Hull floatation foam blocks

I wondering if anyone has experience with removing the foam blocks in the hulls and replacing them with Cubitainers.

I bought a 1986 H18 Magnum last fall and have been restoring it. The current foam floatation blocks are waterlogged and I figure they are adding significant weight to the boat and are a constant source of moisture in the hulls.
I have 2 access ports per hull so getting them out in chunks is doable.

I'm probably not racing this boat so rule compliance is not a huge concerns but would be good to know as well.

Thx

I’ve heard of people doing what you’ve described - cut/break the blocks into pieces and pull out through an access port. You’ll need access behind the centerboard trunk. It’s not going to be easy, the blocks are big and your access will be limited.

Another option could be to try to dry out the existing blocks. If you already have two ports in each deck, leave them open and get some air circulating inside the hull with a small fan for a few weeks.

If you do remove the blocks, you’ll want to replace them with some form of flotation. Some people have mentioned using bundles of pool noodles stuffed into the hulls.

sm

are the foam blocks normally visible from the standard port hole? ive never seen them on mine, no idea if they are still there or not. im a 85 or 86

So I pulled the old foam out. pretty gross. a full garbage bag from each hull. one hull's worth was 28lbs. 17lbs in the other. It took me about 40min per side. Only one scuffed knuckle! There obviously was some sort of bug in there eating the foam as there was tunnels all through them. Hosed it all down an vacuumed out the little bits. Clean as a whistle now.

I was fortunate enough to have access ports at the sterns to facilitate this. There was no foam in front of the centre board casings.

I'm going to install the reliance camping water jugs. these are 20litres each and they weigh next to nothing.. Less expensive than the Cubitainers from Uline. I did some rough calculations based on some buoyancy formulas that I found on the internet. It would seem I could get away with one per hull. my Laser came with 3 of them so I will probably put 2 or 3 in each hull.

They are behind the dagger board trunk. You might need a mirror and flashlight or a cell phone camera to see them because of the angle, but they are large, impossible to miss if they’re there. Probably about 5 feet long and take up 1/2 - 2/3 of the hull volume. May be in a clear plastic bag.

sm

Foam blocks aren't for floatation, water tight hulls are for floatation. Foam blocks are to stiffen the hulls. If they are loose in the hulls, by all means remove them. If they are glued in place, you can circulate warmed air or dehumidified air through the hulls to dry them out. This is a common problem with Sunfish sailboats.

_________________
Yet another Bob!
"Firefly" - 2012 Hobie Getaway with wings and spinnaker
"Icebirds" - 1974 Skeeter iceboat
Too many canoes and kayaks

I cannot speak to Sunfish hulls, but on a Hobie, the blocks are 100% there to provide positive flotation in case the hull is damaged. They are not there to stiffen the hull, they are not (nor are they supposed to be) attached to the hulls. The only reason to remove the blocks would be if they have become waterlogged. In that case, you should replace them with another form of positive flotation.

sm

OK, thanks. I've seen cutaways of the 16 and it looked like they are backing to the glass. Hmm, maybe that's why soft Hobie hulls are such a common problem. They are deck supports on the Sunnie. Yeah, if they are just back up floatation, def get rid of them. Personally, I'd add airbags or not worry about it.

_________________
Yet another Bob!
"Firefly" - 2012 Hobie Getaway with wings and spinnaker
"Icebirds" - 1974 Skeeter iceboat
Too many canoes and kayaks

Two different things-

The hull and deck have foam cores. They are relatively thin, about 3/8” thick. That core is sandwiched between the inner and outer fiberglass skins. They will provide a nominal amount of positive bouyancy- not enough to keep the boat afloat if the hull floods. The foam cores add structure to the hulls while keeping things light weight. If the foam core separates from the fiberglass, then the hulls will become soft.

The OP was asking about the foam floatation blocks, which are not the structural core. These are large pieces of foam that are only placed inside the hull for the purpose of preventing the boat from sinking if holed.

sm

srm is correct: I was referring to the Styrofoam floatation blocks in the hulls, not the foam cores in the decks. The foam that I removed was definitely not adhered to anything, just bouncing around in the hulls.
Anyways, its all gone now. My cat is 40+lbs lighter and I can actually dry out my hulls. The Styrofoam was retaining so much water that there was constantly moisture on the inside surfaces.

And apparently its meal worms that like to eat Styrofoam. So now there's nothing to attract them either. Hosed out all the styrofoam bits and debris. Air bags are installed and ready to go.

Richard

1984 H18 Magnum
1979 Laser
19?? Tasar