Floatation Foam

Can I swap out the old, stock styrofoam floatation that is strapped in via glass under the seats to newer stuff like the DOW styro-like, blue logs that dock builders use - without affecting class rules ?

Thx

I have done this using the DOW Boyancy Billets. One eight foot by 10" by 20" billet will provide 600 pounds of flotation which is what is required of the top deck. These billets are Corps of Engineers approved for house boats and docks.

Blue Grass,

The original layout is about 7.5" thick ( 2 pcs of 3.75" foam stacked ) x about 12" wide and about 4.5' long.... <---------- there are (2) sets of these that make up one side of the underdeck.

Would you need (2) of the 10x20x8 ? for both sides of the deck ?

Or, did you cut the Dow material in half? If so, with what ?

It seems that (1) pc of the Dow stuff, if cut in half, lengthwise, would 'just' get the entire job done. The overall dimnesions of the DOW foam would be smaller than the original footprint - but I guess it all boils down to buoyancy.

Are you sure your spec is accurate ?

Thanks !

Yeah, the reason they stacked them is probably because that is how the old styrofoam blocks came from where ever they were manufactured. The new Dow Billets have a little better boyancy than what was under my 1985 boat deck, which was not much better than old chest cooler foam.

It doesn't really matter the size here as long and you get the required 600 pounds of boyancy needed by the boats design. The boat weights around 850 pounds, minus the 600 for the flotation blocks, which leaves 250 pounds of boyancy needed to float the boat. This is where the Balsa core provides the reamaining amount.

Yes, I cut mine in half and then long ways after that to get a size the would fit behind the seats. I used a crosscut wood saw, but I think you can rent a hot wire melting saw that might be ideal.

One more quick question :

How did yo mount the foam back in place ? Did you use fiberglass straps like the original set-up ? Re-glassing straps seems easier if boat were upside down - which is not an option.

Cut out the old fiberglass cloth using sheet metal shears. Remove the old foam, and then use wooden props or sticks to hold the new billets in place. Using at least 50 pound test nylon strapping or cord (knotted or folded at each end), apply fresh resin fiberglass cloth over each end of the strapping. You will use these in place of the old flotation support. Important: Sand and clean with Acetone the hull at each spot where you will attach the ends of the strap with fresh fiberglass. I used a masking tape to hold the new resin fiberglass and straps in place while they bonded to the hull. You can peel the tape off later. Remember, each of the four cut billets will provide 150 pounds of float, so they should have at least four straps each to support them if the boat is turtled. This also would include a strap on each forward and aft end to prevent the billet from slipping into the foredeck or afterdeck on capsize. I hope this helps.

Your description gave me an idea. I will get the DOW stuff, cut it to dry fit - use your prop up idea - then I will lay up the correct lengths of glass roving "straps" - several layers of light roving fiberglass.

Then put these straps on a flat pc of plastic covered plywood. Wet the glass out - LEAVING each end of the straps, 3" or so on each side, UN-WETTED. Let this kick and harden.

Then, with DOW foam in place, tape the hard, flat straps in place and resin/wet out the unresined glass ends in place.

What do you think ?

phebejim's picture

Consult Flyingscot.com. They can supply a kit for securing flotation which includes seat belt type nylon webbing---a stronger set up.

 The FS supplied seat webbing kit is for a fore and aft securing of the foam blocks.  I need to secure the foam the way it was done originally - fiberglass straps that run starb to port ( or vice versa ).  

phebejim's picture

I think Flying Scot determined that the port to starboard fiberglass straps were not sufficiently sturdy in rough conditions---the foam came loose. So they advised adding longitudinal straps to the port to starboard ones.

phebejim's picture

I think Flying Scot determined that the port to starboard fiberglass straps were not sufficiently sturdy in rough conditions---the foam came loose. So they advised adding longitudinal straps to the port to starboard ones.

Put a strip of wax paper between the foam and the glass strip to keep it from dissolving the foam.

 Wax paper good advice.  I was going to use plastic but wax paper just as easy.  There is a lot of prep before I actually glass foam in.  The way I see it:- cut foam to fit.- cut pcs of scrap wood to hold all the pcs of foam in place ( I'll be working with boat right side up not upside down )- pre-glass several pcs of long narrow glass on a veneer table - leaving the ends un glassed- sand areas to be glassed - tape wax paper in place.- let resin get more tacky than usual for the upside downwet out - and glass fiberglass strips in.Sound about right ?