By Capt. Neeraj Bharti, Founder, Master Mariner · Published · 2 min read
How long does a DPP to CPP changeover take? What drives the timeline
"How many days?" is the first question every operator asks about a changeover, and the honest answer is that it depends on factors you can mostly know in advance. Once you know them, you can estimate with reasonable confidence and decide whether the time available is enough.
What drives the timeline
The cargo pair. Fuel oil to gasoil is a shorter job than fuel oil to jet or naphtha. Crude can be different again. The more sensitive the next grade, the more washing, finishing and verification.
Number and size of tanks. More tanks mean more washing cycles and more manual finishing, though tanks can be worked in parallel.
Residue and sludge. Tanks with heavy sediment may need demucking before washing can work.
Heat. Hot washing removes fuel oil far faster than cold. If the ship cannot heat wash water, expect a much longer job.
Coating. Good coating cleans faster. Old, porous coating needs more work and may still stain.
Lines, pumps and coils. Flushing and draining the whole cargo system takes time that is often left out of estimates.
People. The crew alone, working around watchkeeping, will be slower than a dedicated riding squad or shore gang.
Drying and gas-freeing. Mopping, drying, ventilation and gas-freeing for manual work all take hours per tank.
Inspection. A failed inspection adds a day or more.
Where to do it
A ballast passage of several days is often the best window: washing and manual work run while the ship is moving, and no port time is lost. Anchorage work suits ships with a waiting period. Alongside is usually the most expensive time to be cleaning.
How to shorten it
- Plan before the ship starts. Cargo pair, standard, coating and slops agreed in advance.
- Wash hot. Heat is the biggest single time-saver after dark cargo.
- Work tanks in parallel, with enough people to do manual finishing behind the machines.
- Include lines and pumps in the schedule rather than leaving them to the end. See lines, pumps and heating coils.
- Pre-inspect. Catch problems before the inspector does.
- Add a riding squad when the passage is short and the job is large.
Estimating for your ship
The best estimate comes from someone who has seen the ship's tanks and history. Rough rules give false comfort. Send us the vessel, tank count, cargo history, next grade, coating condition, heating capability and the window available, and we will give a realistic duration. See the DPP to CPP changeover guide and failed tank inspection after a changeover.
How Cleanship helps
We provide riding squads and shore gangs for changeovers from Fujairah and Indian bases. See our DPP and CPP tank cleaning service or contact our operations desk.
Sources & further reading
Frequently asked questions
How long does a DPP to CPP changeover take?
It depends on the cargo pair, number of tanks, residue, heating, coating, lines and pumps, people available, drying and gas-freeing, and inspection. A realistic estimate needs those details for the specific ship.
Can a changeover be done during a ballast passage?
Yes, often. A passage of several days lets washing, manual finishing and drying run while the ship is moving, with no port time lost.
What is the biggest time-saver in a changeover?
Hot washing after dark cargo, combined with enough people to work tanks in parallel and a plan agreed before the work starts.
Why do changeover estimates often run over?
Because lines, pumps, coils, drying, gas-freeing and inspection are left out of the estimate, or sludge and coating problems are discovered late.
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