How To Clean A Dirty Boat

Written by Paul

Any cleaning products we mention have been used scrubbing our own boats so we know what works. We may receive a commission on purchases made through our links (at no extra cost to you) More details

How To Clean Dirty Boat | Boat Cleaning Products | Safely Disposing Of Dirty Water | Commercial Boat Cleaner Services | How To Clean Dirty Boat Video

Giving your dirty boat a thorough cleaning can be done with some hard scrubbing and simple washing.

To have your vessel looking spotless and new, you'll need general cleaning fluids like boat soap, hot water, stain removal, skid deck cleaner, commercial bilge cleaner and other acid cleaners to tackle that stubborn, hard-to-remove dirt.

Power washing your boat with warm water will also help with the grimiest dirt. But as a word of caution before we get started, when using bleach solutions in a marine environment, it's very important to clean up chemical spills should it occur.

You wouldn't want cleaning fluids spilling into the sea water as if you're caught, you will pay a hefty fine, not to mention the environmental issues.

This boat cleaning guide will apply to most vessels like:

  • Sailboats
  • Pontoon Boats
  • Speed Boats
  • Jet Skis
  • Yachts
  • Small Motorboats
  • Outboard & Inboard motorboats

So there is information that will suit the majority of boat owners here.

Whether it's fish slime, mildew, scum lines or just general loose dirt, we've got a solution to removing it all. However, it does require a bit of elbow grease.

We'll break up the guide into different parts of the boat, from cleaning the boat hull to cleaning the deck & interior.

Cleaning A Dirty Boat, The Products You'll Need

You can get away with boat soap and a simple washing process to remove most of the stains, but the products recommended will make your life much easier and help tackle the grimiest dirt and stubborn stains.

We use these products to have our boats looking like new!


The Swobbit Boat Cleaning Kit helps with scrubbing your entire boat from top to bottom.


Provides a season long protective coating and creates a high gloss finish.


Enviromentally safe boat cleaner used perfectly in conjuction with the cleaning kit to scrub most areas of your boat

You can use the discount code WCD10 at the checkout to save 10%

If you don't want to buy the kit, just use a clean, damp cloth to remove the light dirt. Right, once you have the gear for cleaning your boat, let's get into the steps.

Cleaning The Boat Hull

mild, acid-based stain removers

The boat hull can get very dirty. There can be stubborn stains, water spots and marine life living under there. It's very important to have this area of the boat in spotless condition as it can massively effect performance if the dirt builds up.

The easiest way to clean the hull is when the boat is out of the water. You can use a pressure washer to give it a high-pressure rinse.

This will help remove any of the bulky and heavy dirt build up under there. You can also use the cleaning kit (mentioned above) or another cleaning product of your choice to give the hull a good scrubbing to remove those extra tough dirty areas.

Alternatively, if you cannot wash the boat out of the water, there are options for you too. You can use a simple boat hull scrapper to remove the dirt while it's still in the water.

You can read our cleaning the hull of a boat in the water guide to get more information on how to do this as well as ideal products to use.

If you are doing this in the water, make sure you are using marine grade cleaners and be careful with those acid cleaners or abrasive cleaners as some of them may be problematic for the marine environment.

Cleaning The Boat Deck

power washing boat
credit: aqua-cultured

the boat deck is another one of those important spots on the boat to get clean. You can use a power washer and the cleaning fluids mentioned above to give the deck a thorough cleaning.

The biggest problem on the deck is all the dirty feet that scuff and mark it. You can use a skid deck cleaner to remove dirt.

Alternatively, you can read an in depth article on how to clean a boat deck for a more specific answer.

Some people take cleaning the deck to the extreme and will even paint it with a protective coating to help with erosion from sea water.

This is particularly challenging to do and avoiding common spillages is tough. If you are planning on completely re painting your deck, make sure you allow for a couple of hot weather days to help with the soaking period.

In our experience, any water on the deck paint before it drys will cause the deck to look patchy once it's completely dry so keep this in mind.

Again, painting is on the extreme side and not necessary in most causes but some hardcore boat detailers love to do it.

Cleaning The Boat Seats

vinyl cleaners

The boat interior is important to keep clean as it's where you/your passengers will be spending most of their time while boating.

You can simple use some boat soap or a special boating spray to help wash off mold/mildew etc. You'll also need a clean, damp cloth to help with the cleaning.

Alternatively, you can read our how to clean boat seats guide for specific information on this. Another tip is to use a cleaning soap with a strong scent. A nice smell will keep your passengers happy.

Depending on the size of your boat and the condition of your seats, this generally shouldn't take too long. It's also wise to use a protective spray as seats tend to get damaged in the sun from harmful UV rays.

Cleaning Outboard Boat Engines/Fuel Tanks

Now, cleaning the engine and fuel tanks is not something for the novice. Do NOT disconnect anything if you are unfamiliar with how to reconnect it.

Cleaning the outboard motor can be done with some boat soap, a scrub brush and a bit of elbow grease. This is more than enough to get most dirt off the engine.

If you want to take it one step further, you can read our cleaning a boat fuel tank guide for specifics on this.

Cleaning Boat Bilge

bilge cleaning effectiveness

Who loves the smell from a dirty bilge? 

You guessed it..... nobody.

So make sure you keep this clean as it can bring rotten odors to your boat. You can do this relatively easy. Just turn off the pump and get some cleaning fluids like boat soap or even dishwasher soap.

Use hot water and a sponge and start scrubbing it. You can check out our cleaning a boat bilge guide for more information.

You must dispose of the dirty and oily water appropriately as it's against the law to dump it into the sea.

Adding A Shine To Your Boat

When you've cleaned up your boat, it's always nice to add that added shine. This will have your boat looking brand new. You can use the products (mentioned above) for polishing your boat.

Just make sure if you decide the find your own polish that it is marine grade and environmentally friendly. You can use polish that will also help protect the paint of the boat too.

Disposing Of Waste/Dirt From Your Boat

If you are cleaning your boat in the water, it's particularly important to dispose of dirty water appropriately. Otherwise you may see yourself with a fine.

Make sure to clean up chemical spills, solvent spills and the dirty wet soapy water in the right place. Marinas generally have a specific place for you to do this. (generally where you can pump out the boat) 

This can get messy fast so it's important to do it right.

Commercial Boat Cleaners

Another option for those that don't want to clean their boat themselves is to hire a commercial boat cleaner. This can be a great option if your boat is particularly dirty and hasn't had a good cleaning in quite some time.

You can find these boat cleaning services with a simple Google search with your local area. Alternatively, you can find thee services on Craigslist.

As with everything on craigslist, be careful who you hire and do your due diligence. Another option is to contact your local marina or marine shop and ask them for recommendations in your area. (This is the best option)

The price will vary depending on the size of your boat and the condition of the boat.

How To Clean A Dirty Boat (Video Instructions)

You can also watch the video instructions below by thatboatguy on how to clean your boat.

As you can see, it's relatively easy to do and you'll be done in no time. Obviously it'll depend on the size of the boat but for the average small boat, you should have it looking spotless in under an hour.

When cleaning all the dirt from your boat, you will also need to pump out your boat to remove any unwanted dirt and keep things clean.