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Floatation Foam in Sunfish

tsmart

New Member

Couple Questions;

1) Did '70ish model Sunfish Boats come w/ open cell floatation foam inside the hull?

I done some inside the hull inspection on the rear end of mine.... and there's some foam that looks like a Styrofoam cooler (white, closed cell foam). Seems some ants invaded the white foam, and have eat it up quite a bit.... and nested in it - so I am removing it to add new foam..... But, the white foam was held in place by some "yellow" foam.... which looks like the spray insulation foam (open cell) which you can get at Lowes. The yellow foam, was retaining water - thus I am replacing it as well (it's going to be a real task, I can tell). I haven't gotten into the front of the boat yet to inspect that end (and I'm dreading it).

2) I though boat builders used closed cell foam, so it wouldn't absorb water. Any thoughts? or does the closed cell foam break down over time, then absorb water? Trying to figure out why it's waterlogged (besides the fact of a small crack in the hull, that I'll be fixing).

3) Can anyone recommend any "new type" yellow foam, to ahdhere the white floation blocks into place (that won't become waterlogged over time)?

Thanks,
Troy
 

DanB

Crabber
I’ve never encountered open cell foam and I have had a couple of boats from that time period. The yellow foam I’ve seen I identified as the two part closed cell foam. Two part is what Sunfish/Laser was saying to use for repairs in their instruction handout from dealers. I think even cheese whiz foam in a can is closed cell, at least the Dow brand. Probably just lighter weight – thinner walled since moisture around the house isn’t likely to come anywhere near the meaning of moisture where boats are involved. Closed cell foam will take up water under certain circumstances. I remember reading something by Dow posted at one of the floating dock webs that talked about their testing. There are some directions for removing and replacing attachment foam at WindLine sales ( http://www.windline.net/project3.htm ) and several articles with diagrams at Sunfish Sailors ( http://groups.yahoo.com/group/sunfish_sailor ). Look for a direction sheet by John Howard, he took a lot of photos when he did his repair and names a supplier for the two part foam. IIRC its U. S. Composite ( http://www.uscomposites.com/foam.html ). Email or post to John H. and the others they have done some pretty heavyduty repairs. Repairing your leak and keeping the innards dry is your key to preventing waterlogging.
 

Gail

24186
The yellow foam is a two-part expanding foam that was used as glue to fix the white Styrofoam in place. The Styrofoam is the structure and strength of the hull and holds the top and bottom apart. Both the Styrofoam and the expanding foam absorb water. Patience, heat and lack of humidity will dry the foams out again. Those in a rush work to replace.

I have not ever heard of ants going actually into Styrofoam. That likely would cause a need to replace because the Styrofoam is structural and if it's riddled with holes and weakened, it would not do its job.

The yellow foam is NOT the Home Depot foam in a can. That is a one part foam and absorbs even more quickly. It also does not adhere anywhere near as well nor stick as long and is recommended against.

The previous posting about instructions are the best ones out there, so read them, sleep on them, re-read them, and then develop a plan of action. Good luck!
 

Wavedancer

Upside down?
Staff member
As Dan and Gail imply, replacing the inner structure is a MAJOR job. Drying out the innards is relatively easy. As long as you fix the leak, you can dry out your boat over time and go sailing in the meantime.

If you use the 'Search' function, you will find lots of info on drying out a Sunfish.

Good luck!
 

dliebert

New Member
I just wanted to throw on an addendum for anyone inclined to ignore the fine advice above. I saw a ~20' center console boat on which someone used not just the standard "cheesewhiz" foam but the extra expanding variety of it to repair a hole in the hull that resulted from a hard grounding. The expanding foam totally deformed the hull, stretching the "repaired" side out in a big bulb, and resulting in a boat hull especially suited to going in circles. Use the expanding foam with great caution.
 

walnut

New Member
As Dan and Gail imply, replacing the inner structure is a MAJOR job. Drying out the innards is relatively easy. As long as you fix the leak, you can dry out your boat over time and go sailing in the meantime.

If you use the 'Search' function, you will find lots of info on drying out a Sunfish.

Good luck!
I have read more about drying hulls than replacing styrofoam. Should that give me hope that I may be able to dry mine out and sail along my merry way?
 

walnut

New Member
I have read more about drying hulls than replacing styrofoam. Should that give me hope that I may be able to dry mine out and sail along my merry way?
(I'm not sure how to reply so I will add it here also)
 

L&VW

Well-Known Member
Install a 6-inch inspection port, buy a 4-inch muffin (or pancake) fan ($10), PVC adapters sizing the 4-inch fan to a long 2-inch diameter pipe, which is inserted diagonally.

Or, install two inspection ports, and run fan continuously over the unsailing season. (Either way...).

:)
 

FairweatherNine

New Member
I too am drying out my boat. A neighbor wanting to get rid of it sold it to me for $100, if it takes some time to fix and dry out I'm good with that. Just hoping to get in one sail this summer :)
 

FairweatherNine

New Member
That is great! Congrats! Just be sure to fix the leaks before you take it out and get water in it again!
Thanks, just update for anyone else who has to do this. I put a 4inch vent fan in one port and cut a second in the bow for an exhaust. I also put a heating lamp (careful it can melt the foam) into the boat. 3 weeks later it is 90% dry as a bone. the heating lamp really did the job. Shame it took so long but I will patch up the two areas that need it and give her a coat of paint next spring then a summer of sailing awaits.
 

roadking514

New Member
I have two opening in my Sunfish and this fan from Amazon fits perfect. Just run it for a week with the other hole open and it will dry it out.

VIVOSUN 4 Inch 195 CFM Inline Duct Ventilation Fan Vent Blower
 
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