result, much of the oil would flow around the filter and no filtering would take place. As a safety feature, all oil filters are equipped with a relief valve This valve serves as a bypass so that the oil supply to the engine will not be interrupted even if the filters clog. This relief valve is usually Set to actuate at about 20 p.si. Should a filter become clogged to the point that it puts up more than 20 p.s.i resistance, the valve will automatically open to allow passage of unfiltered oil. Of course the unfiltered and dirty oil can cause engine damage but not to the extent of a total lack of oil One word of caution An operator can no longer take a sample of oil, put it on his finger and decide if the oil needs changing due to the colour of the oil. The new high detergent oils will be derk in colour almost immediately after they are put into service. The word detergent in the designation of oil indicates that there is some type of cleaning action taking place inside the engine. The oil has chemicals in it that serve to cleanse and break down carbon deposits. As this cleaning action takes place, the dark particles of carbon are cartied by the oil into the filter system. ‘The particles that are large enough to cause damage to the moving parts of an engine by breaking through the oil film are taken out by the filters, but small particles will remain in the oil to make it darker coloured. COOLING SYSTEMS About one-third of the heat generated by the combustion of fuel within a diesel engine is converted into mechanical energy. ‘The other two-thirds must be dissipated by one means or another. Half of this unused heat (one third of the total) is ejected by the engine exhaust or lost to the atmosphere by direct radiation. The other third that is wasted must be absorbed by the cooling system. Dissipation of this heat is of prime importance. Normal combustion of fuel in an engine produces peak temperatures between 3,600° F and 500° F. A large portion is transferred to the cylinder walls and head, pistons and valves. Unless this excess heat is carried away, the engine will be damaged. A cooling system must be provided not only to prevent damage to vital parts of the engine but the temperature of the components must be maintained within certain limits in order to obtain maximum performance from the engine. Except on very large engines the radiator is probably the most common method used to cool an engine's coolant. A radiator is actually a fluid-to-air heat exchanger, in that heat in the coolant is transferred to the air that passes through the radiator. The air is forced through the radiator by means of a fan, a good flow of air through the radiator is essential for good heat transfer. A good flow of coolant is also necessary to carry heat away from the engine, a pump is provided for this purpose. Offshore rane Operator Haeook Rev 01 Agr 06 Pogeo 47 HEAT EXCHANGERS A heat exchanger cooling system, usually found on larger marine engines, uses a bundle of tubes inside a closed shell. Raw water is passed over the tubes and picks up heat from the engine coolant inside One of the most neglected items of the cooling system, either with a radiator or a heat exchanger, is the quality of the water. Poor quality water can cause the engine block to corrode to the point of destruction. Corrosion can be prevented by treating the cooling weter with @ corrosion inhibitor. Most anti-freeze contains such an inhibitor and the manufacturers instructions should be consulted for the correct mixture for particular location of the engine. AIR CLEANERS Ithas already been said that the filters in the oil lubrication system must be maintained in a clean condition to minimise engine wear due to oil contamination Small particles of dirt and foreign objects could also enter the engine through the air intake, unless the incoming air is property filtered. The size of an air cleaner is important whether the cleaner is an oil bath, dry or paper element type. If an air cleaner is too small, maintenance intervals will be frequent and in the case of the oil bath type, oil could be drawn into the engine resulting in an overspeed occurrence. On the other hand if the air cleaner is too large, its efficiency will be poor and dirt may be allowed to enter the engine. STARTING SYSTEMS Electric starters are probably the most common type of starter motor. Most cranes have an electrical circuit of either 12 or 24 volts sufficient to operate a starter motor. The electric current drawn from the batteries when the starter motor is operated may be as high as 500 amps or more therefore heavy cables are required to carry the large current. An electric starting system is dangerous if not operated properly. A storage battery is necessary to provide current for the starter motor. Care should be taken to assure that a direct connection between the two posts on the battery cannot occur or an explosion could take place. AIR STARTER MOTORS Air starter motors function in the same way as electric starters except compressed air is employed instead of electricity. ‘This method requires air pressure of 100 to 160 p.s.i to operate the motor. (ftehare Crane Operator Hancbosk Fev01 Apri Page No «3 TURBO CHARGERS AND SUPERCHARGERS All two stroke engines employ some type of compressor to force air into the engines, thereby pushing out the exhaust gases after combustion. The most common arrangement is the roots-blower. BLOWER OPERATION Figure 27 The two rotors are geared together and so rotate in opposite directions at equal speeds within the casing. There is a small clearance between the rotors and the casing and this type of compressor will deliver a relatively large quantity of air to an engine with as much as 6 p.s.i pressure. Ofshore Crane Operator Handbook Rev Agr 6 Page No 40 TYPICAL TURBO-CHARGER Figure 28 A turbocharger is a simple mechanical device consisting of a compressor housing a centre housing, a turbine housing and a turbine wheel, with a shaft and compressor wheel. The purpose of a turbocharger is to pump more air into the engine than would be obtained by natural aspiration. It serves the same purpose as the geared blower of a two stroke engine, ‘The design of the compressor wheel, the impeller of the turbocharger and its housing causes air to be compressed as the wheel turns at high speed. The rotational speed of the modern turbocharger can be as high as 60,000 to 100,000 rpm, depending on engine size and type of turbocharger. The very high speed of the rotating assembly requires a constant flow of lubricating oil from the oil pump. Turbochargers continue to run at high speed for some time after the engine speed is reduced or the engine is stopped therefore a "slow down” period should be allowed to ensure continuous lubrication of the turbocharger assembly. Chore rane Operator Handbook For 01 Apri 08 Paseo 50 SAFETY DEVICES Ofishove rane Operate! Handbook Rev 04 Apr 06 Page No St SAFETY DEVICES ‘There are a number of safety devices that can be fitted to cranes. Limit switches may be fitted to the crane’s hoist, boom hoist and sometimes swing functions. Hoist limit switch (sometimes called anti-two block) may be fitted to limit the hook travel. Usually these are installed to prevent the hook being pulled into the boom head pulleys. ‘Sometimes limit switches are fitted to prevent the hook being lowered too far. The limits may be activated by a "chandelier" or bar type switch at the boom head or tip. Alternatively a spindle or geared switch at the hoist winch may be used. These must be set by the operator when boom length, or parts of line, (reeving) is changed. HOIST LIMIT SWITCHES “CHANDELIER” TYPE Operates when hook lifts hanging weight SPINOLE/GEAR SWITCH + Oriven by winch THREADED SPINDLE Figure 29 ‘hore Crane Operator Hentbook Rev 01 Apa 06 Pagoo 52 Boom limit switchisystem may be fitted to prevent the boom being lifted beyond its maximum angle (minimum radius) and is sometimes used to limit the minimum angle (maximum radius). ‘System may be mechanical linkages which return the boom hoist control to neutral, or electrical, hydraulic, or pneumatic switches which again neutralise the boom hoist function. TYPICAL BOOM (UPPER) LIMIT SWITCH ~~BO0M FOOT Figure 30 SPINDLE/GEAR_ SWITCH Fa by winch THREADED SPINOLE Figure 34 OWtenore Crane Operator Haetook Rev} Apri 96 Pege No 63 Boom Angle Limiter & Figure 32 National Cranes utlise a different means of stopping the movement of the boom at minimum radius on some crane models. Their system returns the control lever to the neutral position but if the crane operator continues to apply pressure to lever limit system can be Cffenore Crane Operator Handbook Rev 0% Apa 06 Page No 56 ‘Swing (slew) limits are sometimes filled to prevent cranes working over hazardous areas or close to power lines. Whatever limit systems are fitted to a crane they should never be totally relied upon. A good operator will always know the position of his boom and hooks, Limits should be regarded as being there to prevent accidental damage. Always approach any limit with caution and remember that they may not work Pawls are usually fitted to cranes to allow a shaft or winch to rotate in one direction but not the other. The most common use is in the boom hoist where the pawl will allow the boom to be raised, but not lowered, ifit is engaged. ‘Sometimes pawis are engaged or disengaged automatically by movement of the control lever. Others are set or released manually by the operator. As a general rule, the paw! should be engaged when raising the boom, especially at low angles. It should also be used when handling heavy loads and when the crane is parked, If the crane is used on heavy duty work, grab, or piling for example, the pawl should also be set (engaged). This relieves the strain of shock loading on the boom hoist brake and gear. NOTE Occasionally if crane is at minimum radius it may be necessary to over-ride upper boom limit to release Boom Pawl TYPICAL BOOM HOIST PAWL OPERATOR SET AND RELEASE CABLE TO CAB” Figure 33 Locks and Dogs are used to prevent movement in any direction. Dogs are used in the travel gear of crawler cranes to lock the tracks so that movement is not possible. Swing locks, sometimes called cab-locks, are used to lock the upper works (cab) to the lower works (truck or crawlers) so that swing is not possible. Swing locks should never be used while the upper works are moving. They should be used when travelling the crane and when it is parked, Otishore Crane Operator Handbook Rev or asi os Page No S5 GOP - GROSS OVERLOAD/OVERMOMENT PROTECTION SYSTEM UPS - ULTIMATE PROTECTION SYSTEM These are safety systems fitted to prevent a gross overload to the crane structure. Manufacturers utilise different ways of achieving this aim, so it is very important that the crane operator understands the system fitted to a particular crane. ‘The main features of any GOP(S)/UPS are: Fully automatic operation requiring no crane operator action High response speed Total independence from any crane system (normally) Safe indication of true overload/overmoment before producing load release Stothert & Pitt originally referred to their system as UPS (Ultimate Protection System). The system activates in 2 stages: * Stage 1 responds to a moderate overload activating a ram fitted into boom reeving and also allowing movement of the crane hook. This stage is recoverable. + Stage 2 respondsiactivates to a severe overload and allows a controlled release of hoist rope. Gop. SYSTEM Figure 34 Cffenore Crane Operator Handbook Revo Aen os Page No 56 SCHEMATIC Stothert & Pitt Ultimate Protection System Nitrogen precharge pressure ensures sensing unit i fly retracted unless won Ss Lain ROPES: z 77 8 we A x netzase SxLNCER PRESsuRIseD TaN Encore ent ceria ‘ahr we m Sod Pressure swiros L~ Connect lene eid to Gy NM thereene yeas te oermorent sree x FT| aa a winch brakes aight tension mode Into high spec ae Lond novel baer pays fut under lignt tansion Figure 35 Offre Crane Opeater Hancock Fev01 Apr o6 Page No 57 Other manufacturers utilise different ways of achieving the same purpose. ‘Some systems are fitted to the main hoist winch and are controlled by the R.C.I. Rated Capacity Indicator activating at 150% of Static S.W.L Other systems operate in a similar manner but overload is sensed from the load sensor fitted into the boom winch, activating a release of the main hoist winch. ‘Ata force equal to 150% of SWL at the cup springs, the cup spring loaded piston operates the hydraulic valve. * The valve opens and the feed pressure can release the disc brakes for main- or aux hoist motion (depending on the one selected), * The same pressure acts/activates another vaive and limits the pressure in the hoisting system. + In this way the hoist rope is released and the crane protected from extreme overload cup spring loads piston hydraulic vaive oven transduoer Figure 36 Liebherr GOPS Care Crane Operatr Handbook Ror 1 Apel 08 Page No 58 CONSTANT TENSION, WAVE/HEAVE COMPENSATION, WAVE FOLLOWING Again manufacturers may have their own name/designation for this system but, whatever it is referred to, the aim is to decreaseleliminate any dynamic loading effects from the crane. Even though the means of operation may differ they all attempt to achieve the same effect, which is to apply a light tension to the hoist line with the winch paying in or out in synchronous motion with the supply vessel deck. As systems can differ in the final activation of lift-off of load, it is therefore imperative that crane operators fully understand the specific system fitted to a crane. EMERGENCY LOAD/HOOK RELEASE This is a safety system filled to a crane whereby if the hookiload gets stuck/eaught on the supply vessel, by activating the push button (normally coloured YELLOW) the brakes on the hoist drum are released andior the pressure on the hoist winch is limited. This protects the crane systems from overloading because the rope can be spooled off the winch (in a controlled manner due to pressure on winch). ‘As systems do tend to differ between manufacturers it is important that the crane operator understands fully the particular system fitted to the crane, EMERGENCY (ENGINE/POWER) SHUTDOWN Emergency shutdown of prime mover is normally activated by stay put push buttons (normally coloured RED). These shutdown butions should not be used to shutdown crane in normal use. EMERGENCY NO POWER OPERATIONS. Manufacturers can utilise different means of operation of the crane if it has no external power ie if prime mover fails to operate. Some manufacturers use hand pumps to release the boom and or hoist brakes to enable load to be landed safely. (On the slew, again the brakes are released but an external means of turning/rotating the crane must be used. Other manufacturers can fit electric motors to diesel engine cranes to enable motions to be carried out. Again it is the duty of the crane operator to fully understand the system fitted to the crane and be able to put it into practice. ROPE SPEED INDICATOR (RSI) Some cranes are fitted with a rope speed indicator that can display the speed al which the rope spools on and off the winch, along with the length of rope actually off the winch. Mipeg do supply an option on 2000 model for a RS! that can also incorporate the hoist limits, Otthore Crane Operator Handbook Rev04 Apnto¢ Pope No 59 tthore Grane Operetar Handbook er 01 Aon 06 Pagoo 80 SAFE WORKING LOADS Offshore Crane Oparator Handoece Rev 01 Age 06 Page No 81 RADIUS AND BOOM ANGLE The load that any boom type crane can lift will depend on a measurement which is known as radius (half the diameter) This is the distance from the centre line of rotation to the vertical load or hook line. The centre line of rotation is the very centre of the swing (slew) joint (usually the centre pin). It never moves in relation to the crane. The vertical load (hook) line is the line drawn from the boom head, straight downwards. This may be the centre of the main hoist sheaves, if more than one part of line is being used, or the outside edge of the pulley if a single part line is used. Radius of course, changes as the boom is raised or lowered Cranes also have a tail radius or tail swing. This is the furthest projection behind the centre line of rotation. CENTRE LINE OF ROTATION . ——BOME LENGTH Figure 37 Oetore Crane Operator Handbook er 01 Aon 08 Page No 62 Any boom crane will have minimum radius, and a maximum radius. These will depend upon the length of the boom. in Radlas_ "Max Load” Max Radius - tn Load Figure 38 Except in special cases, maximum radius will not be greater than the length of the boom. Boom length is measured from the boom foot pins to the boom head sheave shaft, (that carries the main hoist sheaves) Other attachments are treated separately, eg fly jib or jib extensions. This is important, as maximum radius for the attachment will usually be the same as maximum radius for the main boom. If an attachment is used to extend the boom length, the boom will have two different positions for maximum radius, ane for each of the hooks. NOTE Maximum radius is often less than the main boom length 800M PosiTion POR Maxi“tun — Raolus or rey aia __ MAxIMUM AADIUS BOTH. (SAME ASBGOM LENGTH) G SHISHOOK OUT OF RADIUS Figure 39 ffnore Crane Operate Handbone Fev 1 Apr 05 The most common way for a crane operator to find radius is by reading a radius that is fitted to the crane. These may be in various forms. icator Some are part of a Rated Capacity Indicator (RCI) sometimes still referred to as an Automatic Safe Load Indicator (ASLI) and these are dealt with in another section The simplest form of radius indicator is in the form of @ quadrant (a quarter of a circle) shaped scale, fixed to the boom. A weighted pointer, remaining in the same position by gravity, will indicate the radius of the hook in any boom position. In other words as the boom moves the scale also moves, but the pointer remains static. Radius indicators are often calibrated to show the load that can be lifted at any particular radius. They then become known as Load Radius Indicators (LRI). TYPE-HLC=35 SCALE: - ---——- 35 FT BOOM | RADIUS] LOAD : FEET | TONS 40_|_19.2 t2__| 16-7 ts | 11.65 -PIVOT 20; _Bat® 2s | 5.0 Ne 30 | 3.9 UNT ING. é SLOTTED FOR 35 | 3.15 ADJUSTMENT ay Boom” Figure 40 The scales on load radius indicators are interchangeable and the correct scale for the boom length must be fitted. If the boom length is changed, the scale must be changed. This is also true for any attachments fitted to boom. The quadrant can usually be adjusted by measuring a given radius on the ground exactly and placing the hook over the mark. The indicator can then be set accordingly to that radius. NOTE Radius Indicators are only a guide. Before lifting any load approaching the maximum for any radius, the distance should be measured. Offenore Crane Operate Handscole Rov01 Aon 08 Page No 64 BOOM ANGLE Many manufacturers, especially those from the United States, use boom angle to find radius. In these cases, a boom angle indicator is used. Again, it is a simple device similar to a radius indicator but is calibrated in degrees to show the angle of the boom in relation to the ground or horizontal (0°). Boom angle is usually measured in degrees from horizontal upwards. However, boom angle indication is sometimes used, when the exact boom length is known. For example, when the boom is fully extended and/or if a fly jib is fitted. Figure 41 tfshre Crane Operator Handiock Rev 01 Asn 06 Page Ne 65 RANGE DIAGRAM A Range Diagram is a diagram/graph that is used to convert boom angle to radius or vice- versa, (RADIUS) Figure 42 EXAMPLES ‘+ With a boom Length of 65 feet (line 1, Boom Arc) and a radius of 60 feet, (line 2, Vertical Hook the boom sits at an angle of approximately 27-28 °. (Line 3, drawn from Foot pins to intersection of line 1 & line 2, extended out to read Boom Angle) * Alternatively, for a boom angle of 27-28 ° with a 65 feet boom, the radius can be read as 60 feet. (shore Crane Operator Handbook Rev Apri ese No 66 SAFE WORKING LOADS (SWL) The SWL (safe working load) of a boom crane is the load that the crane can lift safely under any conditions (combination) of boom length and radius If either of these is changed then the SWL will be affected Safe working loads are also known as * Duties © Capacities «Ratings « Rated loads The crane operator can find the information he needs on the SWL Chart (Duties chart etc) for that machine. CHARTS SHOULD BE IN ALL CRANE CABS Some charts may appear quite simple, while others can be quite complicated so the notes on the chart are important. Basically, everything that is attached to the boom is considered to be part of the load. This includes hooks, slings, any attachments, fly jibs etc and, of course, the load being lifted, Mobile cranes are rated on stability, or stability and structural strength, They also have a safety margin ‘As a general rule, this safety margin will be 25% or more which means that if the load on the ‘SWL chart is increased by 25%, the crane will still remain stable, and strong enough. This safely margin is designed into the crane by its manufacturer. This should not be confused with test loads, these will be explained later. The crane operator should never exceed the loads set out on the SWL chart To find radius and load, the operator must now look at two sources. The indicator itself, and the relevant capacity chart (or part of a chart) He must know the length of the boom. The crane must not lift loads outside the working range. The only time the boom may be lowered below the minimum boom angle, or outside maximum radius is when it is being brought down to rest, never with a load. Ottehore Crane Operator Handbock Rev 1 Agrt 06 Page No 67 / MER FO waza soon / WET appa. 3611 sf | | / | \ 4 300M ANSLE 1 Z tT BOM ANOLE (DEPENDS UPON LC : ‘LENGTH = SO AHORIZONTALD . antes “ ¢ Figure 43, LIFTING CAPACITY CHART — UNIT MARINER MOD 280-H TORR RTOABLE GROSS LEA TH FOUN Tics a Beconcnce arRSCTURAL SAPETY FACTORS OF AMEN PETROLELM INSTETTUTE (S972), ABS UF CART nase ‘asa ALOABLE EON LENGTH FOR OFESHORE SERMOE LET TO 9 PT {Busey 7 sone uurstions ans rota Bon Uwe A RVARABLE, LOAD ‘BOOM ANGLES ABOVE HORIZONTAL (TOP FIGURE) ADIs LEMTING CAPACETY IN POUNDS (SOTTOM FIGURE) | weeer [ LENGTH OF BOOM TN. [3a as a ese a 1 | ear 56,600 is] 7eas" Tee | Tre | 788 | Tae | | 2730 4osco_| 36050 | 35.600 | 33,100 wf sir [zeae | sear | 77 44370. 37000 _| 34500 | 32.000 | 29950 [Stas ‘cara | corse [00 | 7orar 35420 337e0_| 3ia0_| 23200 | 27,350 ao acer Srey | eis | ear | ease 29,350 7a70_| 27200 | 25,700 | 2420 [ase Seno" | eror 24,960 zz950_| a Sta) S80 | 20930 | 20760 | 20,800 | 19,470 = ese] anor | aca | S09 i630 | 19.190 | 16.00 | 17,300 3 aise [sear] asa | anise te200 | ios | 15.960 | 15,660 = aeas" | 30s” 3736" i470 | $2,250 | 14,090 w ious" | oa 2820 | 12,620 11,390 7 | = | wo | QUIET WIGHTS | MAIN HOIST BLO OO LRS AUD HOIST HOORWETGHT 900 BS Figure 44 BLOCK WEIGHTS ARE FOR ILLUSTRATIVE PURPOSES ONLY ‘Otthore Crane Operator Handbook Rev 01 Apr Pape No 68 STATIC AND DYNAMIC LOADS The crane operator should understand the terms Static” and Sdynamic” where loads and conditions are concerned, A static load on a crane means that the effect of the load on the machine never becomes greater than the weight of the load. ‘A dynamic load is one where the effect of the load on the crane is more than the actual weight of the load. This can happen for a variety of reasons: + Sudden acceleration in the hoist or boom hoist systems can create dynamic loading Swinging loads, in any direction, will also increase the effect of the load on the machine and in addition directional forces come into play * Loads that are lowered quickly and stopped abruptly will also lead to dynamic loading The most common cause of this potentially dangerous situation is when the load comes onto the crane suddenly and in the offshore environment very often creates conditions that make the avoidance of shock or dynamic loading very difficult. Basically, slings should be brought under tension as slowly as possible and high speeds used to clear the vessel after the load is completely on the crane. In severe weather conditions, the operator must attempt to coincide the hoisting of the load with the upward movement of the ship, or when it is at its highest point of movement, never while the load is moving downward. If this happens, the speed of the hoist line upward and the load downward can combine to produce severe shock loading and dynamically increase the load by up to three times. Damage caused by shock loading may not be immediately visible but monitoring and experience have shown that the cumulative effects can and do lead to serious faults in both the structural and mechanical components of the crane. If the crane is fitted with a heave compensator, or constant tension device, this makes the avoidance of shock loading easier. However, these systems must be fully understood and the crane operator must be fully conversant with the system fitted to the crane and have practised using the system in calm/moderate conditions before using in severe weather conditions, Wind can aiso be said to be a dynamic condition because it is another force acting on the crane and load. The wind creates pressure on everything in its path and this is important wherethe boom and load are considered. Figure 45 Cichore Crane Operator Hancock ev 01 Age 08 Page No 69 LIMITATIONS OF STRENGTH, SPEED AND POWER Cranes are machines that are designed to lift loads. They are subject to limitations and these may be structural or mechanical. Structural limitations are based on the loads that the crane can lift safely without causing damage to any of its structural or load bearing components. These are usually the loads which appear on the capacity charts and may be given for either static and/or dynamic conditions. Some manufacturers give static loads only and leave it to the crane operator to reduce these loads according to conditions. More commonly in the UK and European waters, dynamic capacities are given and these will normally result in a reduction of the weight of the load lifted as conditions of wind and waves increase in severity. To simplify matters, the term 3sea state” is used (an altemative is to give SWH the Significant Wave Height.) Sea state is given in numbers and is the result of a combination of factors that affect sea conditions. These include wind speed, wave height, wave distance, water depth, tide etc. Sea state should not be confused with the term State of seag given in some weather information (see chart). The following table is a guide to sea states in different conditions of wind speed, and probable wave heights. Probable Beaufort Wave Height Scale Wind Speed Wind Speed Sea State (metres) (force) (knots) (mph) 0 0 0 O04 Ont 4 0.1 2 46 47 23, 1.0) 4 11-16 13-18 5/6 3 6 22-27 25-31 r 4 8 34-40 39-46 Figure 46 This is a guide only; actual wave heights may be much greater, with differing local factors. There is no definite rule that is used to determine safe dynamic loads. Some makers give a blanket reduction throughout the range of capacities. Others take into account the changing forces in the boom at different boom angles and this may result in heavier loads being safer to lift at greater radii, than close to the crane. Whatever the method used, the dynamic load capabilty of the crane will never be as high as the static load capability from the structural point of view. Structural components include the pedestal, slew bearing, machinery bed and intemal framework. The "A" frame and slewing column (or live mast) are also structural parts, along with the boom and any attachments. Boom pendant ropes are structural and crane running ropes, hoist and boom hoist, have structural and mechanical applications. NOTE Whichever method is used to calculate static or dynamic loadings it is the respon: and legal obligation of the crane operator to adjust and! or configure the crane safety systems to suit the prevalent operating conditions. Otishore Crane Operator Hancbook Reet Apri o6 Page No 70 TYPICAL SEA-STATE LOAD RADIUS CURVE CHART TONS TTT AT rE Sea st|0-Bto 4 a 3 20 7 “| LE Sea st 66 - BIS 4 _ Sea st./7 - BLB 7 to | Er 4 oeitdii ti io 0 10 20 30 40m re 0 50 100 FEET Figure 47 Ofihore Crane Operator Hancock Rev 04 Aon 6 Page No 71 LIEBHERR 90 TONNE CRANE BOS 90/950 PERMISSIBLE LOAD TABLE (3 FALL MODE) coca. MAXIMUM PERMISSIBLE LOAD wmeraes | PLATFORM BOAT LIFTS @ SIGNIFICANT WAVE HEIGHTS (HS) oeoxroveck | oeuces | voMeTnes | vawenes [powerees [saves 76 nates| FT soem |BTisotere| Rsoione| Laraomed Toasted has ors as. [goo - [Blo Eloso gla lala iehes + aes [Ele Sraso [Bisco |B iao iS) es pe 105» z so. [Biao . [simo. |b /ao. [Bima [Bjos © 5+ [g{ so. |Blaso (80: Z/na. 3/208 eles was [Bf sao + [Etec - [S| [alaro- |@laos- [elias + as [Spod | fas | yaeo Eizo: [3ins- [pes us | feos joxrs | foe* [olaro+ | pees: | dee + 155+ ws: | jaso- | [sas | yor | diez | |rea~ wes [gar jglsas|plae [psa lol ua lg) ar: s+ [801 - [loo |S]ma- [Slme- [8] w+ [ele as |Slors- [Slo |Sless~ |8|n0 [S| wor (8) uo ms+ Jgjos + Ioiasa. |ylzs- glia 3 1386 a) tts ass |B 0s - [3jma- 322+ |3)eo- |8) too Br ms+ [3)r7~ |e) os [8/99- [B|see- |B] w2- [ere | ms: |Bl20- |[B\mo- |Eler= Biise- |B) ae [Blo - mae [5 ass = Biter _[5|75+ [Sue [3] tor [5/90 Bs + 240 fies. | 165+ fag tore | fast ws» | | a7. vss | [55- | | aa | free | ass | | ata. wT 148. 122+ ag | 74+ ass | |» sss | [tae | ins. ag + | j7o+ 25 + 192. 147» 130 « 10.8 « 78 + 65° moss | yte2 + tao | p22 | prozs 4s | pot Figure 48, fete Crna Oneraor Hancock Rev Aor 98 PageNe 72 LIEBKERR OFFSHORE CRANE load diagram BOS 40/2400 D MAIN HOIST 3 = fall operation wave teigth SWL (tonnes) wave ne A save Sogn oe Figure 49 OS 100 OFFSHORE PEDESTAL CRANE LOAD RADIUS CHART HOIST REEVE = TWO FALL WEIGHT OF HOOK BLOCK = 1800 KG BOOM LENGTH = 46.5 METRES napus | ae [haa | area | aa 121 | Bb [etna te wid Ste wo | 240 | 200 | eno | 240 zoo | 240 | 240 | 200 | eno aso | 240 | 240 | 25s | r20 zoo | 200 | 235 | ws | sas seo | vr | ws | ws | ns soo | 5 | se | os | ae Figure 50 Ottenore Crane Opersor Hanson Rev Api 06 Pa 0 79 shore Cane Operator Handbook Rov 0% Ape 08 Poneto 74 RATED CAPACITY INDICATORS (RCI) (AUTOMATIC SAFE LOAD INDICATORS ASLI) Otihore Crane Operator Hansbook Rev01 ap o6 Page No 75 RATED CAPACITY INDICATORS Statutory Instrument 1998 No. 2307 - The Lifting Operations and Lifting Equipment Regulations. The Approved Code of Practice (ACOP). Section 4 states: ‘Where there is a significant risk of overturning andor overloading arising from the use of equipment it should be provided where appropriate with equipment or devices such as Rated Capacity Indicators and Rated Capacity Limiters. Such devices provide audible andlor visual ‘warning when the safe lifting limits are being approached. Section 7(b) ‘Where there is a significant hazard arising from the use of the machinery it should be provided with appropriate equipment or devices such as Rated Capacity indicators and Rated Capacity Limiters. A rated capacity indicator was originally referred to in the United Kingdom as an Automatic Safe Load Indicator (ASL!) but due to European alignmentilegislation, Rated Capacity Indicator (RC!) is the preferred option, ‘There are many approved types available, but, again, by law they must: 1. Visually Warn the operator when the crane is approaching the Maximum SWL for any boom length and radius 2, Audibly and Visually inform the operator and others in the vicinity when the crane has reached an Overload condition Visual signals are usually coloured lights AMBER for approach to SWL In some cases, a dial indicator can replace or supplement the AMBER light RED for Overioad The red light should be accompanied by an audible signal, generally a bell or horn There are systems that do more than is required by law. i It is the crane operators responsibility to know the type of indicator fitted to his machine. He must also know how to set-up the icator and to adjust where necessary for any particular duties that the crane is required to perform. . Itis also the operator's responsibility to prevent the crane from becoming overloaded. If the RCI /ASLI indicates an overload, the operator must take immediate action to return the crane to a safe condition i.e. by lowering the load and/or reducing the radius to a safe point + NOTE The operator must never lift a load if an overload signal is being registered. Dshore Crane Operas Handbone ev 01 Apel 08 PageNo 78 TYPES There are many makes of RCV/ASLI that are approved under the various regulations. ‘They fall into 3 main groups. 4: NOTE Otthore Cra MECHANICAL TYPE This type is usually fitted into the boom hoist system. They sense the tension (pull) in the boom hoist and are mechanically linked to the crane to allow for changes in boom angle (radius). (One of most commonly available of these types is manufactured by Wylie). HYDROSTATIC TYPE These indicate the weight of the load being lifted. They may be mechanically connected to the boom to compensate for changes in radius or be used in conjunction with a mechanical type system in the boom hoist. (Weighload was a manufacturer of this type). ELECTRONIC TYPE This type uses angle and sometimes pressure sensors and load cells in various parts of the system. These send signals to a computer which must be changed/configured by the crane operator to conform to any of a range of different lifting duties for the crane, Whatever the type, the crane operator will have to take certain steps to set up and test the RCI fitted to the crane. Operter Handbook Fev 01 Agri 06 Page No 77 WEIGHLOAD CRANE AUTOMATIC SAFE LOAD INDICATOR EQUIPMENT Cents te oan Bas pre é Figure 54 DESCRIPTION The basic equipment consists of the following components: + Dynamometer ‘+ Load Cell and Flexible Armoured Capillary. permanently connected to: + Controller Unit + Warning Box The weighload incorporates a mechanism for automatically comparing actual load with the safe working load. If the safe working load is approached, an amber light comes on in the crane cab. If the safe working load is exceeded then a red light shows and a warning bell sounds. Cftenove Crane Operator Handbook Rev 01 Ronis Page No 78 The principle of the weighload operation is as follows: * A dynamometer is situated on the hoist line between the hoist drum and the jib head, ‘on 5 sheaves, one of which is pressure sensitive, Figure 52 The dynamometer is rigidly mounted in the run of the hoist rope between the hoist barrel and the apex pulley on the boom. The pulley of the dynamometer is so arranged as to slightly deflect the hoist rope from its natural path causing a load to be felt by the dynamometer in direct proportion to the tension in the rope Le. in proportion to the weight on the hook. A stirrup carried by the pulley rests on the load cell, mounted on the fixed frame of the dynamometer, the load cell sensing the load on the sheave. A hydrostatic pressure is therefore generated within the load cell and transmitted by means of the armoured capillary tube to the controller unit situated in the crane cab in full view of the operator. CONTROLLER UNIT Variable duty control box, having a cam operated by a drive from the crane boom that modifies the SWL (Safe Working Load) according to the working radius. ‘The cam automatically provides a smooth loadradius curve and is produced from the manufacturers load charts. All control units contain a scale and two pointers one black, one red. The black pointer indicates the weight being lifted The red pointer indicates the maximum safe working load that can be lifted at varying radii/boom angles There is also a Fall Change Adjuster on the control unit. When this is rotated it will automatically alter the lifting capacities shown on the Scale. If the number of falls is altered @ cam showing the equivalent number of falls should be installed. (Offshore Crane Cperator Handbook ev 01 Ape 96 Pape No 79 WARNING BOX The warning box is mounted in the crane cab and consists of a horn or bell unit with optional amber and red warning lights. The Amber light is normally set to indicate that the maximum safe working load has been reached. ‘The Red light and the Audible warning denotes the safe working load has been exceeded by 10%. The crane operator should take corrective action when the first visible amber warning light comes on. Since approximately 10 - 12 % additional loading is required to trigger off the next danger signal, the red light and warning bell should rarely be activated and then only for a brief moment. Safe operating depends on the Rated Capacity indicator (Automatic Safe Load Indicators) being in working condition and no crane should be operated with defective indicators. In particular the sound warning system should not be rendered ineffective by the operator. This warning bell must be audible to persons outside the cab situated within 1 % times the boom length. All Rated Capacity Indicators (Automatic Safe Load Indicators) are sensitive instruments and are calibrated only for cranes on firm, level and uniform ground. Specialist skills are available for repairing defective indicators and operators are instructed to call the spacialist rather than attempt repairs/adjustments themselves, There are several versions of Rated Capacity Indicators (Automatic Safe Load Indicators) in use, some manufacturers are: WEIGHLOAD WYLIE ECKO AUTOMATIC CRANE STOPPER (A.C.S.) MIPEG PAT LOADWATCHER Crfshore rane Operator Haeook Revo Agric Page No a0 MIPEG R.C.l. tise Grane Operator Handbook Rev0t Apri 0s Page No 61 MIPEG SAFE LOAD INDICATOR ‘System Overview A Mipeg Safe Load Indicator will normally comprise the following parts: + Operators display unit, installed in front of the crane operator » Boom angle sensor, installed at the boom foot of the crane * Main load hoist sensor, connected to the main hoist rope * Whip hoist sensor, connected to the whip hoist rope All the above components will be hardwired into the machinery house or in the operatorrs cabin, eg Computer cabinet mounted in the Additional sensors may be connected to the system to monitor other crane and operational parameters such as: * Crane overturning moment using a boom hoist moment sensor + Rope speed and direction, using encoders reading rotating sheaves or winch drums (R.S.|. Rope Speed Indicator * Crane slew position, using encoders installed in the crane slew system * Gross Overload Protection. All these sensors are read by the Mipeg computer. The in-built software is programmed to fulfil the authoritiesr requirements and to enhance and assist in crane operation safety. Mipeg Computer Cabinet All Mipeg components are hardwired into the Computer Cabinet. The computer will read all the sensors on a continuous basis and monitor the quality and correctness of the data; it has special project software which covers the unique design criteria for the specific application. Based on the sensor data and the software, the computer will set outputs. These outputs could be warning limits as buzzers and lights trigger the external crane hom and activate crane inhibits such as boom down inhibits and/or angle limits The software may be changed if crane specification or operational criteria are changed. The computer sends information to the crane operator through the Operator's Display. COrthore Crane Operator Manbook Rev 0% Api 08 agen 82 Mipeg Boom Angle Sensor The boom angle sensor is installed at the boom foot section. The sensor is measuring the ‘boom inclination above the horizontal. The sensor is a gravity based sensor which means that one part will always point vertically downwards and the other part will follow the crane boom movement. The crane geometry is part of the Mipeg software and the measured boom angle will be an input to a calculation with the end result being hook radius measured from the centre of rotation. Figure 63 Mipeg Boom Angle Sensor Mipeg Load Hoist Sensor A load hoist sensor measures the load seen by the crane hook. ‘Some cranes have two separate hoist winches: 1 a main hoist rigged to lift heavier load in multiple parts of line 2. a faster, single part of line winch; the whip line In principle there are only two ways of measuring the hook load Dead end links ‘One type of sensor is the dead end link sensor which may be used if the crane is rigged in a permanent even number of fails (2, 4, 6...) The sensor is designed to be a link betwoon the rope wedge socket and the end eye on the crane. The sensor is designed to suit the maximum rope load. This type of sensor is always proof load tested by the authorities to 2 x maximum rope load. The sensor output, which is in proportion to the hook load, is read and converted to the actual hook load by the Mipeg Computer Cabinet. Fig 54 Mipeg Dead End Link Ottshore Crane Operator Handbock Revo Api 08 Page No 83 Rope Deflection Sensors The other type of sensor is a rope deflection sensor. This means that as the rope is deflected a proportion of the load on the hook is seen by the sensor. This deflector type sensor could be designed as a pin type sensor, replacing a sheave pin or an engineered sheave assembly to be added onto the existing crane. There are many designs which will deflect the rope and function as load hoist sensor. These sensors are normally used as whip line sensors or main line sensors when odd ‘numbers of falls are a requirement. The output from the sensor is again calculated to display the "Hook Load! to the operator. Figure 55 Rope Deflection Sensor (shore Grane Operator Handbook Revo Aosi0s Pops to 88 MIPEG 1000 SYSTEM CONFIGURATION SENSORS ON CRANE STRUCTURE Lowahott Beem helst sents) &puey Compur cabin eegiB Te Drivers pty 724000 supply Power WOMoAC OFFICE/CONTROL ROOM ‘Computing, storage & veut play Figure 56 Otshore Crane Operator Handbook Rev 0% Agni 06 Page io 85 Hook Loot Wandin ‘Load in tlook (Lbs) — Aber weening Light Maabing when loud>95% SWE Gor Melo Readius Window PLePlatform Curve. = wats revaing uk Radius (Peet ‘SU=Sea Cure oa fig fo in allenative motel Fall = Heat alarm Light Flashing when loxd> 110% SWL SMT Wide Safe Working Lond (Lbs) based upon Curve a Reds (ates fect oe lta select wa get lV FALLS ‘nin changes betwee Man Ld, «ln Wi kt eal ‘CURVE, change loud cv bine Pn (PL) wl Best) dt YAULS, yao together wil AUX iutante cing nen Mle ai nd Whip Mlatrestig| Fig 58 Mipeg 2000 shore Crane Operator Handbook Rev Apes Pepe No 66 Mipeg Operator's Display ‘The Mipeg Operator's Display is unique in design and based upon feedback from the end user, the crane operator. The most important information - % of SWL - is displayed using a large analogue needle operating on top of a green, yellow and red scale. The position of the needle is seen from the corer of the eye leaving the main view of the load uninterrupted. Additionally the following information is also displayed: HOOK LOAD - the actual load seen by the main block or the whip line RADIUS - the hook operating radius measured from the centre of slew rotation SEA CONDITION _ - the operator selected sea condition SWL - the Safe Working Load; based upon the radius and sea condition. The Mipeg Display has means of changing the operational parameters. These are altered/selected by the operator using push buttons, normally labelled ACK ~to acknowledge warming and alarm limits exceeded TEST - to perform a display "self-test" for verifying an operational display AUX or TIME ~ green button to select alternative digital information CURVE or WAVE - to select the sea condition and will re-rate the load capacity; SWL FALLS - to select parts of line and/or main/whip winch (in combination with the "AUX or TIME" button) There are three versions of these types of displays currently in use: Mipeg 500 Display Mipeg 1000 Display (Figure 55) Mipeg 2000 Display (Figure 56) Mipeg Recording Option The Mipeg product line currently has two system types, Mipeg 1000 and Mipeg 2000, which monitor and make an automatic crane usage record of every load cycle performed. This, among other important tools may be used fo enter into a Planned Maintenance Programme based upon actual crane usage. The data can be further analysed by the end user andlor the authorities. Ofishore Crane Operator Handbook Rev01 Apo Page No 87 A typical example of a crane usage record shown below: Page 1 OWNERS NAME / CODE CRANE ID PROGRAM ABC Oil Company 12 VERSA ACCUMULATED CRANE USAGE DATA FROM. DATE urs LOADS>85% | MOMENTS>70 USAGE HOURS 31 0CT-96 00014957 0000897 ——_oco00ts7 00000748 Page 2 cor DATA TIME PERIOD urts LOADS>85% — MOMENTS>70% USAGE HOURS 27 MAY.960¢ DEC-96 00002585 ooo00127 ——cagogoasa 0000048, POWER WARNINGS. MAIN RESETS ‘00000015 00000027 CRANE OPERATION REPORT PRINTED: 25 NOV 1996 1345 HOURS PAGE: 0002 (This Line added for clarity & reference) G23 0 4 6 6 7 6 9 44 42 13) ENO PEAK HOOK PEAK MAX RAD.AT RAD.AT DURA WAVE FALLS! SIP REC. OF HOOK LOAD MOME STAT PEAK MAX TION HEIGHT BOOM (+) NO. ut LOAD MOME MOME MONE LENGTH PIS cit) TMT) TAD TMH) sy) mG) see" NEW DATE : 24 NOV 1996 001 1924 13.0 103 152 144242400103. 0.0m —_1/82.000002 18:25 OVERLOAD EXCEEDS 110.% S.W.L. ALARM NOT ACKNOWLEDGED 003 1325 22.0 185 152 1442424 00:07 O.0M 1192.00 004 18:26 OVERLOAD EXCEEDS 110.% S.W.L. ALARM NOT ACKNOWLEDGED. 005 1326 228 193 152 144 «24 = 24 00:03 «0.0m 1192.00 0008 1326 60 4.0 144128 18170003. 1.0m — 1192.00 0007 1327 98 75 144 196 1717 00:03 3.0m 1132.00 ‘008 1523 OVERLOAD EXCEEDS 90.0% SW.L. ACKNOWLEDGED ‘0009 1623 148 140 152 1962217017 3.0M_—_1732.000010 “"* NEW DATE : 25 NOV 1996 011 1036 190 11.3 400 368 29290103 3.0M 2782.00 0012 REPORT ENDS AT: 25 NOV 1996 REPORT COMPLETED, Chore Crane Operator Hansbeok er 1 Ape 08 Pago No 68
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