Vessel Stability
Modifications to vessels can cause changes in stability that can have major implications for the safety of the vessel. Have vessel checked whenever major changes are made.
Factors that can impact on stability include:
- A vessel that is overloaded or has major water accumulation on deck (or in the holds / engine room).
- The incorrect loading of cargo, fuel in drums, etc. on deck.
- Cargo shifting, can have fatal consequences – make sure deck cargo is securely tied down and correctly loaded for maximum stability.
Any changes to a vessel’s load-carrying capacity are critical to your
vessel’s stability safety and the reserves of buoyancy it will have at larger angles of roll.
Crew need to understand that generally the centre of gravity tends to move towards any added weights and away from any weights that are removed. If you add weight higher up on the vessel, the centre of gravity will rise and promote a top-heavy or ‘soft’ feeling. For example, if you add extra weight on deck or lift an object with a high derrick (crane), the centre of gravity moves up. And, if you reduce weight from low in the vessel (such as using fuel from low down in the fuel tanks), the vessel will become more top heavy, again affecting stability.
A heavy roll or a breaking wave that results in down-flooding will make the vessel less stable and multiply the problems the vessel experiences next.
Take these measures to avoid this hazard:
- Have your vessel’s stability checked after any significant changes to gear, layout, etc.
- Ensure your bilge alarms and bilge pump are working.
- Test them every trip.
- Make sure scuppers / freeing ports are working correctly, and not blocked by gear, fish, etc.
- Never silence a bilge alarm without fixing the problem – it’s sounding for a reason!
- During normal operations, keep closed any doors and hatches that do not need to be open.
- Keep all doors and hatches free of lines, wires and obstructions.
- Ensure all hatches are fully secured and dogged down when they need to be.
