Freeboards

Ahoy There!I often use the expression “watch your freeboards” when thinking something bad is about to happen, or advising against something. I knew it meant how many boards must remain visible (above water) for a vessel to be seaworthy. I came across some chartering terms while reaffirming my idea of SHINC and bam cut & paste away.

FREEBOARDS:The basic freeboards that are calculated according to these rules depend on the length and type of vessel. “Type A vessel” is designed to carry only liquid cargoes in bulk and in which the cargo tanks have only small access openings closed by watertight gasketed covers of steel or equivalent material. These vessels are assigned with the lowest freeboards owing to the fact that because they ‘are nearly sealed, their buoyancy is unlikely to be lost unless they are damaged.

All other ships are “Type B vessels”. Basic Type B freeboards are larger, which means a lower draught. The Type B freeboard can be increased or reduced depending on the type of ship and its fittings. If vessels have old-fashioned hatchways covered with portable beams and covers, their freeboards are increased. Vessels having steel weathertight covers fitted with gaskets and clamping devices, improved crew protection, better arrangements for freeing water on deck and good subdivision characteristics, are considered to be safer and can have a freeboard reduced from the basic Type B freeboard. A greater reduction can be enjoyed by such vessels up to the total difference between the Type A and basic Type B freeboards. The Type B vessel which is assigned a Type A freeboard is called a “Type B - 100” vessel. Its subdivision requirements will be very severe. Other Type B vessels may be assigned a freeboard based on 60 per cent of the difference between Types A and B freeboards if their subdivision requirements are less severe.

Bulk carriers will be most advantaged if they can reduce their freeboards and load to deeper draughts. Ore carriers with two longitudinal bulkheads may be as sealed as tankers and can enjoy the B - 100 freeboard.
Good Fortunes