Illustrate both the side and bottom plating as a continuous whole and shows the numbering of plates and lettering of plate strakes for reference purposes.
These plans are essential for describing the locations of damage to the shipâ€™s shell and connections to the shell. This plan shows the boundaries of the shell plates and thickness of each plate in millimeters.Recent bulk carriers built to IACS common structural rules show net scantlings, on which strength calculations are based, as well as gross scantlings which include corrosion addition plus ownerâ€™s addition, when applicable. In other words a minimum and maximum is shown for each plate thickness.The frames, floors, girders, longitudnals, bilge keels and stringers which make contact with shell plates are also shown.The locations of other features such as sea chests and anchor pods are also shown.Frame numbering appears at the bottom and top of the plan, counting forward and aft, from zero at after perpendicular(at the rudder stock) The limits of each cargo hold are also shown at the top of the plan.Generally a convention is adopted for naming or numbering the strakes of the platings, with A, B, C etc starboard or port from the midships(where the greatest number of strakes are found) and A being the keel plate
Following incidents resulting from structural failure in oil tankers, the IMO developed requirements aimed at inhibiting
corrosion in cargo oil tanks by way of performance standards. These performance standards are now being made
mandatory by an amendment to SOLAS: regulation II-1/3-11, Corrosion Protection of Cargo Oil Tanks of Crude Oil Tankers,
adopted by Resolution MSC.291(87).
The legislation applies to new crude oil tankers of 5,000 dwt or above engaged on international voyages as follows:
â€¢ Contract date: 1 January, 2013
â€¢ Keel laying date: 1 July, 2013
â€¢ Delivery date: 1 January, 2016
The regulations provide three options to address the corrosion protection in these areas
Option 1 â€“ Coating
The first option requires the coating of cargo oil tanks during the construction of the ship in accordance with the
â€˜Performance Standard for Protective Coatings for Cargo Oil Tanks of Crude Oil Tankersâ€™
Option 2 â€“ Alternative means: Corrosion-resistant steel
The second option allows cargo oil tanks to be protected by what the regulation refers to as â€œalternative meansâ€. One such
example is the use of â€œcorrosion-resistantâ€ steels which have the goal of maintaining the required structural integrity for 25 years
Option 3 â€“ Exemption
The regulations allow a third option, in which a vesselâ€™s flag state may choose to exempt a crude oil tanker from the
requirements described in option 1 and option 2, if the vessel is built solely to carry cargoes or perform cargo handling
operations with cargoes which do not cause corrosion
Where the cargo oil tanks are coated or protected by the use of corrosion-resistant steels in accordance with the IMO
regulations, Lloydâ€™s Registerâ€™s verification shall be indicated by the class notation ShipRight ACS(C), where ACS denotes
anti-corrosion system and C denotes cargo oil tanks.
Areas to be protected.
1) Deckhead with complete internal structure, including brackets connecting to longitudinal and transverse
bulkheads. In tanks with ring frame girder construction the underdeck transverse framing to be protected
down to level of the first tripping bracket below the upper faceplate.
2) Longitudinal and transverse bulkheads to be protected to the uppermost means of access level. The uppermost
means of access and its supporting brackets to be fully protected.
3) On cargo tank bulkheads without an uppermost means of access the protection to extend to 10% of the
tankâ€™s height at centreline but need not extend more than 3 m down from the deck.
4) Flat inner bottom and all structure to height of 0.3 m above inner bottom to be protected.