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Just finished bringing SEAHORSE up the coast and back on her trailer at Hillarys boat harbour. She is antifouled but the growth was something else. We motored over half the distance [ about 18 mile] which should have caused most of the growth to slough off, and maybe some did, but there was still a lot left.
When we got home used two large car ramps to support the hull then lowered the trailer bow then stern to expose the sections that sit on the bunks...gave them a double coat of antifouling [ white] before raising the trailer UP to the hull again.
Of course used a HP water blaster for the clean...and a few spots needed a paint scraper tyo remove some persistent barnacles. Did not need to take it down to the bare gelcoat...what antifouling does not come off under that pressure can stay on...and it accepts two fresh coats on top...





I'll try and follow these up with some shots of a CLEAN hull...Puggsy

A couple more pics...Those planks are Western Australian KARRI timber...they will not break...




Puggsy

Dang that looks Nasty! How long was the boat in the water growing that beard?

This was Konig after about 8 weeks in the James River at Norfolk Virginia. Scraped with a plastic paint scraper then cleaned it about 3 days later (after trailering back to Florida) with high pressure water.

I thought I had anti-fouling paint but what I actually have is 4 coats of barrier paint...no anti-fouling. Someday I will probably anti-foul.



Cheers,
Jim

puggsy you said you antifouled with white paint.i have blue antifoul on mine which is verry patchy and worn,if you rub it with your hand it it leaves a stain on them.have tried sanding it off but suspect this would take the rest of the year and still leave blue specks all over hull.do you think its feasable to coat it with white paint just to make it look beter as my boat lives on the trailer.

The antifouling I use is "International" brand "Micron Extra" High Strength Self Polishing Antifouling...as on the tin.
Not cheap...AU$220 for 4 litres. But it did last years job and just got me through this job with only one coat, but managed two on the bunk areas. As you use it it tends to get quite thick and from my previous experience, must be brushed on.. When it is put on with a roller, there is a tendency for air bubbles to be captured underneath it...as it dries quite fast...and these will break and leave the hull exposed for growth.
David...She was in the river for the last 7/8 months...The growth along the waterline was even a bit thicker but I gave her a bit of a scrub...what I could reach with a scrubbing brush...a month ago.
Because this paint is " self cleaning" I might have got her clean on the mooring by swimming underneath, but getting a bit old for that caper.
I plan to be on the trailer for a couple of months, so will leave the second coat till just before she goes back on the mooring.
If the way this stuff sticks to my skin is any indication of how it bonds to the hull, AND I PUT IT ON PRETTY THICK...I'm not too worried about any wear and scuffing in future launchings. The trailer got its share too.
Miss U...dont worry about it coming off as a stain...its designed to slough off...the growth is not given a chance to be permanent...as it would on bare fibreglass..Next time to coat it, bung it on as thick as you like...the thicker the better.
It is not necessary to remove ALL the previous coating. If you are concerned about it, give it a water pressure clean.
Also, being on the trailer all the time, you could use the HARD SURFACE antifouling, designed for power [ faster] boats that live on a mooring...It prevents most of the growth but does not slough off...its mainly for high speed hulls.
A problem with contractors doing the job is that they spray it on...covers it so it looks good but much too thin...On a boat the size of a , 4 litres should get you three good coats...use a fairly stiff, worn even, brush and scrub it on, not leaving a square inch...
If any other queries come up, I'll answer them as best I can...Puggsy

I have the same Micron and just used 80 grit on my orbital sander to smooth out the rough spots and repainted the bare places. The applications guide suggests a 3/8 nap roller which I used. I found the 4" roller worked best with less mess. This left a smooth finish which I later sanded to match the rest of the boat. They suggest 2-3 coats on wearing areas, keel, rudders, bow, etc.

bscott

I leave the hull a bit rough...have you ever looked at a shark skin...not smooth and you can't say they are slow...also it saves a heap of work in the rubbing down... 's not being speed machines do not need the hull of competition boats...

Good grief that's an ugly bottom!!
What do you guys have in the water down under?

How long was that soaking to take on such a mess?

Typical blue boat; that's why I prefer white