Bulk Carriers: Guidelines On Early Assessment Of Hull Damage And Need For Abandonment

Unusual motion or attitude :

           → If a ship takes on an unusual trim or heel, or if her motions become changed, breach of the hull envelope should be suspected immediately.

           → Sudden changes of heel or trim will indicate flooding or in smaller ships with lighter cargoes it may indicate cargo shift.

           → Unusual collections of water on decks may be indicating trim or heel abnormality.

           → On smaller ships, slowing of the ship’s roll period may indicate excessive water within the hull - a serious threat to stability. Ship s fitted with GM meters should be able to identify any unexpected changes in GM.

           → Jerky lateral motions can be indicative of large scale sloshing as would be the case if a hold were flooded.

           → Increases of water boarding forward decks may indicate flooding of a forward compartment. Trim and freeboard changes are notoriously difficult to assess from an after bridge.

Methods of detection :

           → Hatch covers may be dislodged by pressure and/or sloshing from within a hold if flooding occurs through side shell or bulkhead.

           → Sudden pressurization of compartments adjoining those that are damaged or flooded will indicate failure of internal subdivision, most notably bulkheads.

           → Hull Stress Monitors, where fitted, may be able to detect unexpected longitudinal hull girder bending. Torsional stresses may also be detected through differential changes between port and starboard strain gauges.

           → Spaces may be monitored, either using gauging or bilge/water level alarms. Forward store spaces can also be monitored audibly using ‘talkback’ telephones that may be fitted in forward spaces. Anchor impacts and water in the space can be detected using telephones of the type that remain active until switched off from the bridge.

           → Visual monitoring from the bridge using binoculars, where fitted, by closed circuit television, can give indication of abnormal water on deck and local damage. However, assessment of trim or freeboard using this method is difficult.

           → Assessment of trim changes can in certain conditions be detected by noting the level of the horizon, when visible, against a known reference point on the foremast.

            → Draft and trim can be assessed using draft gauges. Changes are much more discernible using this method than by visual means from above decks.