Author Topic: Anti fowling paint  (Read 5103 times)

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Todd j

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Anti fowling paint
« on: November 03, 2019, 10:20:12 PM »
I looked over the entire forum and think we need a thread dedicated to anti fowling bottom paint. My wife talked about leaving the boat moored for summers in the salt.  I had planned on a black graphite bottom treatment.   The lists of bottom paints is nearly endless. 
   Let’s start a report listing paint types and performance here!
 

Brian.Dixon

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Re: Anti fowling paint
« Reply #1 on: November 04, 2019, 06:17:44 AM »
I agree ... some real experience would be great.  There are new coatings and products out there too.  I've never kept a boat in a slip for the summer or year around, but I know that if you leave the boat in the salt year around that you use a 'soft' or 'ablative anti-fouling pain', and if you trailer more often than how long the boat stays in a slip, then you use a 'hard' or 'non-ablative anti-fouling paint'.  The hard version needs recoating far less often, and the soft one usually requires annual recoating.  Having kept one boat in slip for one summer, a gel-coated glass boat, and dealing with the growth issues ... I'd say that it's not a big deal.  You hose down the bottom of the boat with a strong ammonia mixture, spray off with a jet of water, repeat.  It comes off without too much work.  Given that, I suspect that the non-ablative 'hard' anti-fouling paint would be a good choice for you and it would at least minimize the pre-winter storage clean-up work that you have to do.  More than this ... I dunno.  It would be nice to hear some real-life experiences on this.

Brian

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kennneee

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Re: Anti fowling paint
« Reply #2 on: November 04, 2019, 08:56:37 AM »
I have had good luck with Pettit Hydrocoat. Very clean bottom after 4 months in the water.
Ken

Todd j

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Re: Anti fowling paint
« Reply #3 on: November 08, 2019, 11:13:32 AM »
My favorite local marine store sells Interlux and Pettit.  The phone guy recommends micron and vivid respectively.   I read reviews and testimonials on both.  There is as many mudmouths on each as there is glorious tales of anti fouling badassery.   Sooo.  I guess I will just nut up and try the one that I have the best chance of success.  Given my level of skill, shop, and temps this time of year.   
   I’m open to suggestions as always!
« Last Edit: November 08, 2019, 11:14:27 AM by Todd j »

Todd j

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Re: Anti fowling paint
« Reply #4 on: November 12, 2019, 07:43:01 PM »
Yesterday I covered the boat with graphite epoxy.  I used the level line as described in the plans.  I went 8” down from the chines at the transom.  I found out my spray rails are 1/4” different at the aft end.  No surprise I guess.  I looked at lots of boats and there is so many different ways to paint the bottom.  I’m not married to anything yet.  I tried to follow the rails curve and could never get it to look right.  I may try following the chines and mirror the the smile in the rails this weekend, just not sure how to handle the paint at the bow.  It is tough when a person doesn’t have imagination  I’m not sure how I like it as of now.  I’m getting pretty anxious to flip.  Opinions and observations welcome!
« Last Edit: November 12, 2019, 08:18:21 PM by Todd j »

Brian.Dixon

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Re: Anti fowling paint
« Reply #5 on: November 13, 2019, 06:07:06 AM »
I think it looks spectacular!  Great job!

Brian

The Great Alaskan - Professional performance - Easy to build! - https://www.glacierboats.com  ><((((?> ... ><((((?> ... ><((((?> ... ><((((?>

Todd j

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Re: Anti fowling paint
« Reply #6 on: November 13, 2019, 06:43:26 AM »
That’s reassuring.  I may just go with. Easier for me!

json

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Re: Anti fowling paint
« Reply #7 on: November 13, 2019, 07:59:19 AM »
I did the same thing (laser level) and I was thinking my bottom coating looked uneven due to how far below the chine junction at the bow looked, but yours looks about the same, so both of us can't be wrong right? :) I think I will probably go with it, since I have it basically already done. Looks great though, how many coats on the bottom did it take you to get it color saturated like that? I think I am on about my 5th coat, but I am going super thin and needed to fill the weave as well.

Todd j

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Re: Anti fowling paint
« Reply #8 on: November 13, 2019, 10:05:34 AM »
That was 1 coat.  I will cover it with clear epoxy just to be safe.  I did have at least 2 coats of clear epoxy on before that.  I just scooped the graphite in the mix  not measuring.  Just needed some contrast

Djeffrey

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Re: Anti fowling paint
« Reply #9 on: November 13, 2019, 05:36:02 PM »
I followed a little different line but yours looks fantastic

Todd j

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Re: Anti fowling paint
« Reply #10 on: November 13, 2019, 10:14:51 PM »
I like that too.  I don’t know if 1 gallon would get two coats covering that much hull given the paint coverage of my paint?

Todd j

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Re: Anti fowling paint
« Reply #11 on: November 24, 2019, 10:43:42 PM »
I used amercoat 240lt epoxy primer and Pettit Unepoxy bottom paint.  Adhesion was great.  Both products covered well. 2 coats each.  My finish ended up heave eggshell/orange peel.  Not convinced this is the finish I was after.  I used the prescribed roller to put on the epoxy primer.   It just didn’t flatten out at all.  You just cannot flatten it out even with the brush.  Maybe I should have thinned it.  Dunno?   
  I might look into blocking it and recovering just the planing surface of the hull.  Anyone have any thoughts?   I’m concerned I may need to re do it.  The wife will shoot me.  It’s stinky stuff.  Still not aired out!
« Last Edit: November 24, 2019, 10:47:56 PM by Todd j »

Rbob

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Re: Anti fowling paint
« Reply #12 on: November 25, 2019, 07:59:07 AM »
I have read the orange peel makes it glide thru the water better so should be great.
I just looked up that primer, wow 82% solids that is the most I have seen.   I assume you sprayed it so I can only imagine how bad the fumes were. 
« Last Edit: November 25, 2019, 08:04:06 AM by Rbob »

Todd j

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Re: Anti fowling paint
« Reply #13 on: November 25, 2019, 10:36:51 PM »
I used the prescribed roller for the primer. It’s a little hard to tell in the photo, but the bottom is smoother than the sides.  I think this must be attributed to gravity.  Brushing the primer on would haven taken forever and been way too heavy an application in my opinion.
  I did some reading on bottom finishes and I am somewhere in the middle.  Some people that think after several bottom fishes on top of flakey or peeling finishes that think a smooth bottom will somehow gain them many miles per gallon.  With this situation the consensus seemed to be a smooth bottom would never pay back the user with added mpgs.    The other extreme was wet sanding down to 600 grit and other madness that just ain’t gonna happen. 
   I’m torn?  I was hoping to flip this weekend.  I didn’t see on the Pettit data sheet if it could be reapplied after sanding.  I need to look it over again

Brian.Dixon

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Re: Anti fowling paint
« Reply #14 on: November 26, 2019, 07:00:26 AM »
Unless it really bugs you, the textured bottom isn't a big deal.  I've read some articles that seem to conclude that the textured bottom is faster/more efficient and some that seem to conclude the opposite.  They 'say' the textured bottom creates and traps microbubbles along the leading edge where the water meets the forward hull when on plane, and these microbubbles travel along the bottom with less resistance than water does, effectively reducing the wetted surface and parasitic drag.  This does seem to be supported, and it appears corroborated, by the fact that a boat goes faster on a lake with 3-5 inch chop (small) than it does on a mirror smooth lake, and the belief is that the trapped air traveling over the bottom reduces wetted surface.

Others say the laminar flow of water on a smooth bottom creates efficiency.  Who knows?  I conclude that it's not an issue one way or the other, but GO one way or the other.  For example, textured everywhere is good as is smooth everywhere, but if you go for smooth and have rough spots here and there that interrupt the smooth bottom's laminar flow, then that's just more parasitic drag.  One or the other is fine and nothing to worry about.  IN FACT, unless you're racing on a smooth lake, all of this is a moot point .... drive over to the coast on a breezy day and look at the water.  You tell ME what the biggest factors are in terms of speed and efficiency (hint: it ain't how smooth the boat's bottom is).

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