SOLAS Watertight Integrity Inspection: Doors & Hatches

Watertight integrity is the one system on board that does nothing at all until the day it is the only thing keeping the ship afloat. A door that will not seat, a hatch packing with a permanent groove in it, a drain channel packed with cargo residue — none of it shows up in a performance report, none of it triggers an alarm, and all of it sits quietly between a manageable ingress and a progressive flooding casualty. It is also, from an inspection point of view, unusually unforgiving: a Port State Control officer can find most of these defects standing on deck with a torch and a chalk stick, in the first twenty minutes of an inspection, before anyone has opened a single certificate.

This guide covers what a chief officer is actually responsible for proving: the boundaries that make up the watertight envelope, the timings and indicators SOLAS sets for watertight doors, how hatch covers are tested and when packing and steel have to be renewed, what the drain and non-return arrangements are really for, and the records that turn all of it into evidence.

SOLAS watertight integrity: the three boundaries you maintain

People use “watertight integrity” as though it were one thing. On a working ship it is three separate systems with three separate failure modes, three separate maintenance regimes and, usually, three separate people who think somebody else is looking after them. Getting the inspection right starts with keeping them apart in your own head.

The distinction matters for a practical reason. A weathertight defect is usually a maintenance finding with a deadline attached. A watertight subdivision defect is a class matter and may need a surveyor. A closing appliance that does not work, or is found open when it should be shut, goes straight to the detainable end of the scale — and it is the one you can fix before the inspector arrives. If you keep the three categories separate in your inspection routine and in your records, you stop the cheap findings hiding behind the expensive ones.

Watertight door inspection: the timings SOLAS sets

Watertight doors are the part of the system with actual numbers attached, which makes them the part an inspector will test. A power-operated sliding watertight door has to close, with the ship upright, in not less than 20 seconds and not more than 40 seconds. Both ends of that band matter. Too fast and the door becomes a guillotine for anyone in the opening; too slow and it does not close in the time the damage stability calculation assumes. If power fails, the door must still be closable by hand, and the hand-closing operation is allowed up to 90 seconds.

Three more numbers belong to the same test, and they are the ones crews most often cannot demonstrate. Before a remotely closed door begins to move, an audible alarm distinct from every other alarm in that space must sound for at least 5 seconds but not more than 10 seconds, and it must keep sounding until the door is fully closed. Every door must be operable by hand from both sides, locally, and that hand operation has to work with the ship listed — up to 15 degrees on a passenger ship, up to 30 degrees on a cargo ship. And at the bridge console there must be a diagram showing where every door is, with a red lamp for open and a green lamp for closed.

Test the indication properly, not by looking at the panel. Have somebody open a door locally and confirm the lamp on the bridge goes red without anybody touching the panel. Indicator circuits that have been wired out, lamps that have failed, and limit switches knocked out of adjustment by years of door movement are all common, and all of them mean the bridge is being told the ship is closed up when it is not.

Watertight door categories: which doors may be open at sea

The single most common watertight door finding is not mechanical. It is a door standing open that should not be, or a door with no indication of what its rules are. Doors are categorised by how they may be used at sea, and the category has to be visible on the door itself.

The operational rule underneath all of this is simple and is the one crews drift away from: doors kept closed at sea are closed, and the exceptions are for passage and for work in the immediate vicinity, both of which end the moment the person walks away. A door propped open with a fire extinguisher because the engine room is hot is not an exception. If your ship has doors that are genuinely awkward to keep shut, that is a design conversation with the technical superintendent, not a standing local practice.

Hatch cover inspection: the weathertight half of watertight integrity

On a dry cargo ship, the hatch covers are where watertight integrity is actually lost, and they are lost in a very specific place: the joint between the compression bar on the coaming and the rubber packing in the cover’s retaining channel. Everything else in a hatch cover arrangement exists to hold those two components in the right relationship to each other.

The packing is not supposed to be crushed flat. It is supposed to be compressed by a designed amount, and the landing pads — the steel bearing pads between cover and coaming — are what stop it going further. When landing pads waste down, the cover sits lower, the packing is over-compressed on every closing, and it takes a permanent set. When the packing has a permanent groove deeper than the maker allows, it no longer springs back, and the joint leaks at the first heavy weather. The usual discard rule is that the packing is renewed once the permanent set exceeds 50 per cent of the design compression, but the maker’s manual for your covers is the figure that counts.

Look at the compression bar itself while you are there. It has to be continuous, straight, free of corrosion pitting and not distorted by cargo gear or grabs. A bar that has been hit and bent locally will hold the packing off over that length no matter how good the rubber is, and the leak will be exactly there.

Hatch cover tightness testing: chalk, hose and ultrasonic

Three tests are in common use and they answer three different questions. Choosing the wrong one, or treating a chalk test as proof of weathertightness, is how ships arrive at a load port with covers that will not pass.

Whichever method you use, the output has to be a record with the hatch identified, the readings or observations against each section of the joint, the date and the person who did it. A test that produced no written result is, for inspection purposes, a test that did not happen — and it is the record, not the memory of the test, that a surveyor or a charterer’s inspector will ask to see. Keeping the readings against the hatch and the panel, rather than in a notebook, is what lets you see the joint deteriorating over three voyages instead of discovering it in one.

Watertight and weathertight inspection findings, and what each one means

The findings below are the ones that recur across fleets, ship types and PSC regimes. The middle column is the part crews tend to skip: what the finding is actually telling you about the system behind it.

Ship-specific limits always sit above this list. The maker’s manual for your hatch covers and the approved arrangement for your doors are the documents that decide numbers; this is the pattern, not the specification.

Permanent set, wastage and the watertight integrity renewal limits

Weathertight components are consumables with limits, and the limits are the part that gets lost when a ship changes hands or a maker’s manual goes missing. Three of them do most of the work.

The same discipline applies to portable securing gear: anything found in poor condition is marked and removed, not returned to the locker to be picked up by the next watch. A rack that contains a mixture of serviceable and rejected components is worse than a rack that is short, because the crew cannot tell them apart in the dark.

Coaming drains, non-return valves and progressive flooding

The coaming drain channel is the most misunderstood part of a hatch cover. It is not a seal and it is not a second line of defence in the sense people assume. It is a gutter, sized to carry away the small quantity of water that gets past the outer edge of the joint in normal weather, and to take it overboard through drains fitted with non-return devices.

Two things go wrong. The channel blocks, with rust scale, paint flakes and the remains of a previous cargo, and then it holds standing water directly against the packing on every roll. Or the non-return device fails or is removed, and the drain becomes a route for water to enter the hold rather than leave it — particularly on a deep-laden ship where the drain outlet is periodically below the waterline. Both are visible with a torch, and both are quick to fix; neither is fixed by anybody who has not been told the channel is a system rather than a gap.

The same logic runs through the rest of the weathertight envelope. Air pipe heads have floats that stick and gauze that blocks. Ventilator closing appliances have butterfly nuts that seize open. Sounding pipe caps lose their gaskets. None of these is dramatic on its own, and all of them are openings in the boundary you are certifying as weathertight. Treat them as a single walk-round with a list, not as things you notice when you happen to be passing — the same way you would run a hold preparation round before a survey.

Watertight integrity drills, operation and the records inspectors read

The operational regime is where watertight integrity becomes routine rather than an event, and it is where the evidence comes from. Passenger ships carry the heaviest requirements — a watertight door drill weekly, doors in use at sea operated daily, and the doors and their mechanisms inspected weekly — but the pattern is worth applying on any ship with power-operated doors.

What an inspector is reading in those records is consistency. A log with an entry every week for six months, including the weeks when something was found wrong, is far stronger evidence than a log with perfect entries and no defects ever recorded. The second one reads as a form being filled in.

Did anything change for watertight integrity in 2026?

No. It is worth saying plainly, because the question comes up on every ship at the moment and because a good deal of the material circulating implies otherwise. The SOLAS amendment package that entered into force on 1 January 2026 does touch chapter II-1, but the substantive addition there is regulation 3-13 on lifting appliances and anchor handling winches, together with the supporting definitions in regulation 2 — not watertight doors, not subdivision, not openings, not damage control.

The requirements in this guide — the closing times, the indication, the categories and signboards, the hatch cover regime under the Load Line Convention — are unchanged. If you are working through the 2026 package for your ship, the watertight integrity chapter of it is short, and the work in that package sits elsewhere — most of it in the new lifting appliance requirements, which do reach every ship with a crane.

Watertight integrity deficiencies and detention risk

Watertight integrity findings do not get their own line in the published statistics; they sit inside the SOLAS chapter II-1 category, which covers structural and electrical elements together. That category is consistently the second-largest source of deficiencies in the Paris MoU region.

The number worth carrying away is the detention rate rather than the deficiency share. It rose to 4.18 per cent in 2025 from 4.03 per cent the year before, across 16,474 inspections and 51,797 deficiencies, with 688 ships detained. Closing appliances sit near the detainable end of that distribution precisely because they are operational: a door that does not close, or an indication system that does not indicate, is not an observation an officer can write up and leave — it is a defect in a system the ship’s survival calculation depends on. Fire doors, as a comparable item, accounted for 3.1 per cent of individual deficiencies on their own, and the same discipline that keeps them working is what the fire safety inspection regime is built around.

The week before a watertight integrity inspection

Watertight integrity inspection: frequently asked questions

Related guides on this site: cargo securing and lashing equipment inspection and running it all through the ship’s planned maintenance system.