TIMBER DECK CARGO

Hazards Associated with carriage of Timber

— water absorption
— ice accretion
— free surfaces in slack tanks
— trapped water within stow (especially logs)
— Cargo shift due to improper lashings
— Reduced GM
Carriage of timber on deck

Carriage of timber on deck offers an added advantage to the timber carrier ships.
Timber carriers are constructed with special requirements in accordance with
"Code of safe practices for ships carrying timber deck cargoes". These ships when
loaded with timber on deck and when the timber on deck is secured in the
required manner in accordance with the approved lashing plan for the vessel, are
permitted to load cargo to increased drafts called the timber load lines. The Load
line convention also mentions the requirements for use of timber load lines
The variable factors with reference to above are the stability of ship and stowage
and securing of the timber cargo in the required manner. Fulfilling these criteria,
ships can enjoy deeper drafts. The stowage and lashing requirements for timber
deck cargoes are as follows.

Prior loading timber cargo on weather deck, hatch covers and other openings to
spaces below that area should be securely closed and battened down. The air pipes
and ventilators shall be suitably protected from deck cargo. The deck shall be free
from any accumulations of ice and snow. All deck lashing gear and upright shall be
in sound condition ready for use. The access to crew quarters, pilot boarding access,
machinery spaces, safety equipments, remote valves, sounding pipes and all other
areas regularly used in the necessary working of the ship shall be kept free. Guard
rails or life lines spaced not more than 330 mm apart vertically shall be provided on
each side of the deck cargo to a height of at least 1 metre above the cargo.
The height of the timber deck cargo above the weather deck on a ship within a
seasonal winter zone in winter should not exceed one third of the extreme breadth
of the ship. The height of timber on deck shall not obstruct the navigation bridge
visibility as per IMO visibility criteria. The cargo shall not project overhanging
shoulders to head seas. And the deck load density of deck and hatch covers shall
not be exceeded in any case.
 Regulations & Publications
Merchant Shipping (Deck Cargo) Regulations 1968 - UK Statutory instrument with
respect to requirement to carriage of deck cargo in general and additional
requirements for timber deck cargo.
IMO code of Safe Practice for Ships Carrying Timber Deck Cargoes (1991)
SAFETY MEASURES FOR VESSELS ENGAGED IN THE CARRIAGE OF TIMBER
Masters of vessels engaged in the carriage of timber are advised to take the
following measures. They should:

a. ensure that the bilge wells are cleaned every voyage and the bilge pumping
arrangements are tested before the commencement of loading;

b. supervise the loading operations to prevent any damage to ship's hull, frame or
hatch covers caused by careless loading;

c. examine the hull plates externally at regular intervals to check for any traces of
cracks particularly in the number 1 and 2 holds and if any cracks are noticed they
should be repaired before leaving the port;

d. ensure that all the deck openings are securely closed and battened down;
e. ensure that ventilators and air pipes are effectively
protected from damage by the cargo;

f. sound the holds frequently especially in head sea conditions;

g. ensure that the vessel has adequate GM during the voyage;

h. check the vessel's list frequently during the voyage; and

i. deviate to a port of refuge if it is discovered that the

vessel has taken in water in her hold(s).
 MERCHANT SHIPPING (DECK CARGO) REGULATIONS 1968

PART 1 - Requirements which apply to ALL deck cargoes

• Avoid excessive loading
• Adequate stability at all stages of the voyage especially with regards to :-
• Vertical distribution of the deck cargo.
• Wind moments produced by strong winds.
• Loss of bottom weight- consumption of stores, fuel, fresh water.
• Increase in weight - water absorption by deck cargo, icing etc.
• Ensure the proper protection of watertightness ventilators, air pipes and the
of lower compartments.
• The height of the stow not to interfere with the navigation
• Access to the ship's steering gear not be obstructed.
• Crew should be provided with a safe means of access : Underdeck & on deck
passage, walkway

380 mm

380 mm

250 mm
The guard rails or wires should be a height of not less than lm and each set should
consists of three courses. No opening below the lowest course should exceed
230mm in height and opening above that course should not exceed 380mm in
height

All deck cargo should he adequately secured. When timber deck cargo is stowed in
any well it must be stowed as solidly as possible to extend over the entire available
length of the well to a height not less than the standard height of a superstructure
other than a raised quarter deck.

A walkway must be provided on top of the timber even if the ship has a permanent
passageway. Stowage : Compact, efficient lashings with accessible releases.
Uprights if required - should be of adequate strength, secured in position by angles
or metal sockets, and the spacing between any two uprights must not exceed 3m.
Use of Lumber (Timber) Loadline
The general principle is that if a vessel is of adequate strength to permit deeper
immersion while carrying a deck load of timber properly secured, its effects are
threefold :
• Increased reserve buoyancy by the compact mass of buoyant timber above the
freeboard deck
• Increased effective freeboard with beneficial effect on the range of stability
• The weather deck hatches are protected
PART II - Additional requirements applicable to Timber Deck Cargo
Section A - applies to :
• ships not marked with timber loadlines
• ships that have timber loadline marks but which are loaded within the limits of
ordinary loadlines.
In addition to Part I, :
• in a winter period, HEIGHT of cargo above weather deck not exceeding 1/3 of
the extreme breadth of the ship
• When stowed in any well, it must be solidly extended over the entire length of
the well to a height not less than the standard height of a superstructure other
than a raised quarter deck
• A walkway must be provided on top of the timber even if the ship has a
permanent passageway.
• Stowage : compact, efficient lashings with accessible releases.
• Uprights if required - should be of adequate strength,
• secured in position by angle s or metal sockets, and the
• spacing between any two uprights must not exceed 3 m.
Part II : Section B -Additional requirements for Timber Deck Cargoes in vessels
loaded to Timber Loadline

• efficiently secured throughout its length by independent overall lashings

spaced not more than 3 metres apart.
• lashings secured to eye-plates- interval of not more than 3 metres.
• 1st eye-plate and lashing not more than 2 m from end bulkhead. If no
bulkhead, 0.6 and 1.5 m from ends of the timber deck cargo.
• Lashings of close link chain (<19mm) with sliphooks and turnbuckles accessible
at all times.
• If length of timber less than 3.6m- lashing spacing to be reduced.
 IMO Code of Safe Practice for Ships Carrying Timber Deck Cargo
Should be compiled in conjunction with M.S.Deck Cargo Regs.
Additional requirements laid down by this code :
Lashing intervals in relation with cargo height
Cargo height 4 m & below : 3.0 m
Cargo height above 4m : 1.5 m
Linear interpolation for intermediate height
Lifeline of wire rope with stretching device near vessel’s C/L in addition to
walkway
Stability information pertaining to deck cargo- available to master
Master must verify vessel’s stability for worst service condition –
increase deck weight due to :
water absorption
ice accretion
variable in consumables- fuel, FW
 Packaged Timber
The cargo is stacked rather than stowed which leads to cargo movement, slack
lashings and subsequent damage.
Random lengths are not to be stowed on deck unless :
They can be stowed compactly
They are not stowed on exposed surfaces
Bonding should be strong to avoid disintegration.
Deck surfaces to be made level with timber before loading.
Dunnage between layers to bind the stow and keep it level.
Stow and secure other timber cargoes independently
Generally athwartship stowage avoided, particularly in adjacent and two top
layers.
Rounded angle irons, at least one foot long should spread the load of the lashings
at the upper corners of the stow.
 Height of Cargo

at seasonal winter zone in winter, the height of the cargo above the weather deck
should not exceed 1/3 of the extreme breadth of the ship

Height of deck cargo should take into account its weight does not exceed the
designed max. permissible load on weather decks and hatches

Height restricted so that :

visibility from Nav. Bridge is not impaired
any forward facing profile of deck stow does not present over-hanging shoulders to
a head sea.
 General guidelines for loading Timber Deck Cargoes
• All securing equipment should be laid out -visual examinations at intervals not
exceeding 12 months.( prudent inspect before use)
• All equipment, such as shackles, marked and certification in order.
• weld additional securing points, such as eye-plates, if required.
• Outboard ends of lashings secured to eye-plates before loading
• Test vessel stiffness by resulting movement of ship using cargo lift.
• Protect ventilators, air pipes, sounding pipes, winches and-similar dock
appliances.
• When necessary, lay dunnage (3 x 12m) at l m apart.
• All hatch covers, watertight doors, and means of securing air pipes and
ventilators within area to secure before loading commence.
• Neatly stow the timber, interlocks within each layer. Do not "stack"timber piece
on piece as this will not ensure compact stow.
• after the initial securing of the cargo, " tightening devices should be capable of
further tightening for use on the voyage.
• lashings and other securing arrangements frequently inspected on passage
• A record of inspections and tightening of lashings should be kept.
• On a long voyage it may he necessary to re-coat wire lashings with a suitable
anti-corrosion compound.
• Chock each tier, fill gaps with loose timber
• Fence off openings to prevent accidents
• Ladders or steps provided from deck to top of cargo
• Generally stow cargo F & A to facilitate lashing
• Distribute weight evenly and avoid excessive height
• Examine slip hooks - ensure cannot work looseNo cargo protruding at outboard
edges of stow- interfere lashing
• Check stability before completion of loading
Actions to be taken during the voyage
Voyage planning
1) During voyage planning, all foreseeable risks which could lead to either excessive
accelerations causing cargo to shift or sloshing sea causing water absorption and
ice aggregation, should be taken under consideration.
2) Before the ship proceeds to sea, the following should be verified:
.1 The ship is upright;
.2 The ship has an adequate metacentric height;
.3 The ship meets the required stability criteria; and
.4 The cargo is properly secured.
3) Soundings of tanks should be regularly carried out throughout the voyage.
4) The rolling period of the ship should be regularly checked in order to
establish that the metacentric height is still within the acceptable range.
5)In cases where severe weather and sea conditions are unavoidable, the Master
should be conscious of the need to reduce speed and/or alter course at an early
stage in order to minimize the forces imposed on the cargo, structure and lashings.
6) If deviation from the intended voyage plan is considered during the voyage,
a new plan should be made
7) As a final resort when all other options have been exhausted if the list is to
be corrected by jettisoning deck cargo, the following aspects should be
noted:
a) jettisoning is unlikely to improve the situation entirely as the whole stack
would probably not fall at once;
b) severe damage may be sustained by the propeller if it is still turning when the
timber is jettisoned;
c) it will be inherently dangerous to anyone involved in the actual jettison
procedure; and
d) the position of the jettisoning procedure and estimated navigational hazard
must be immediately reported to coastal authorities.
8) If the whole or partial timber deck load is either jettisoned or accidentally
lost overboard, the information on a direct danger to navigation should be
communicated by the master by all means at his disposal to the following
parties:
.1 ships in the vicinity; and
.2 competent authorities at the first point on the coast with which he can
communicate directly.
Such information is to include the following:
.3 the kind of danger;
.4 the position of the danger when last observed; and
.5 the time and date (coordinated universal time) when the danger was last
observed
Cargo safety inspections during sea voyages
Cargo safety inspections
In accordance with the items below, should be frequently conducted throughout
the voyage.
1. Prior to any inspections being commenced on deck, the Master should take
appropriate actions to reduce the motions of the ship during such operations.
2. Close attention should be given to any movement of the cargo which could
compromise the safety of the ship.
3. When safety permits fixed and portable lashing equipment should be visually
examined for any abnormal wear and tear or other damages.
4. Since vibrations and working of the ship will cause the cargo to settle and
compact, lashing equipment should be retightened to produce the necessary
pre-tension, as needed.
5. Uprights should be checked for any damage or deformation. 13)Supports for
upright should be undamaged.
6. Corner protections should still be in place.
7. AII examinations and adjustments to cargo securing equipment during the
voyage should be entered in the ship’s logbook
Rolling period test
The metacentric height (GM) can be determined approximately by means of
a rolling period test. It is performed by measuring the rolling period of the
vessel.

Stiff vessels have a high metacentric height (GM) and a short rolling period;
while vessels with a low metacentric height (GM) have a long rolling period.

The rolling period test is a frequently used method to determine the

stability of smaller vessels. Rolling period test can be performed at any time
and the crew can perform it themselves.
The test can be performed in the following way:

Mooring lines should be slack and the vessel should not be too near the
harbour.
The vessel is made to roll.
When the vessel’s roll is sufficient (approximately 2 - 6° to each side) the vessel
is allowed to roll freely and naturally.
The time is taken which it takes the vessel to go approximately four complete
oscillations. (One complete oscillation will have been made when the vessel has
moved right across to the other extreme side (i.e. starboard) and returned to
the original starting point).
The time in seconds (T) for one oscillation is found by dividing the number of
oscillations made with the total time.
If the calculated value of T, in seconds, is less than the breath of the vessel (B), in
metres, it is likely that the initial stability is sufficient, provided that the vessel
carries full supplies and has high freeboard.

As the vessel’s supplies decreases the rolling period (T) becomes longer since the
vessel’s centre of gravity (G) becomes higher and the metacentric height (GM)
becomes larger. In such circumstances it is recommended that the calculated
value of T, in seconds, should not be more than 1.2 times the breath of the
vessel (B).

This method is not applicable to vessels with a hull shape that dampens the
rolling, for example vessels with large bilge keels or vessels of an unconventional
design, such as high-speed vessels.