Watertight Integrity and Freeing Port Decisions Before Heavy Weather
A 12,000 dwt general cargo ship is completing loading. The forecastle is a raised type with a breakwater, but the forward well deck has two freeing ports on each side, one of which on the starboard side is stiff and partly blocked with cargo debris. The weather deck hatches are steel with tarpaulin and cleats. The load line is being approached but not exceeded. The barometer is falling rapidly and the master expects heavy weather within 12 hours. The chief officer wants to sail because the berth is needed and the forecast may improve.
1. Evaluate the watertight and weathertight integrity of the ship for the intended passage and state what must be corrected before departure.
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The critical item is the freeing port. Freeing ports are part of the ship's statutory drainage arrangement for wells and decks; their effective area is set against the volume of water that can be shipped. A partly blocked port on one side reduces the drainage capacity asymmetrically, which can lead to water accumulating on the starboard side of the well deck and to a persistent list, and it also increases the risk of green seas loading the hatch covers. 'Stiff and partly blocked' is a defect, not a preference, and it must be cleared and the hinge freed and greased before departure.
Next, the hatch covers. Steel covers with tarpaulin and cleats are weathertight only if the packing is sound, the cleats are all set, and the tarpaulin is intact and properly secured. The chief officer should confirm the packing condition, cleat tension and tarpaulin integrity, and the drain channels and non-return valves should be clear.
The load line being approached but not exceeded is acceptable in itself, provided the freeboard and the minimum bow height are maintained and the forward well is not over-loaded by deck cargo that would trap water. Judgement: the ship should not sail with the blocked freeing port; that is a clear defect to rectify. The other items are checks that must be completed and recorded before departure. The reasoning to show is that watertight/weathertight integrity is a set of specific, verifiable items - freeing ports, hatch packing and cleats, tarpaulins, drains - each with a defined standard, not a general impression.
2. The master decides to sail after the port is cleared. Set out the operational precautions you would recommend for the passage and justify each.
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Reduce speed and alter course to avoid excessive pitching and slamming, because the forward well deck is the most exposed area and slamming loads act directly on the hatch covers and the breakwater. Keep the ship at a heading that limits green water over the bow rather than taking seas on the beam, which would load the freeing ports on one side and aggravate any list.
Maintain a regular inspection round of the well deck, freeing ports and hatch covers during heavy weather, because a port can become blocked again by debris or a cleat can slacken, and early detection is the only defence. Log each round.
Keep the ballast system ready and use ballast to control trim and list, because a slight stern trim raises the bow and reduces slamming, and because counter-ballast is the practical response if water accumulates on one side. Do not, however, use ballast to compensate for a known drainage defect.
Secure all deck cargo and lashings and confirm the hatch tarpaulins are not chafing, because chafe opens a path for water ingress. Brief the crew on the specific risks and the reporting routine.
The justification throughout is that the ship's protection against heavy weather is a combination of avoiding the load, preserving drainage, and detecting deterioration early - each precaution maps to one of those.