Few things irk me more than dirty, chalky and stained gelcoat. Like an engine that is corroded – or lines that are chafed – worn gelcoat is a sure sign of neglect.

Fortunately there are multiple ways to restore aged, stained, dirty and faded gelcoat. With a bit of care and a lot of elbow grease, the methods here are guaranteed to drastically improve the appearance of your craft.

1. Cleaner wax/polish

A boat that looks like this needs only a ceramic coating, paste wax, or PTFE polish

Tools and materials

This is the simplest and least laborious of the three methods, but only applies to newer boats with surface stains, minor fading and discolouration of the gelcoat, and little to no oxidation.

To determine if gelcoat is oxidised, wipe your hand across the surface. If any ‘chalk’ wipes off on your fingers, the gelcoat is oxidised and will need to be washed and buffed before polishing. If you are lucky and all your boat requires is a light polish, here’s what you need to do:

Step 1: Gather your supplies: you’ll need a pack of high quality microfibre towels and a polish. Low quality towels will shed fibres and leave streaks and residue.

For boats with slightly more deteriorated or faded gelcoat, a hull cleaner or restoring boat wax may be chosen – 3M and other brands make a good quality product that can be used for this purpose.

For boats that have only minor gelcoat defects or staining, a polish such as Shurhold’s Pro Polish can be used. I’ve found that polymer polishes work much better than carnuba waxes at sealing the pores in gelcoat and producing a durable high gloss finish. Polymer polishes can last up to a year, while even the best boat waxes generally only last for a few months at a time.

Step 2: Wet the microfibre rag, wring it out and then apply a tablespoon of polish to the rag. This amount of polish will work for a few square feet.

Before buffing, spread the polish evenly across the boat’s gelcoat. It’s best to work in small areas and work the polish into the surface with a circular motion and lots of leverage. A buffer with wool pad may be used at low speed, but I prefer to buff by hand as it’s much more precise and easy to get into nooks and crannies.

Step 3: When the polish dries into a haze, remove it with a clean, dry microfibre rag. Be sure to apply adequate force or a film of swirl marks will remain. Be sure to get in all the nooks and crannies or they’ll be an eyesore.

Note: In the past I’ve cleaned and polished non-skid decks with polymer polishes, which made my deck highly reflective. It did, however, make the deck a bit more slippery so I’d advise using a product made especially for this part of the boat. The best way to polish non-skid is with a wetted bristle brush. Simply scrub the polish on and then wipe it off with a dry microfibre towel.

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2. Compound and polish

Our Chaparral 2335 after an initial polish

Tools and materials

• Pressure washer: £140
• On/Off hull cleaner: £20 per litre
• Disposable gloves and goggles £10
• Wool polishing bonnet: £30 each
• Spare wool polishing pads: £15 each
• Shurhold Buff Magic (624g/22oz): £22
• Polymer varnish (varies)

For boats 10-20 years old that have been left out in the elements, this is the most likely method for restoring appearance. Boats in this category will be oxidised and have many stains. While experts may tell you to wet sand your boat with 600-1200 grit depending on the severity of the oxidation, I have found it unnecessary. Instead, I follow the steps below:

Step 1: Clean the surface. While dish soap or a degreaser may work, it is best to use a pressure washer with approximately 2000psi and an acid wash to remove any stubborn and deep staining. For this task, I like On/Off hull cleaner, but hand and eye protection must be worn when dealing with any acidic solution.

Step 2: Once the hull has been acid washed and pressure cleaned, you will notice it is now clean – albeit dull. A hand buff with a buffing mitt or microfibre towel for heavily oxidised boats is difficult though do-able. A rotary buffer wool bonnet is much better.

The same boat’s gelcoat after multiple polishes – it is important to polish every few months

Note: Be careful not to burn through the gelcoat by working one spot too long. When buffing be sure to use a good quality rubbing compound.

I’ve had good results with most marine compounds including those offered by 3M and Meguiar’s, but my best results have been achieved with Buff Magic by Shurhold. Work on small 3-5ft sections of the hull at a time.

While buffing, the wool pad must be damp. After working the material into one area, you’ll notice that the pad is dry and the wool matted.

When this occurs, rake the wool back into form with a pad spur and re-wet the pad. It’s prudent to change the wool pad frequently.

Step 3: After the boat has been compounded to satisfaction, follow up with a polymer polish to chemically seal the now glossy and clean gelcoat.

3. Wipe-on acrylic sealer

Tools and materials

• Pressure washer: £140
• On/Off hull cleaner: £20 per litre
• Zep High Traffic Commercial Floor Polish: £20 for 5 litres
• Terry towels: £10 per box

While lamenting the heavily worn and stained gelcoat of my 1987 Ericson 38 yacht, I began to research alternatives to painting. As gelcoat ages, it becomes porous and therefore deeply ingrained with stains, but because we were in the midst of a refit, with too much else to do painting was entirely out of the question.

So something else had to be done about our boat’s ghastly outward appearance, which at a dusty boatyard acted like a sponge to soak up every contaminant into its large pores. I tried this method as a last ditch effort and, so far, it has completely rejuvenated our old gelcoat!

Our Ericson 38 stained hullsides before…

…and after coating with Zep floor polish

Step 1: Clean with a pressure washer and an On/Off acid wash to remove embedded stains.

Step 2: We decided to go with Zep Wet-Look Commercial Floor Polish over the more expensive boat polishes. While you may or may not have better results with one of the more expensive options, we are satisfied with Zep, which cost a mere £20 for 5 litres.
While the instructions recommend application via mop, we decided to use terry towels for a more precise application.

Step 3: Four initial coats are recommended, allowing at least 30 minutes of drying time between coats. Since Zep soaks in to the pores of gelcoat and forms a hard, clear acrylic layer over the gelcoat, preparation is vital for satisfactory results.

Unlike buffing or polishing – which remove imperfections the more you buff – an acrylic sealer seals in all imperfections so be certain you remove all surface contaminants, bugs and runs before the polish dries or they’ll be sealed in until the surface is stripped – a very tedious process.

Over the course of a few days we applied four coats to our boat’s hull and topsides and were really impressed with the results.

To maintain the finish it’s advisable to reapply at least one new coat a year. If you lapse the finish will bubble and peel off, making it necessary to strip the whole surface with a proprietary stripper before re-coating.

Acrylic sealer will not make your boat look perfect, but it will breathe new life into ancient gelcoat.