Boat & Marine Detailing

You can, and it'll look good for about a fortnight. Gelcoat is a different surface to car paint. It's thicker, softer, porous, and it has no clear coat over it, so it oxidises into a chalky white haze under UV, absorbs stains, and cops salt, algae and bird droppings that a car never sees. Car polishes are too fine to cut chalked gelcoat efficiently, and car waxes break down in weeks under salt water and full sun.

Marine products are formulated for that. Gelcoat compounds like the Koch Chemie Gelcoat range are coarser and wetter so they cut oxidation without loading up. Marine waxes like Collinite 925 use harder carnauba and polymer blends that survive salt, UV and constant wet-dry cycles for a season rather than a month. The difference is durability, and on a boat that's the whole point.

Rinse the salt off first, always, and do it as soon as the boat is out of the water if you can. Dried salt is abrasive and it holds moisture against the gelcoat. Then wash with a pH neutral boat wash, which lifts grime without stripping whatever protection is on there. For the waterline scum, algae and the brown staining that builds up over a season, step up to a dedicated boat cleaner or a fibreglass cleaner with a bit of bite, and for mould in the seams and on the vinyl a mould and mildew cleaner.

Work in shade, keep it wet and rinse before it dries. Gelcoat is porous, so anything strong that dries on it tends to stay there.

Same ladder as paint, just coarser. Chalked gelcoat needs a heavy cut compound on a wool or firm foam pad with a rotary or a big DA, and it takes real work, so plan on a full day for a mid sized hull. Start with a test section. If a heavy cut like Koch Chemie Gelcoat Heavy Cut or Rupes Marine G-Coarse brings the colour and gloss back, follow with a fine cut or a gelcoat finish polish to clear the haze. If the oxidation is light, an intermediate like Gelcoat One Cut or Wake Up Marine AIO might do it in one step and leave protection behind.

Keep the pad wet and the speed moderate. Gelcoat builds heat faster than paint, and it can be burnt. Wipe down with a clean towel between steps so you can see what you've actually done. Our polishers and wool pads cover the machine side.

Wax is the traditional answer and it still works. A hard marine paste like Collinite 885 or the liquid 925 is easy to apply, cheap per season, and it's what most boat owners reach for every spring. Expect a few months of beading before it needs redoing, less on a boat that's in the water full time or in the sun all day.

A marine ceramic coating like CARPRO Nautik or Beadlock Pro is the step up. It bonds to the gelcoat, holds up to salt and UV for a year or more, and makes the waterline scum rinse off instead of needing a scrub. It costs more and the gelcoat has to be properly polished and clean before it goes on, but on a boat you use a lot, the time it saves cleaning pays for it.

The vinyl. Seats, cushions and bimini tops crack, fade and go mouldy well before the hull does, and they're the expensive bit to replace. A UV vinyl conditioner after each clean keeps them soft and stops the fading. Stainless rails and fittings pick up tea staining from salt, a metal polish deals with that. Clears and screens need a plastic safe cleaner, not a glass cleaner with ammonia in it. And if you get water spots from a hose down or a hard water wash, a marine water spot remover lifts them before they etch.