Best way to remove harbor scum and moss from waterline and transom?

[magentawave]

My sailboat has a lot of scum and moss built up along the waterline and on the sugar scoop transom. I tried to remove it with the rough scrubbing side of those green scouring pad but that was useless. If you look closely at the photo of the gunk on the waterline you will see that there's a blue boot stripe underneath of it.

Got any ideas for the best way to remove that gunk without hauling my boat and without destroying the LP paint?

Thanks!


Sorry my big finger is in the way but you can still see the transom!

 

[FunInDuhSun]

A pressure washer should get most of it. I had a similar problem and raised the bottom paint to 2” above the loaded waterline, with the bootstripe above.

 

[KJM]

I had a very similar mess on mine after a summer in the water. Pressure washer only reduced it by about 1/2 but wouldn't take it completely off. I sanded it off today only because I plan to re=gelcoat my boat. If you find a good removal method I'd like to know it!

 

[Scott Danforth]

bleach and a scrub brush

 

[magentawave]

A pressure washer should get most of it. I had a similar problem and raised the bottom paint to 2” above the loaded waterline, with the bootstripe above.

Are there pressure washers that can work with my boat in the water?

 

[magentawave]

bleach and a scrub brush

Do you spray the bleach on with a spray bottle? Do you use a super stiff bristle brush?

 

[Emerger]

Are there pressure washers that can work with my boat in the water?

Any pressure washer will work. Of course a gas powered one, not electric. You can actually blast algae off your hull underwater with one if you hold it close enough to the hull. If your problem is right at the waterline it will work fine. Be prepared to get wet doing it.

 

[magentawave]

Any pressure washer will work. Of course a gas powered one, not electric. You can actually blast algae off your hull underwater with one if you hold it close enough to the hull. If your problem is right at the waterline it will work fine. Be prepared to get wet doing it.

I have never used a pressure washer before. Is there a PSI and a specific nozzle tip I should use that won't tear the paint off?

 

[Emerger]

I have never used a pressure washer before. Is there a PSI and a specific nozzle tip I should use that won't tear the paint off?

Any pressure washer will work. They are usually 2500-3000 psi. Usually the yellow nozzle is a fan type pattern. Hold it away from the hull as you are spraying then move it closer until it begins to remove the algae. A pressure washer normally will not remove paint. It's something you have to get a feel for. It only takes a couple of minutes to get the hang of it.

 

[FunInDuhSun]

What Emerger said....

 

[magentawave]

I was asking about the PSI because my son has a beast of a pressure washer that will do up to 4200 PSI. Sure seems like even 2500 to 3000 could do some serious damage to the paint. I was at a self-serve car wash recently and accidentally got my hand in front of the spray nozzle for a second and the stream cut my hand. But like you said, I guess the key is to start kind of far away and move in until it starts removing the green stuff.

My boat is way out on a mooring so I wonder if I can find a pressure washer that will suck up sea water?