How To Clean a Boat Hull In The Water (Environmental Friendly)

Struggling with maintaining the hull of your boat?

Or want to keep it clean without taking the boat out of the water? Well, this article will cover exactly how to clean a boats hull in the water and how to get rid of those annoying water stains or water lines too.

Let's face it, nobody likes a dirty boat bottom, do they? 

Neglect to clean the bottom of your boat and you'll most likely end up with an ecosystem or marine pests living under there. If you're new to hull cleaning activities, it's important to adopt a regular cleaning program of boat maintenance & cleaning the hull should be part of that.

As a word of caution, some of the suggestions I'll give will involve you getting in under your boat. Make sure you have someone with you while doing this in case something goes wrong. Underwater hull cleaners can can sometimes have a dangerous job especially if your boat is moored in a busy marina.

Okay, safety disclaimer complete! Let's dig in.

Here's what we will cover

  • Best Ways To Clean A Boat Hull
  • Environmental Protection Hull Cleaning
  • Ship Hull Cleaning
  • Boat Bottom Cleaning Tools
  • Marine Citrus Cleaner
  • Boat Hull Scraper Method [Video]
  • Hull Rotary Brush Method [Video]
  • C Pole Hull Cleaning Method [Video]
  • Hull Rotary Machine Method [Video]
  • Pressure/Gravitational Washer Method [Video]
  • Cleaning Pads/Gloves
  • Hiring cleaning divers
  • Boat wash service
  • Cleaning A Fiberglass Boat Hull (Things To Be Aware Of)
  • Price Comparison (DIY v hiring boat cleaners)
  • Hull Cleaning Service

It's important you are brushed up on the current marina regulations as different marinas apply different rules to vessel owners.

The vessel size will dictate which method you choose to eliminate those marine pests and general marine growth so let's have a look at those methods.

Best Way To Clean A Boat Hull In The Water

cleaning a boat hull in the water

Take a look at that image, you obviously don't want your hull to get in that much of a state?

So what are some great ways to clean the hull in the water without it getting to that state?

Luckily, there are some very easy ways to maintain the cleanliness of the hull without spending a fortune on cleaning supplies or hiring people. Cleaning boats doesn't have to be boring and you don't always have to hire expensive hull cleaning divers.

Now, here's something you should know if you haven't been keeping your hull in good shape.

A build up of dirt, an eco system, barnacles, sea weed and everything you can imagine in sea water can have some pretty negative effects on your boat.

Here are some of those effects you might not have considered:

  • Slow the boat
  • Overheat the engine
  • Effect/Damage your navigation equipment

These are just some, so it is very important to keep the cleaning of the hull in check. The last thing you want is an overheating engine.

I'll list out all the different ways you can clean your boats hull while the boat is in the water and you can simply pick your favorite.

Some methods are better than others (by better I mean get the job done properly) while other methods are for only cosmetic cleaning of the hull so keep this in mind.

Underwater Hull Cleaners Tools

There are many different cleaning tools available to tackle cleaning the hull. If you're like me, you hate the thoughts of having to do this but obviously it's something that needs to be done.

There are a few options to use for cleaning tools. We'll discuss both DIY options and people you can hire so there is something for everyone.

Below are some of the cleaning tools we'll discuss & how to apply these tools while the boat is in the water:

  • Boat Hull Scraper
  • Rotary Brushes
  • Pressure Washers
  • Microfiber Towels
  • Boat Bottom Cleaning Pads/Gloves

Luckily, these options are cheap and will save you time. However, some are simply better than others are getting the job done.

Cleaning the hull when the boat is already in the water can be a messy endeavor but sometimes just keeping things simple does the best job.


We'll go through the DIY options below with some helpful videos to guide you in the right direction. There's no need to break the bank with your cleaning too so don't worry, these options are inexpensive.

We'll break up these cleaning options into different methods.


If you don't mind getting dirty and physical with the cleaning of the hull, you can use a scraper. Now, something to keep in mind with a scraper is you can scratch the paint.

If this isn't an issue, you can always just scrape any build up off. This is particularly useful for a build up of barnacles as they can be tricky to remove.

bottom cleaner
Image credit: top shelf marine

A simple boat hull scraper is all you need to get started. You can check the latest prices on Amazon and grab one.

With this, you'll need some snorkeling gear to get in under the boat. Here's a video of someone cleaning their hull with a scraper.

This hands on approach can really get the job done. Again, this is especially useful for a build up of barnacles.

You'll need some swimming gear, (everything you'd wear snorkeling) & the scraper. You're good to go once you have those items.

Pro tip: Make sure the weather is nice. (seems obvious but I've seen people attempt to clean a boat hull in storms.)

boat hull scraper

image courtesy of usedvictoria

Not a bad prop clean is it?

The best thing about this method is how easy it is to do. They aren't heavy to lift (weigh less than a pound) and can be very effective.

So method one of cleaning your hull gets a thumbs up from me.

hull cleaning


This is a different type of boat hull scraper. The best part is you can do it from the ground while the boat is in the water.

Confused? Just look at the image & video below to see this in action.

cleaning the hull of a boat
Image credit: powerboat-world

This can be great for getting the bulky stuff off the hull of the boat without ever having to get into the water.

However, it's worth keeping in mind that it will not remove all dirt etc. but will help keep things like barnacles at bay.

The problem is it takes a lot of force to try clean the hull this way. Don't believe me? Simply try this method yourself and watch how tough it is to do.

Here's a video of a scrub head version of this in action:

Think this would be a useful addition to your boat cleaning tools, you can get it on Amazon.


Similar to the Scrubbis cleaner above, the c pole can help you clean the hull of your boat from your own boat deck.

Shaped like the letter C, this cleaning pole can curve right in under the hull to help scrub off dirt.

c pole cleaner

This can actually be quite effective and is definitely something to consider if you want to clean your boat's hull without stepping foot in water.

The material also means it won't scratch your paint. But it' still only best for cleaning dirt. Getting other things like barnacles will be tough with just this as they require some force to remove.

Here's a video of the C pole in use:

The c pole is another alternative and really helps with cleaning smaller boats.

Obviously, you wouldn't use this on a large boat but for those with smaller boats, this can really be a great addition and best of all, it doesn't require you getting into the water.

The C Pole retails at approx. $355 and you can find one with a quick google search. This will be an option for some of the readers but not all.


For people willing to cleaning the hull themselves and not mind getting into the water, this is a great option. The rotary brush method helps remove all kinds of dirt etc.

This is a proper machine that really will dig into the tough areas. I was concerned that the brush system would wear out fast with removing barnacles but it's stood the test of time.

If your boat is big, you'll also need a scuba tank to breathe!

This is an expensive option but if you're hands on and don't mind spending to get the job done properly, this is an option for you.

bottom cleaner

This option is best for people who clean the hull regularly. Powered with a 21AH Battery pack, you can clean as far as 22 feet dept (recommended) and 36 feet maximum,

Here's a video of this tool in use. Skip to 56 seconds to see this in action (it's quite satisfying) :

For the DIY options, this is by far my favorite option. However, this does come with a steep price tag so it's not for everyone.

It retails at $1,700. (this provides the full kit) You can find cheaper alternative rotary brushes but this is my favorite.

Now, if you are going down the route of hiring divers to clean the hull (we'll discuss this option below), this might be a better option as the cost of hiring divers can add up over time.

Another thing to keep in mind is the kit comes with everything you need, charger, brush heads etc. so there are no nasty surprises when you buy one. (which isn't the case with some other similar options on the market)

It's also a great bottom cleaner kit to tackle those tough and stubborn areas.

What is the best way to clean the hull of your vessel to protect the environment?

There are some environmentally friendly products and ways you can clean your boat hull without harming the marine ecosystem.

Marine Citris Cleaner

marine citrus cleaner
Image credit: 303 products

Another great product is the marine citrus cleaner & degreaser. You'll most likely find it in your local marina store or online at Amazon. It is approved for use and is not a pollutant for the marine environment. Pollution prevention is important after all.

It's also relatively cheap and it can help protect boat paint too!


The gravitational cleaning washer option is more of a professional solution similar to the rotary brushes. This helps blast away dirt, barnacles, fouling etc.

This option is not necessary for the majority of readers but still something to add to your available options for cleaning a boat hull.

Instead of trying to explain how it works in writing, here's a video showing exactly how it operates.

Obviously, it looks great on paper but for a casual boat owner, this is above and beyond what is necessary to clean a hull.

It's also very expensive with prices above $4000 for a system. (not to mention the fuel costs)

Also, I can see the loud generator making people in the marina angry so keep that in mind too.


Pretty straightforward to use is the microfiber towels. This is best used with cosmetic dirt but is tricky with barnacles, foulings etc.

This is a great option also for reducing the potential for paint damage and is very popular with fiberglass boats.


boat bottom cleaning pads

This is one of the cheapest DIY boat hull cleaning option. You can simply buy some cleaning pads and use some snorkeling gear and start cleaning.

Here's what some of these pads look like. You can get them shaped like gloves so there is little to no weight using them in the water.

Honestly, for the majority looking to keep the cosmetic dirt off the hull, this is the best option. You can grab a pair for $8 -$20 online.

I'd get a couple of pairs of these to be safe as these tend to wear quite quickly with frequent use. Again, as a reminder, this is best used when cleaning simple dirt off the hull.

These cleaning pads will not work well with things like barnacles or sea weed build up.


diver to clean boat hull

image courtesy of wamarine

Now, as we are discussing options for cleaning the hull of your boat while it's in the water, this is yet another option available.

If you cannot stand cleaning your boat or just want a proper, thorough job done on it, you can always hire divers to do it for you.

The best thing is there are companies out there who's job it is to clean hulls of boats/ships/yachts etc.

Now obviously this isn't for everyone but if you want to hire a professional, it's something to consider.

And this option isn't reserved for the larger boat owners. There are services available for the smaller boat owners too.

How much does boat hull cleaning cost? On average, it costs between $10 - $50 per foot. Prices will vary from size of boat, hull condition etc. but this is the average price range.

Where can you find these services?

Well, as simple google search will suffice. Another tip is to contact your local diving center as they may be able to put you in contact with someone providing this service.

Obviously, you don't want an amateur on the job so make sure the person you hire has some experience if it's an individual rather than a company you hire to clean the hull.

You can read our top 6 best boat hull cleaners to have the hull looking clean and new.


When you're cleaning a fiberglass boat, be careful using things like the boat scraper above. You don't want to take chunks of paint off the hull but it will happen (normal wear and tear)

Here are some things to avoid (or use sparingly):

  • Hard brushes
  • Steel wool
  • Aggressive use of boat scraper

Obviously with a fiberglass boat, you should use the above with care. You don't want to cause some serious damage to your hull and open up a whole load of new problems.

So when cleaning a fiberglass hull, use microfibre towels, a simple cloth, cleaning pads or something similar to the rotary brushes mentioned above. These cleaning products will help with removing stains from the boat hull as well as dirt build up.


So there are a lot of different methods to choose from when cleaning a boat hull in the water. Let's summarize the available options.

We'll divide them up into DIY and service options.


clean boat hull costs

Marina Rules

It's important to note that there are different rules in marinas for what a vessel owner can and cannot do. Before entering marine waters to clean the vessel bottom, you will need to know these rules as well as well as a clean boating guide that most marinas will provide.

Don't forget, when using any chemical bottom cleaner to keep the clean water act in mind.

Incase you don't know what that is : The Clean Water Act is a U.S. federal law that regulates the discharge of pollutants into the nation's surface waters.

Cleaning Facilities

One final thing worth mentioning which can save you some money on buying cleaning products is to have a look a the cleaning facilities of your local marina.

Marinas will have special discounts in place so there is no harm in asking plus if you are going down the route of hiring a hull cleaning service or hull cleaning divers, they will most likely know the best ones in your area.


Cleaning the hull of your boat in the water doesn't have to be a difficult task. As mentioned above, there are many different options available to get the job done.

You can use simple and cheap options like the cleaning pads/gloves or fork out some cash on rotary cleaning systems if you want to do a more professional and thorough job.

The cost of cleaning a boat hull will range based on the size of your boat and the condition of the hull.

As stated, there are benefits and pitfalls with each option but all in all, you can do a very good job cleaning the hull while the boat is still in the water.

Not many people enjoy cleaning, while others absolutely love it. If you enjoy cleaning, grab your snorkeling/diving gear and get ready to remove all that crap under your boat.

Obviously, don't let this build up to much over time. Your engine/navigation equipment will thank you and remember to always have good boat care cleaning timetable as part of good hull maintenance and ensuring much better boat performance

Now go and scrub those hulls and always ensure you have a clean bottom.