Bottom Paint - Don't Do This!!!

[markpj23]

I almost put this in the "Worst things a previous owner did" thread, but figured this would be worth a new thread.

The picture shows a checkerboard pattern of growth on the hull. This is after only 11 months since the last hull scrub/wash during my purchase survey.

Anyone want to guess what caused this???

[Island Mike]

It almost looks like the pattern made by an incomplete spray wash from the yard?

[mike d.]

i reserve the right to change my mind? i would concur with island mike but the pattern lokks like a lousy paint job. i am guessing you have the yard do the wash in the fall and prep and paint in the spring. looks to me as if they only painted below waterline. where is the boatkept in water. with all the rain this yr. am wondering if the run-off brought a lot of nutrients into the water and created a plentiful food soarce for growth?
enlighten us as to what happened !

[Boracay]

My guess is that it rained just after the paint was applied and that the boat was put back in the water some time after this.
Where the paint got wet is has somehow become "activated" but where it has dried out it has not worked nearly as well.
My understanding is that with some bottom paints the boat has to go back in the water before the paint fully dries.

[S/V Elusive]

They didn't move the damn supports and paint those spots! Geeeesh.

[ssullivan]

Looks like you had a pretty uniform growth, then something ran down the sides and killed off some of it... or they knocked it off with the slings of the Travelift? Doesn't look like a botched bottom paint job... it looks like something dripped down the hull in the areas where there is no algae growth.

Although, looking at that other prop picture, nothing would have dripped down there. I think it might just be what growth will look like as it *starts* to grow. I've never seen a boat hauled out that early in its bottom paint life. Still, it seems like some acid rain or something might have been going down the sides of the hull and making those streaks where you see no growth. If you can bottle it...

[senormechanico]

I know wing keels add lift, but I suspect an interference pattern was generated in the water when you sailed too fast. Seven stripes are visible, meaning you went 1/7th the speed of sound thru the water. SLOW DOWN and smell the seaweed!


<sarcasm>

[fstbttms]

Here's my shot in the dark; the previous owner didn't mix up the paint before applying it so the biocide went on sporadically leaving large areas of what is essentially house paint on the hull.

[markpj23]

Wow - I've managed to stump the panel!!

This picture was taken before the power-wash, so this was as-found after 11.5 months in the water.

Although I like the "sailed too fast" theory, what actually caused this was being stingy to the point of foolishness. When you use a "dry roller" - meaning when you try to stretch your bottom paint coverage, this is what can happen.

Close inspection of the growth areas show lots of fibers from the paint roller. This provides much more surface area for the grass & critters to attach to, plus the paint is quite thin in those areas. Another gallon of paint and a smarter person driving the roller would have avoided this.

Moral of the story: Don't be foolishly stingy with the bottom paint! Make sure the rollers you use are in good condition - and that you haven't left them uncovered during your lunch break!!

Although I guess we gained at least 1/1000th of a knot due to less weight on the hull... problem is that advantage disappears after 1 hour in the water due to the growth formation.....

[ssullivan]

Very interesting. Guess I never saw anyone try and stretch bottom paint. Seems like a bad idea since hauling to paint costs much more than the extra gallon. This does indeed qualify for the other thread! Bad PO!