How to clean a bulk carrier cargo hold: the full procedure, step by step

What hold cleaning actually is (and why it matters)

Bulk carrier hold cleaning is the work of getting a cargo hold from "just discharged" to "fit for the next cargo." That covers removing residue of the previous cargo, loose rust and paint flakes, dust, stains and moisture, and in some cases odour and chlorides too.

Why bother? Because the next cargo decides whether the ship earns money. Grain, sugar, fertiliser, cement and alumina all need a clean, dry hold, and a surveyor will check before a single grab is loaded. Fail that check and the ship can go off hire while it re-cleans, lose its place in the berth queue, or in the worst case lose the fixture. Contaminate a cargo and the claim that follows makes the cleaning bill look like pocket change.

There's also a maintenance reason people forget. You can't inspect a hold you can't see. Residue hides cracked frames, wastage and damaged coating, and a hold that's never properly cleaned is a hold whose condition nobody actually knows.

When should cargo holds be cleaned?

The short answer is as soon as the last grab comes out. Residue is easiest to remove while it's still loose and before it's been baked on, soaked or set hard. Cement is the extreme case (wait too long and you're chipping instead of washing), but the same is true to a lesser degree of almost everything.

Industry guidance, including The Swedish Club's practical guide, puts it plainly: preparation starts on completion of discharge whether the next cargo is fixed or not. If you don't know what's coming next, the sensible default is to clean towards grain standard, because that's the one most cargoes ask for.

Step 1: Plan before anyone picks up a broom

A surprising number of failed inspections are planning failures. Before the work starts, the Master and Chief Officer should know:

• The next cargo and the required standard. Get it from the voyage instructions or the charterparty, not from a phone call. "Clean holds" means nothing; "grain clean, USDA inspection at the load port" means a lot.
• The previous cargo and its properties. Is it classed as harmful to the marine environment (HME)? Does it stain? Does it set? Does it give off gas?
• Where you'll be when you wash. MARPOL Annex V and local port rules decide where wash water can go. Some ports don't allow any washing alongside.
• Fresh water on board. You'll need a lot for the final rinse. More on that below.
• Chemicals, equipment and people. If the job needs a petcoke degreaser and you have half a drum of general-purpose cleaner, you need to know now, not at the load port.

Write the plan down. Holds in order, people per hold, start times, the point at which the shore office gets told if things slip.

Step 2: Get the bulk of the residue out during discharge

The cheapest residue to remove is the residue that never stays on board. Ask the stevedores to sweep down and clear trapped cargo from ledges, ladders and hopper tops before discharge finishes, while there's still a grab or a bobcat in the hold to take it ashore. Every tonne that leaves with the cargo is a tonne you don't have to sweep, bag, lift and dispose of later.

Step 3: Clean the hatch covers and coamings first

Start at the top, and start outside the hold. Hatch covers, coaming tops, cross-joints and drain channels collect cargo, and whatever's up there will end up on your freshly cleaned tank top if you leave it. Sweep the coamings and clear the drain channels before washing anything. Britannia's guidance specifically advises against blowing debris out of channels with compressed air, since it just redistributes it.

Step 4: Dry sweep the hold, top to bottom

Should a hold be dry swept before washing? Almost always, yes. Washing a hold full of loose residue turns it into slurry, chokes the bilges and multiplies the volume of dirty water you have to deal with.

Sweep from high to low: ladders, platforms and hopper tops first, then the tank top. Pile the sweepings, bag or bucket them out, and record what you remove. The exception is sulphur: the IMSBC Code says holds that carried sulphur shall not be swept, because the dust is a hazard. That's covered in its own procedure.

Step 5: Clean the bilge wells before you wash

It sounds backwards, but clear the bilge wells and strainer plates of solid residue before the main wash. If you don't, the first wash sends mud straight into a well that's already half blocked, and you'll be bailing it by hand at midnight. Once they're clear, check that the bilge suction actually works.

Step 6: Wash down with seawater, top down

With the loose material gone, wash the hold. For straightforward water washing, work from the top down so dirt runs onto areas you haven't cleaned yet, not onto areas you have. A sensible order is:

1. Underside of the hatch covers and the coamings
2. Under-deck area and upper parts of the bulkheads
3. Upper hopper tanks and upper side frames
4. Side shell and transverse bulkheads
5. Lower hoppers
6. Tank top
7. Bilge wells, last

Upper frames and inaccessible areas are where most holds are won or lost. A high-volume combi-gun from the fire main can reach a long way, but a jet at 15 metres has lost much of its punch. If the residue is stubborn up there, you either need a high-pressure lance brought closer (cherry picker, staging or rope access) or a chemical that does the work before the water arrives.

Step 7: Chemical cleaning, if the residue calls for it

Water removes dust. It doesn't reliably remove the oily film petcoke leaves, coal stains, or set mineral fines. For those you need a hold-cleaning chemical matched to the residue and compatible with the hold coating.

Two rules matter more than any brand. First, follow the manufacturer's instructions on dilution, dwell time and application order. Some chemicals are applied bottom-up on a dry surface, which is the opposite of how you water-wash. Second, don't let the chemical dry on the steel. Apply it, give it the contact time it needs, then wash it off with high pressure before it skins over.

Step 8: Fresh water rinse

When should fresh water be used? At the end, every time a hold is being prepared for a cargo that cares about chlorides, which is most of them. Seawater leaves salt behind. Salt attracts moisture, attacks coatings and can make a perfectly dry-looking hold fail a silver nitrate test, which then muddies any later argument about whether water got into the cargo.

Rinse the whole hold, top to bottom, ideally before the seawater has dried, while the salt is still easy to move. Flush the fixed washing lines through with fresh water first, or your "fresh water rinse" is just more seawater. Many bulk carriers carry rinse water in the aft peak or a dedicated tank for exactly this reason.

Step 9: Dry and ventilate

Drying is a stage, not something that happens while you're doing something else. Open the hatches if it's safe to do so, run mechanical ventilation if you have it, squeegee standing water off the tank top and pump the bilge wells dry. In humid weather or in the rains, a hold left to dry by itself may not dry at all inside the time available. Plan the holds you finish first to get the longest drying time.

Step 10: Pre-inspect like a surveyor would

Before anyone calls the surveyor, the Chief Officer should walk every hold with a powerful torch and a scraper. Look at the places nobody sweeps: behind brackets, under ladder rungs, on top of pipe guards, inside the bilge wells, along the hatch cover undersides. Tap suspect rust with a scraper. Sniff. Run a hand along a frame flange. If you find something, it's still your problem and not a reason for off-hire.

Then cover the bilge wells as the cargo requires (burlap for grain is common), test the bilge suctions and close up.

How long does it take, and how many people?

It depends heavily on the previous cargo, the standard required and the size of the ship, which is why we've written a separate guide on hold cleaning time. As a rough rule, sweeping and washing a lightly soiled hold is a day's work for a small team. Taking five holds from coal or petcoke to grain clean is several days for a ship's crew that also has to keep watches, and that's where a shore gang or a riding crew usually earns its money.

The short version

Plan from the next cargo backwards. Get residue out during discharge. Sweep before you wash. Clear the bilges early. Wash top down. Use the right chemical, the right way. Finish with fresh water. Dry properly. Inspect as if you were the surveyor. Skip any one of those and the hold will tell on you.

If you'd rather hand the whole thing to a team that does it every week, talk to us before the vessel arrives. The earlier we know, the less port time it costs.