FLOATATION FOAM

Hello H16 world,
I drilled all the softspots on the deck with a grid of 1\4 in holes. I punched through the bottom side of the sandwich on many of the holes, so can I just fill the entire hull with floatation foam and then hit the holes with resin as planned?

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styrofoam Snark
AMF Dolphin
OBrien Windsurfer
Sunfish
1983 Hobie 16
Hobie Adventure Tri
Hobie Proa project

This would make the hull too heavy.

Where you drilled clear through you will need to plug the hole at the bottom of the sandwitch so the filler (GitRot is what I use) will stay between the layers.

Now how do you plug the the lower hole? Maybe silicone the original top/bottom holes and redrill the top part when it has hardened. It would need some cleanup whith a bent nail to make the GitRot flows beetween the layers.

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1979 Hobie (sold)
1983 Hobie 16 Hawiian Sunset (sold)
1981 Hobie 16 Tequilla Sunrise - still own
2008 Hobie 16 (currently sailing the crap out of this boat)
1977 Super Sunfish
Founding member of the "San Dimas Yacht Club"
John

thanks,

I guess i'll stay away from the floatation foam.

i was going to use an allen wrench mounted in my drill to clear a radius inside the sandwich to create a space to accept the resin.

so i need to stuff the push through holes with silicon. can you recommend anything else. how bout some micro balloon thickened resin.

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styrofoam Snark
AMF Dolphin
OBrien Windsurfer
Sunfish
1983 Hobie 16
Hobie Adventure Tri
Hobie Proa project

You could use thickened resin to plug the holes, and drill new holes nearby through only the top layer to put the gitrot.

When you drill, put your drill speed really really slow.

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Marc...
1978 Hobie 16 Keoke, sail# 36 84

http://www.fibreglast.com/product/2_Lb_ ... 7QodXAKoGA

the foam is only 2# per cubic foot. this doesnt seem like much of a sacrifice because the hulls already have a v-shape solid styrofoam insert. the styro is probably 2 cubic feet.

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styrofoam Snark
AMF Dolphin
OBrien Windsurfer
Sunfish
1983 Hobie 16
Hobie Adventure Tri
Hobie Proa project

I recommend a dremel for making the holes. You can hold the dremel like a pencil so you get a lot more control, and it has variable speed control. It is also light so the weight of it wont push like a regular drill.

Once I did the same thing, i drilled to strait through all layers, but did not notice. I then injected 4 oz or resin strait through the deck. It landed on the foam block. I kept thinking wow the soft spot is taking a lot of resin, then I realized what was happening.

Also I've read about a few guys who had there hulls completely filled with expanding foam. They said it leaves the hulls super stiff and only added 20lbs per hull. So it is doable and practical if you have a very old boat, that needs some stiffening. Viagra works wells too.

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ALLEY CAT 1984 RED LINE HOBIE 18 MAGNUM
Sail # 10505 or 277

Filling the hulls with foam is a really bad idea.
1) Adds weight. 20 lbs is significant.
2) You can't fill every void without exploding the hulls.
3) If you can't fill every void, every void will eventually hold water - which adds more weight.

There are other problems, too. This has all been discussed before, and there's even a real world example - the Sizzler.

The Sizzler was made from hydroformed aluminum sheets and filled with urethane foam. They worked great until they invariably leaked. They took water in and never let it out. They got heavier and heavier and heavier.

Sure, "filling" the hulls with foam will work for a while. But it's bad for the boat in the long term - and for resale value.

ok, so to do it right you would need to pull the whole deck and install the expanding foam. no thanks.
I will go back with a dremel tool and some thick resin.
Any advice on filling the push throughs??

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styrofoam Snark
AMF Dolphin
OBrien Windsurfer
Sunfish
1983 Hobie 16
Hobie Adventure Tri
Hobie Proa project

Just fill them with thickened (very thick - peanut butter thick) epoxy. Use microbaloons or colloidal silica (Cab-o-Sil).

If you take your drill bit and wrap masking tape around it (about 15 times) only leaving an 1/8" or less sticking out... it works quite well....

i also used an dish soap bottle to fill with my epoxy ... the nipple on the end fit right in the holes, and i could squeeze the epoxy into the voids...

another tip... mask off everything you don't want covered in the stuff.. to do a good job you make quite a mess....

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•Present boat -1998 Hobie 16 Solana Sails furling jib[/size]

20 lbs is not significant if you do not race, and if its a very old boat, who cares.

Not every void will hold water, the mistake with the sizzler was the foam was not water proof. That allowed water into voids, which could not be removed.

If you did use waterproof foam the voids or the foam would not take water.

Expanding foam is only a last option for a very very old boat, in a location where you can't get hulls.

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ALLEY CAT 1984 RED LINE HOBIE 18 MAGNUM
Sail # 10505 or 277