Best Boat Hull Cleaner | Toilet Bowl Cleaner?

remove boat rust stains with toilet bowl cleaner - Best Boat Hull Cleaner

In this article, we will discuss popular boat hull cleaning products that I have personally used to get my boat’s hull clean and looking like new.

Cleaning your boat’s hull is a necessary chore that no captain enjoys. If you find yourself needing to clean the hull of your boat, you may be looking around the house for common household cleaners you can use to clean the hull of your boat. And then you stumble upon your spray bottle of toilet cleaner. Could this be the best boat hull cleaner? Let’s find out.

Can you clean a boat hull with a toilet bowl cleaner?

Yes, a toilet bowl cleaner will remove scum and dark stains from the hull of a boat. Toilet bowl cleaner contains muriatic acid. This is the reason toilet bowl cleaner is so effective at removing stains from the hull of a boat.

Hydrochloric acid (also known as muriatic acid) in toilet bowl cleaner is the main ingredient in most toilet cleaners and is a potent chemical you should always use care when using it to clean any surface, including the hull of your boat.

Additionally, if you read the product’s label, it mentions it is advised you only use chemical products for their intended purpose.

With this said, toilet bowl cleaner works wonders to get scum and algae off the bottom of your boat hull, but it was not designed or marketed for that purpose, so take this into consideration.

Improper use may harm the hull of your boat or cause discoloration. This raises the question, what products are designed to take scum and algae off a boat hull.

What Is The Best Boat Hull Cleaner?

Star-Brite Eazy Off Bottom Cleaner

Best Boat Hull Cleaner | Toilet Bowl Cleaner? 1

Star-Brite Eazy Off Bottom boat cleaner is an acid based cleaner specifically designed for cleaning the hull of a boat.

It is an effective cleaner for boat hulls. Because it is designed for the use on boats you know it is safe for cleaning fiberglass boat hulls.

On Amazon, this product got 4.5 stars with over 200 customer reviews. I think that speaks volumes to the quality of the Star-Brite Eazy Off Bottom Cleaner.

The marketing material states EZ-ON/EZ-Off Hull and Bottom Cleaner cleans boat bottoms, removes marine deposits and light stains, whisks away scum lines quickly and easily.

It is excellent for removing marine deposits from rubber inflatables. Star-Brite Eazy Off Bottom Cleaner is safe for use on fiberglass, wood, iron and painted surfaces. Notice the packaging did not say aluminum!

I purchased my Star-Brite Eazy Off Bottom Cleaner at a local boat shop, but you can also get it at Amazon. [Buy on Amazon]

Zing Boat Hull Cleaner

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Zing Boat Hull Cleaner is designed to remove algae stains, grease and grime from your boat’s hull.

Zing 10007 is a professional boat hull cleaner with a four-star rating on Amazon but far fewer reviews than the Star-Brite cleaner. It is safe on fiberglass and painted wood.

The Zing Boat Hull Cleaner does not contain any phosphates as part of its ingredients. [Buy on Amazon]

The Works Toilet Bowl Cleaner

While toilet bowl cleaner is designed for toilets and not boat hulls, I have had great results with the dollar store toilet bowl cleaner. That’s right, one bottle costs $1, the brand I purchase is called “The Works” and one bottle will do the bottom of my 25-foot boat.

If you do not have a Dollar Tree in your town, or if convenience is more important than price, you can buy it from Amazon but it will cost you more. Here’s a link so you can at least see what I am talking about. [Buy on Amazon]

Now you know a few of the options for products to use to clean stains off the hull of your boat, but this leads to the question of HOW to clean the hull of your boat with an acid based cleaner like toilet bowl cleaner or EZ Off?

How To Clean Boat Hull With Toilet Bowl Cleaner

It is important that you do not skip any steps when you’re putting toilet bowl cleaner on a boat.

If your boat really isn’t that dirty, maybe just a good all-purpose degreaser like simple green will do the trick. However, if you are reading this article, chances are your boat hull is beyond just basic cleaning.

To help return your boat hull to a clean crisp color without stains and algae, we need to bring in the strong chemicals to make the job easier. Here is what you need to do…

Step 1:

Rinse The Boat. This can be done with a garden hose or preferably a power washer, and you have to do it on land. I do not recommend using harsh chemicals in the water.

Step 2:

Wash The Boat With Soap. Pick your favorite automotive or marine soap and give the boat a good bath.

You might elect to use dish soap and sponge but it will strip all waxes off of your boat, so you might want to stick to the milder soaps if you do not plan to wax the entire boat.

Step 3:

Rinse The Soap Off. This one is pretty easy to understand. You want a clean surface to begin the toilet bowl hull cleaning process. You might be tempted to jump over the prior steps, but please don’t.

You see, pre-washing your boat gets off a lot of dirt and debris that could cause scratches and scars to your fiberglass gel coat.

To have that mirror finish, you need a smooth gel coat. For this reason, it is important to follow all the instructions I have outlined.

Step 4:

Apply the Toilet Bowl Cleaner. I prefer to let the boat dry a little bit, but you can do it when the boat is still wet if time is a concern. Wearing protective gear like rubber gloves and goggles, you can spray or brush on the toilet bowl cleaner.

Know that if you use a soft bristle brush, the acid can damage the glue holding in the bristles and ruin your boat deck brush… I learned this the hard way!

Because of this, I prefer to buy a long-handled tire scrubbing brush from the Dollar Tree (yes, for $1) when I am picking up the toilet bowl cleaner.

Then I pour the full bottle of toilet bowl cleaner into a five-gallon bucket. I use the long-handled brush to apply the toilet bowl cleaner to the boat hull. Be sure to pay extra attention to the waterline!

If you are concerned about your boat, try applying it to a small area first to ensure there is no corrosion.

After direct application, let the toilet bowl cleaner sit for a minute or two. You will see it working.

Use your own judgment for how long you want it to sit on your hull. Typically I limit it to 2 minutes. I prefer not to let the toilet bowl cleaner fully dry on the boat hull, but I prefer to let my eyes be the judge.

*Note: You can always apply a second application if needed.

Step 5:

Rinse, Rinse, Rinse! You have to flush the acidic toilet bowl cleaner off of your fiberglass boat hull.

Step 6:

Wash the hull again with soap and water. Most boat soaps have a balanced pH balance, and this will assist in neutralizing the muriatic acid in the toilet bowl cleaner.

Be sure to rinse and dry your boat to prevent water spots, especially if you rinse it with hard water.

Step 7:

Wax the boat hull. You will be tempted to skip this step but your efforts will be wasted and your boat will look even worse the next time you leave your boat in the water if you don’t do this step.

If you are unwilling to put protective white gel coat wax or sealant on your boat hull, do not bother cleaning it with toilet bowl cleaner or any other hull cleaners.

Cleaning your boat hull this way strips away everything from the hull. When you put your hull into the water unprotected, it will get even more growth and will probably look worse than before!

For this reason, you simply must protect your boat hull with a high-quality wax or sealant after cleaning the boat hull with toilet bowl cleaner or other acid based cleaners.

Here Are Two Waxes That I Highly Recommend:

Best Paste Wax For Boats:

Best Boat Hull Cleaner | Toilet Bowl Cleaner? 3

Collinite Fleetwax 885. Use the paste, not the liquid. I have had excellent results, and it lasts a long time. [Buy on Amazon]

Best Liquid Wax For Boats:

Best Boat Hull Cleaner | Toilet Bowl Cleaner? 4

Nu Finish. This is a liquid wax and it is marketed as a once-a-year car polish. It works great, lasts a long time and it is cheap. I like cheap! Not to mention it got a 4.5-star rating with other 1,000 customer reviews on Amazon. That is hard to accomplish. [Buy on Amazon]

*Update: I cannot verify if they changed their formula, but I just bought a new bottle and I do not think it lasts as long.

Bonus Recommendation:

Best Boat Hull Cleaner | Toilet Bowl Cleaner? 5

McKee’s 37 Hydro Blue Sio2 Coating. This is personally one of my favorite products on the market. I use it for everything, and I buy it by the gallon. I am not kidding. It is so easy to use.

It only lasts for 3-4 months but makes protecting your boat, car, plane, RV, etc., so much easier. Just go ahead and put it in your cart, and you can thank me later! Just be sure to shake it up really well before you use it. [Buy on Amazon]

Is toilet bowl cleaner okay to use for cleaning scum off the hull of my boat?

In general, yes, using toilet bowl cleaner is okay to remove scum, algae, barnacle growth, and other stubborn rust stains off your boat’s hull. You need to be careful when using toilet bowl cleaner because it contains strong acid chemicals.

Does toilet bowl cleaner shine aluminum?

I’ve only used it on fiberglass hulls so I cannot speak specifically to its effectiveness of cleaning or shining aluminum. I did a quick search on the internet and one forum mentioned that sulfuric acid will eat away aluminum. For this reason, I would probably keep the acid away from your aluminum, or at the least, I suggest doing more extensive research. For this article, I am focused on cleaning fiberglass hulls.

Will the muriatic acid in toilet bowl cleaner kill my grass?

Yes, if you clean the hull of your boat with toilet bowl cleaner it can kill your grass since it has acid as its active ingredient. Your grass might survive if the acid is heavily diluted by water from washing your boat, but I would proceed under the assumption the grass would be killed.

Will Toilet Bowl Cleaner or other Acid Based Cleaners Strip The Wax from the Hull of My Boat?

From my experience, yes, toilet bowl cleaner will strip away the protective wax applied to a hull. If you are getting algae growth or staining on your hull, the protective wax has probably already broken down and will need to be reapplied. For this reason, a good deep cleaning with toilet bowl cleaner before applying fresh wax or sealant could really bring out the shine on a dirty boat hull.