How To Easily Remove
Stains From Boat Hull

Paul Luisi
by Paul

Removing stains from the boat hull will improve the overall aesthetics of the vessel.

There can be a build up of waterline stains, brown stains, oxidation stains, yellow stains and tannin stains, especially on fiberglass boat hulls with a gelcoat finish.

What's the best way to remove these stains from the boat hull?

To remove stains from the boat hull: 

  1. Place the boat on a trailer or lift
  2. Use a pressure washer to remove excess dirt & salt water
  3. Scrub the boat hull with a brush, warm water and hull stain remover cleaner
  4. Rinse the stain removal cleaner from the hull with the pressure washer
  5. Dry the hull with towels to remove final stubborn stains
  6. Apply a boat polish to the hull to add a shine

Applying these steps will remove even the toughest of stains from the hull.

Step 1: Place The Boat On A Lift Or Trailer

To remove stains from a boat hull, the vessel will need to be taken out of the sea water.

Taking the boat out of the water first will:

  • Make it easier to remove stains: The boat taken out of the water makes it easier to remove hard stains and polish it.
  • Ensure a thorough clean and no missed stains: With the boat out of the water, you can clean stains from spots not reachable when the vessel is in the water.
  • Help remove stains faster: With the boat out of the water, you can apply cleaning agents which will dissolve stains much faster than manually trying to scrub them out when the boat is in the water.
Take the boat out of the sea water. This will make it much easier to remove all stains from the hull and apply the boat polish.

Step 2: Use A Pressure Washer To Remove Excess Dirt

Use a pressure washer to remove the excess dirt and easier stains from the hull. This will: 

  • Remove the loose dirt and stains from the hull first: A pressure washer will blast away the easier loose dirt first before tackling the deeper stains.
  • Remove salt deposits from hull: The pressure washer will remove the salt deposits on the hull.
  • Prepare the hull for stain remover cleaning product and boat polish: Using a pressure washer will blast away all salt deposits and heavy dirt. This will make the marine hull stain remover and boat polish more effective when applied to the hull.
Use a pressure washer to remove loose dirt and stains from the hull. A pressure washer will also remove salt deposits caused by the sea water and prepare the hull for applying stain removal hull cleaner and boat polish.

Step 3: Scrub The Hull With A Brush And Hull Stain Removal Cleaner

Scrub the hull with a soft bristle brush, warm water and hull stain remover cleaning product.

Using a hull stain removal cleaner will:

  • Remove all stains from the hull: A specially formulated stain removal cleaning product will help remove those yellow, brown, water and scum line stains from the hull.
  • Restore original color: A stain removal cleaner will help restore the hull back to the original color when it was new.
  • Add a protective coating: Using a stain removal hull cleaner will help add a protective coating to the hull to reduce new stains from forming.
Use a brush, warm water and hull stain removal cleaner to scrub the deep stains in the hull area.

Step 4: Rinse The Hull With Pressure Washer

Use the pressure washer again to rinse the hull. Rinsing the hull with a pressure washer will: 

  • Remove the dirty soap and stains: Rinsing the boat hull will help remove dirt and stains.
  • Help spot any missed stains: Rinsing the hull will help you spot any tough stains missed during scrubbing.
Rinse the hull with a pressure washer. This will remove all the dirt and stains that was removed during scrubbing.

Step 5: Dry Boat Hull With Towels

Use old towels to dry off the hull once it's been cleaned. Drying the hull will:

  • Remove the final stubborn stains: Using a towel to dry off the hull will remove the final stubborn stains on the hull area.
  • Prepare the hull for polishing: A towel will clear all the final dirt, dust and stains. This will help prepare it for polishing.
  • Remove newly formed water stains: Water stains from cleaning will be prevented if a towel is used to dry the hull.
Use some old towels to dry off the hull after it's been rinsed. This will help remove any final stubborn stains from the hull.

Step 6: Apply A Boat Polish To The Hull

Apply a polish to the boat hull after it's been dried. Applying boat polish will: 

  • Add shine to the hull: Polish will have the hull looking new.
  • Improve boat aesthetics: Boat polish will improve the overall aesthetics.
  • Add extra layer of protective coating: Some boat polishes will add an extra layer of protection to the hull against discoloration and staining.
Polishing the boat hull will add a shine and have the boat looking like new. Some boat polishes will also add an extra layer of protection against discoloration and stains.

Products Needed To Remove Stains From A Boat Hull

The products needed to remove stains from a boat hull are: 

  • A Pressure Washer: This is needed to blast away the toughest stains.
  • Stain Removal Hull Cleaner: This cleaning agent is needed to remove all those stains from the hull without damaging the material.
  • A Bristle Cleaning Brush: This is used to scrub the hull
  • Towels: This is used for drying the hull.
  • Boat Polish: This is used to give an added shine and have the hull looking new.
  • A Bucket: Use a bucket for the scrubbing og the hull with a brush.

The best boat hull cleaners for removing stains are Star Brite Instant Hull Cleaner and Better Boat Instant Hull Cleaner.

A pressure washer, boat hull cleaner, towels, boat polish and a cleaning brush are needed to remove stains from the hull.

Alternative Hull Stain Removal Option

An alternative option for having stains removed from a boat hull is to hire a professional boat cleaning company.

Hiring a professional boat cleaning service will:

  • Ensure all stains are removed: A professional service will have experience removing stains from all types of hulls.
  • Ensure the right cleaners are used: Most professional cleaning companies will have all the required cleaning products needed to remove all dirt and stains from a boat hull.
  • Remove the stains faster: Most cleaning companies will remove stains and dirt from the hull faster than a first time diy project.  
An alternative option is to hire a professional cleaning company to remove stains from the boat hull. Typically, your local marina will provide contact details for these services.


Removing stains from the hull can be achieved in 6 easy steps.

The right stain remover cleaner can make a big difference to the overall aesthetics of a boat hull.

These stain removal steps can be applied to different types of hull material from fiberglass to aluminum hulls.