A yacht comes back from a season on the water carrying a mix of deposits that no single setting removes: salt crusted along the hull and through the waterline band, polymerised sunscreen and deck-grease films on the toe rail and hardware, algae and biofouling on the boot stripe, rubber marking on the non-skid, and grease smear around the cleats and winch bases. Before any steam wand touches that surface, the operator's first job is not to choose a setting. It is to write down what the surfaces actually are, which of them the work will not be done on, and what has to be true before the job counts as finished.
Start with the surface list, not with the machine
On a pleasure craft the exterior is not one material. It is a laminated gel-coated hull, an alloy or stainless superstructure, anodised or powder-coated trim, varnished spars on older boats, teak or synthetic decking, moulded non-skid, vinyl upholstery and canvas, rubber fender and rubrail surfaces, and a run of through-deck fittings with seals and fasteners. Each one answers heat and water differently, and each one is fixed in place: unlike a car panel, none of it can be taken into a bay and worked flat. Write the list area by area, and against each area record the finish condition, how old the deposit looks, whether the surface is vertical, horizontal or above head height, and how close the nearest opening is. That list is what makes the rest of the operator briefing meaningful.
Where a finish has already failed, note it before the job rather than after it. Chalking or blistering gel coat, crazing, a lifting edge on a decal, a crazed or repaired windshield, an old repair seam, a hairline in a rubrail: all of these are pre-existing conditions, and recording them with photographs dated before the first pass protects the operator as much as it protects the owner.
Know the exclusion list before the first pass
An experienced operator works from a written exclusion list as much as from an instruction list. On a yacht the items that normally sit outside the working area include sealed deck seams and bedded fittings where the sealant has aged, windscreen and window edges and any glazing with an edge seal or an old repair, anodised trim with a printed or dyed finish, decals and vinyl lettering, varnished timber, canvas and spray hood material, upholstery and its piping, bow-roller and anchor gear where grease is deliberately present, rubber dinghy surfaces, and anything above or beside the water intake, through-hulls, transducer and anode positions. Each excluded item needs a stated fallback in writing, so the job is still completed by other means rather than simply left undone.
Some exclusions are not the operator's call at all. Whether work may be done afloat or must be done on the hard, where the run-off may go, and whether the mast, rigging or through-deck gear may be worked around belong to the yard, the marina and in many cases the flag or class authority. These answers should be in the paperwork before the shift starts, not settled at the berth.
Match the deposit to the mode, not to habit
Heat, dwell time and the amount of water actually applied do different jobs. A dry, low-moisture pass is the usual starting point for a grease or sunscreen film on hardware and for breaking the bond of rubber marking on non-skid, because it lifts the film without flooding the surface. A wetter pass suits encrusted salt and dried organic matter on the hull and on through-deck gear, where the deposit has to be rehydrated before it will release. A hot-water rinse is the sensible closing step where detergent residue or loosened soil has to be moved off before the surface is dried. Biofouling on a boot stripe is its own problem: the growth has to be removed and collected before heat is applied to the surface beneath it, and on some coatings that step is restricted entirely.
The mode names come from the machine. mobile steam cleaning machine listings for this range describe dry steam, wet steam and hot water as the three modes, while other models in the same catalogue publish only a dry and wet switch. Which modes are actually available on the unit standing on the quay changes the sequence an operator can plan, so the mode list has to be read off the machine being hired or bought, not assumed from the brochure.
Decide the power question before you arrive
There are two ways to bring heat to a hull, and they are decided by different constraints. Afloat work means a unit that carries its own energy store and works away from shore power, which puts the limits on how long a charge lasts, how it is recharged, and how the unit is moved up and down a pontoon. On the hard or in a yard, the site supplies power and water, which puts the limits on where the circuit is, what the inlet arrangement is, and how far the operator must walk to refill. Those are site facts, not catalogue facts.
Ask the supplier to state, for the exact machine being quoted, the working voltage and heating arrangement, the water feed and tank arrangement, the inlet fitting and thread, the mobility and footprint, and the protection functions together with what happens when one of them trips mid-job. The published page for Fixed Steam Cleaning Machine PowerDe HW02 records a fixed machine intended for vehicle-type duty; a tank figure on a datasheet is a tank figure, not a working time, and heat or pressure values recorded for one model cannot be transferred to another. Marine work is not written on those catalogue pages as an application, so a yacht duty is proven on the boat, not on the datasheet.
Never open with a pass on the visible hull
The first working area should be an expendable or inconspicuous one: a loose rubrail section, a stowage-lid underside, a spinnaker-tube length below the deck line, or a sample panel taken from a scrapped part of the same laminate. Mark two or three patches with tape, photograph each one before work starts, and treat them as the record. Move the wand continuously, keep a working distance that is stated in the operator briefing rather than improvised, and stop at the first sign of lifting, blistering, sealant softening or colour change.
Judge a patch only once it has dried, and let the verdict come from a person who never held the wand. Wet surfaces flatter a finish and hide the two failures that matter: a lifted edge somewhere the heat reached, and a deposit left behind in a texture that a glossy wet surface disguises. Write the pass or fail condition before the trial, in words the owner can read, rather than agreeing the result afterwards.
Work the way water travels downhill
The order of work on a boat is not decorative. Start high and move down: superstructure and mast base areas first, then the cabin top and coachroof, then the deck and non-skid, then the toe rail, then topsides, then the boot stripe and below. Anything worked above will run down across an area already finished, so an overhead or high pass always carries a re-clean of the area beneath it in the plan. Water finding its own path is also the reason the deck gear, chain lockers, stanchion bases and deck drains get attention: soil and rinse water sit in them long after the visible surface looks clean.
Plan the rinse-off route as part of the task. On a berth, run-off from a hull carries antifouling residue, oil, and whatever the deposit was; where it may go is a marina and environmental question, and a containment or collection step is a cost that belongs in the quote rather than a decision made by the person holding the lance.
Finish on a return-to-service condition, not on appearance
A job is closed when the written conditions are met, and those conditions should name them: the surface dry, the deck-gear cavities and drains clear and dry, the exclusions confirmed untouched, seals and through-hulls checked as they were found, the deck non-skid free of residue so it is not slippery, and any area worked above re-worked after the run-down. Then record the trial patches, the photographs, who judged them and who signed the result. Where the trial shows a limit, that limit becomes part of the next written instruction for this class of boat.
Operators who keep that record, listing per area, are the ones whose judgement survives a change of crew or a change of boat. If the duty keeps recurring across a fleet, ask about customized steam cleaning equipment with the areas, exclusions and utilities you have already written down, and let the trial patches on your own boat decide the answer.
