Critical areas of structural concerns on
bulk carriers / dry cargo ships
1. Global longitudinal strength
2. Local strength
3. Flooding Risk
4. Risk to cargo concerns
1.Global longitudinal strength
¾ Primary members / areas:
1) Strength deck plating ( main deck plating outline of hatch opening).
2) Sheer strake
3) Bilge turn area ( to be inspected in dry dock or via underwater
camera)
¾ Ultrasonic thickness measurement:
1) 3 belts with one near midship area, which indicates the thickness
condition of all longitudinal members usually as elements for
calculation of the bending module.
¾ Loading / unloading sequence:
1) Improper loading or unloading will cause significant local stress which
has resulted in several capesized bulkers being damaged whilst in
port; the loading / unloading sequence should be checked.
2. Local strength
¾ Hotspots / fatigue points
1) Wind / water strake shell plating at fwd water ballast tanks always
impacting by sea water during heading.
2) Hatch corner deck plating and hatch coaming where potential cracks /
buckling caused during hull girder twisting / hogging / sagging
3) Corners of water ballast tanks surrounding the ballast hold(s), where
local stress usually is higher during deep ballasting
4) Any other discontinuous points in the longitudinal direction, such as
the connecting welds of hopper / sloping plating to fwd-end transverse
bulkhead (the collision bulkhead) and to aft-end transverse bulkhead (
ER fwd bulkhead), and ends of longitudinal hatch coaming stays
¾ Surrounding boundaries
of water ballast tanks adjacent to heated spaces
such as a heated fuel tank or machinery spaces
with higher temperature;
¾ Mechanical damages – shell damage by tugs; hold damage
by crabs; contact damage of shell at fwd area etc.
3. Flooding Risk
¾ Critical areas with invading sea water:
1) Forecastle spaces & FPT
2) Hold No.1 & 2
3) Any other compartments with opening(s) before collision bulkhead. (
special attention on ductkeel pipe tunnel, easily missed out by Class)
¾ IACS URS 26 – small access hatches to forecastle spaces on
forecastle deck (or fwd main deck);
¾ IACS URS 27 – air vent pipes on forecastle or fwd main deck
¾ IACS URS 30 – hatch cover stoppers at fwd hatches within
0.25L of the fore perpendicular, usually hatch No.1 & 2
¾ IACS URS31 – condition of shell plating with frames in all holds
which should be capable to stand for the stress from loaded cargoes &
sea
¾ IACS URS 19,21&22 – condition of double bottom tank in
hold no.1, tank top plating in hold no.1 and separation bulkhead between
hold no.1 & 2 for bulk carriers loading with cargoes of density more than
1.78t/m3.
4. Risk to cargo concerns
¾ Hatch covers
¾ Pipes passing in holds
1) Air vent pipes from double bottom water ballast tank – by hydro
testing
2) Air vent pipes from double bottom fuel tank – by visual close up
inspection
3) Sounding pipes
4) Other pipes leading to the hold – CO2 pipes, conduit pipes, etc.
¾ Surrounding boundaries
1) Tanktop plating (inner bottom plating) with manhole covers
2) Hopper plating
3) Sloping bottom plating
4) Hatch coaming plating
5) Collision bulkhead
¾ Bilge wells
