16th Jun 2025
Boat fenders are vital for protecting your vessel from impact damage during docking and rafting, but they’re also some of the dirtiest pieces of equipment on board. Constantly exposed to grime from docks, algae from the water, oily residues from harbours, and black marks from rubbing against hulls or marina walls, fenders can quickly go from bright and professional to grubby and neglected. Fortunately, with a little knowledge and the right techniques, cleaning your boat fenders is straight forward - and makes a noticeable difference to your boat’s appearance. In this guide, we'll take you through how to clean, restore, and maintain your fenders so they stay looking smart and performing well for longer.
The first step is to assess the level of dirt or staining. Light dirt, salt deposits, and scuff marks can usually be dealt with using general boat soap or a mild detergent. More stubborn black marks, oil stains, or deeply ingrained grime may require a more intensive approach, including specialist cleaning products or even light abrasion. It’s always best to start with the gentlest method and escalate only as needed to avoid damaging the surface of the fender.
Before cleaning, remove the fenders from the boat if possible. Lay them out on a dock, pontoon, or flat surface where you can work comfortably. Remove any fender covers if fitted - these should be washed separately according to the fabric care label, often machine washable on a cool setting.
Begin the cleaning process by rinsing the fenders thoroughly with fresh water. This helps remove salt and loose dirt, and also softens any dried-on residue. If you’ve recently come in from sea or a particularly muddy berth, this step alone can dramatically improve the fender’s appearance. Use a hosepipe with a spray nozzle or, if you're afloat, a bucket and sponge.
Next, wash the fender using a mild marine-safe boat soap or detergent mixed with warm water. Apply the soapy solution generously with a sponge, soft-bristled brush, or microfiber cloth, scrubbing in circular motions. Pay particular attention to heavily marked areas, but avoid using brushes that are too stiff, as they can scratch the plastic surface. Let the soap sit on stubborn spots for a few minutes to break down grime more effectively. Rinse thoroughly with clean water once you're satisfied with the surface cleaning.
For tough black scuff marks, often caused by contact with other hulls or marina surfaces, a more targeted approach is necessary. Specialist fender cleaners such as Starbrite Fender Cleaner and Vistal Natural Multi Surface Cleaner work well for deep-set marks. Alternatively, household options like white vinegar, isopropyl alcohol, or diluted all-purpose cleaner can be used cautiously. Apply the cleaner to a cloth or sponge (not directly to the fender), then rub gently until the mark lifts. Avoid prolonged exposure to strong solvents, as they can degrade the fender’s surface and finish over time.
Another effective method for removing persistent marks is to use a magic eraser sponge. These melamine foam pads can lift scuffs and stains without the need for harsh chemicals. Used wet, they work through very fine abrasion, so care should be taken not to overuse them or apply too much pressure, particularly on fenders with printed logos or thin outer coatings.
If your fenders have developed a greasy film or oily residue, which is common in commercial harbours or marinas with high fuel use, consider using a degreaser designed for marine plastics. Apply according to the manufacturer’s instructions, then rinse thoroughly and allow the fenders to dry completely.
Once clean, you can go a step further and restore the fender’s shine and protection by applying a UV-resistant plastic polish or protector. Marine-grade vinyl or rubber protectants not only bring back a clean, glossy finish but also help repel dirt, reduce future staining, and extend the lifespan of the plastic. These products are applied with a soft cloth and should be buffed in after application to ensure even coverage.
For long-term maintenance, consider fitting fender socks once they’re clean. These fabric sleeves help prevent dirt accumulation, scuffing, and UV damage while also offering a smart, uniform look. They’re especially useful if you have coloured hulls, which are more likely to show marks caused by bare fenders rubbing against the topsides.
In terms of how often to clean your fenders, it depends on how frequently you use your boat and the conditions in which you berth. For regular marina users or those in tidal or industrial waters, a monthly washdown may be needed. For occasional users in cleaner, freshwater environments, less frequent cleaning might suffice. However, giving your fenders a thorough clean at the start and end of the boating season is a minimum best practice.
Cleaning your boat fenders isn’t just about aesthetics - it’s part of responsible boat care. Dirty fenders can mark your hull, leave residues on fender covers, and give the impression of poor maintenance. Taking the time to clean them properly helps protect your boat, enhances its appearance, and extends the life of the equipment. With just a little effort and regular attention, your fenders will look as smart and capable as the rest of your vessel.
