HOW TO CLEAN A BOAT HULL

How to Clean Your Boat Hull – August Race Guide

Keeping your boat’s hull clean is one of the most important parts of regular maintenance. Not only does it improve performance on the water, but it also gives the opportunity to inspect for damage that could potentially lead to water ingress (osmosis)

Whether you’re new to boating and still learning the terminology, or you’ve been sailing for years, cleaning the hull should be high on your maintenance list.

Understanding Your Boat’s Hull

For anyone unfamiliar with boating jargon, the hull refers to the main body of the boat — from the bottom of the keel (the lowest point under the water) up to the rubbing strake, which is the protective strip around the outside.

Other terms worth knowing:

  • Topsides – The section between the waterline and the deck edge.

  • Superstructure – Everything above the deck, such as the cabin or wheelhouse.

Why a Clean Hull Matters

Over time, hulls accumulate algae, slime, and limescale deposits, especially in freshwater. In seawater, you also get salt and mineral buildup. This not only spoils the appearance of your boat but can also cause:

  • Increased drag (reducing speed and fuel efficiency)

  • Staining around the waterline

  • Potential long-term damage if deposits are left untreated

When and How Often to Clean

There’s no single “best time,” but many boat owners schedule a full hull clean when their vessel is lifted out for winter storage and again in early spring before the new season. Mid-summer touch-ups can also help keep algae and limescale at bay.

Hull Cleaning Step-by-Step

For best results, the boat should be lifted out of the water. Here’s our recommended process:

  1. Lift the boat – Use a marina hoist or trailer to bring the boat out safely.

  2. Pressure wash – Rinse away loose growth and staining beneath the waterline.

  3. Scrub – Use a SWOBBIT brush or scrub tool to agitate any growth and rinse a second time.

  4. De-Stain – The best way to remove staining from a boat hull is to apply August Race Bright Coat and leave to activate. Bright Coat will remove yellow staining from the hull and leave it looking clean

  5. Reviving Faded GRP - Use a polishing machine apply August Race® Super Fast Cut Polishing Compound to the surface and working in small areas gently polish until the desired finish is achieved.

  6. Protect - Apply August Race Smooth Opacity UV protective UV polish as per the instructions and buff to a high shine finish

  7. Seal - Finish with a complete hydrophobic coating using August Race Cera-Marine ceramic sealer coating

 

Environmental Tip: Always carry out cleaning in an area where runoff water can be contained and filtered, especially when using acidic cleaners.

 

Products & Tools You’ll Need

 

Cleaning While Afloat

To avoid harming aquatic life and the environment you should never apply cleaning products while afloat and you can’t deep-clean the entire hull without lifting the boat, but you can tidy up the waterline using the professional grade Perfect Pole™  with the 7.5″ Soft Flagged Brush Attachment

Special Considerations

  • Fibreglass hulls – Respond well to compounding and waxing to restore gloss.

  • Wooden hulls – Avoid pressure washers; use a soft brush to protect caulking and timber.

  • Saltwater boats – Rinse with fresh water regularly and use August Race® Boat Wash Pro to prevent salt staining.

 

 

Professional Hull Cleaning

A full professional clean for a 20–25 ft boat typically takes around four hours, including lifting, pressure washing, polishing, and waxing. If you would like to discuss becoming a professional boat valeter visit the August Race Training Hub and fill out the form to book onto one of our courses.

 

August Race offers a complete range of marine-safe cleaning products to help you keep your boat looking its best — whether you’re tackling the job yourself or working with a professional detailer.