Short answer
It's done in four steps. You wash, cut away the oxidation with an abrasive compound, polish with a finer compound and finally wax. Dull, chalky gelcoat needs compounding. A boat that is already glossy only needs wax. Wax at least once a season, ideally before launching.
What you need
| Step | Product | Tools |
|---|---|---|
| Wash | Boat shampoo | Sponge, soft brush |
| Compounding | Coarse compound | Rotary polisher, wool pad |
| Polishing | Fine polish | Dual action or rotary polisher, foam pad |
| Protection | Wax or polymer/ceramic | By hand or by machine at low speed |
Change pads between steps so the coarser product isn't carried into the next one.
Step by step
- Wash and rinse off salt and dirt. Sand in the pad causes new scratches.
- Tape over decals, rubber strips and teak.
- Work half a square metre at a time with a little compound and moderate pressure. Do not let the machine sit still on edges.
- Wipe with a clean microfibre cloth and inspect the surface in low-angle light.
- Polish with a finer compound until the surface has a deep gloss.
- Wax, and buff once the wax has dried for as long as the packaging says.
Common mistakes
- Working in direct sun. The product dries and smears.
- Rubbing too hard on edges, where the gelcoat is thin.
- Waxing the antifouling or the non-slip on deck. It gets slippery.
- Forgetting that the wax must be cleaned off with acetone before you repair gelcoat.
Oxidation, chalking and yellowing
UV light breaks down gelcoat. The surface first turns dull and then chalky, so your finger comes away white when you run it over the hull. Dark hulls and older boats are hit hardest. Here is where to start:
| Surface condition | Start with |
|---|---|
| Glossy, just dirty | Wash and wax |
| Slightly dull | Polish and wax |
| Chalky, white on your hand | Rubbing compound, polish and wax |
| Deep scratches | Wet sanding, then rubbing compound |
| Yellowed waterline | Waterline cleaner before polishing |
Do a test patch first and start with the least aggressive product. If polish doesn't bring back the shine, go one step coarser. Material you have removed won't come back.
Work from the top down: superstructure, deckhouse and the hull sides last. Change or wash the pads often. A clogged pad heats the surface and leaves holograms. Stop a little short of taped edges and do the edges by hand. It helps to note which products worked, so the job goes faster next year.
DIY or order
Many yards polish the boat in connection with launching. Get quotes from a few yards and compare. More spring jobs are in the spring commissioning checklist.
Frequently asked questions
How often should you wax your boat?
At least once a season. A boat kept in the water in strong sun benefits from two treatments.
Do I need a polisher?
Hand application is fine for wax. To remove oxidation you'll in practice need a machine.
Is ceramic coating better than wax?
It often lasts longer, but the prep work has to be more thorough. Follow the instructions on the product.
Can I polish the boat while it's in the water?
The superstructure and deck are fine. The hull sides are much easier and safer to do when the boat is ashore before launch. Water and wash make it hard to work with a machine.