By Capt. Neeraj Bharti, Founder, Master Mariner · Published · 2 min read
How long does underwater hull cleaning take? The factors that decide duration
Operators usually want to know one thing before booking a hull clean: will it fit the port call? The answer depends on a handful of factors that can be known in advance. Here they are, so you can judge whether the window is realistic.
What decides duration
Hull area. The wetted surface to be cleaned is the base. A Capesize has far more than a Handysize.
Fouling level. Slime comes off quickly. Heavy barnacles after a long wait at anchor can take several times longer per square metre.
Niche areas. Sea chests, gratings, thruster tunnels, bilge keels and the rudder are slow hand work. Including them adds time out of proportion to their area.
Propeller. Polishing is a separate stage, usually hours rather than days.
Team size. More divers and carts mean faster work, within the limits of safe diving operations.
Conditions. Visibility, current, swell and tide decide how many productive hours divers get. Strong tidal ports need diving around slack water.
Daylight rules. Some ports allow only daytime diving, which can stretch a job over more days.
Permissions and isolations. Waiting for permission or isolations costs time before cleaning even starts.
Typical ranges
As a rough guide, a straightforward clean of a mid-sized ship with light to moderate fouling, in good conditions, can often be completed within a day or so of working time, and propeller polishing within hours. Heavy fouling, large ships, extensive niche areas and difficult conditions can extend that significantly. These are planning ranges, not promises; the real figure comes from the specific ship and port.
How to shorten it
- Inspect or share photos first so the right team and equipment are sent.
- Prepare isolations before the team arrives. See preparing a vessel for hull cleaning.
- Arrange permissions early.
- Clean more often. Light fouling is quicker to remove than heavy growth.
- Combine jobs (hull, propeller, niche areas) into one mobilisation.
Fitting it into the call
If the window is shorter than the job, the options are a bigger team, a reduced scope (for example flat bottom and propeller first), or cleaning at a port where the ship will wait longer. See hull cleaning at anchor vs alongside.
Cleanship
Send us the vessel, port, window and any photos, and we will give a realistic duration. See our underwater hull cleaning service or contact us.
Sources & further reading
Frequently asked questions
How long does underwater hull cleaning take?
It depends on hull area, fouling level, niche areas, propeller polishing, team size, conditions, daylight rules and permissions. A straightforward job on a mid-sized ship in good conditions can often be done in about a day of working time.
How long does propeller polishing take?
Usually a matter of hours for a typical merchant ship propeller, depending on size and condition.
Why do some hull cleaning jobs take longer than planned?
Heavy fouling, poor visibility or strong current, daylight-only rules, isolations not ready, or permissions arriving late.
Can hull cleaning be done in one day?
Often, for a mid-sized ship with light to moderate fouling in good conditions. Larger ships or heavy fouling may need longer.
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