Flotation in an old 19-6

[kleary4]

I have a 1975 19-6 and love it.  I worry though, that the boat has almost no factory flotation in it.  So even if the hull is roughly neutrally buoyant, once you add the 400lb 4-stroke outboard and T-top, the I figure the thing is definitely a sinker.  I think about this more now since an old hull patch failed last season, and caused a leak that my bilge pump couldn't keep up with.  So:

I'm looking for alternatives to pourable or sprayable foam.  The hull isn't designed for it, so I figure that I'd just make a mess. One alternative:

There's tons of room under the sole and in the sides of the hull that is easily accessible through deck plates.  I could slide in Kayak Flotation Bags, and blow them up.  I think the inflated volume is about 20 liters, so 10 of them would give me 400+ lbs of floatiness.  They'd be serviceable, with no possibility of getting waterlogged.  Does anyone have any thoughts on this one?

[RickK]

I think that the newer closed cell foam is fine under the sole. If you're worried about the existing foam I would cut out the sole and remove the old foam both inside the hull and inside the stringers.  Then I would inspect the existing stringers and their bod to the hull - repair as needed. Then replace the old open cell foam with the closed cell type.  Then you will have the safety you're looking for. The hull was designed to be self-bailing with the top of the sole being isolated from the bilge. As long as you can keep water out of the bilge you should be fine with new foam.

[kleary4]

Thanks Rick.  In my '75, there is really no evidence that there's ever been any flotation in the hull at all.  Pulling the deck plate in front of the console shows nothing but nice clean glassed-in stringers and the front of the fuel coffin - again with no foam anywhere to be seen.  I replaced the fuel line from the filler to the tank and it was a breeze.  No foam.  So I think we're starting from scratch here.  Summer is short here in the North, so I don't want to do anything to put my season at risk.  I think I'm going to order a couple of the flotation bags and see if that approach has a chance.    Cheers.

[RickK]

Usually the foam is on the other side of the stringers between the hullside and the stringer.

[Capt. Bob]

I'll assume you know this already but it bears repeating.

The lightest flotation media is air. When weight is a concern, air is much lighter than foam but...
A breach in the hull cavity is quickly filled with water when there is only air present. Foam doesn't allow water to displace the air and is a much better medium for flotation. As you have seen and Rick has referred to, early Aquas used air rather than foam.

My 1991 Genmar hull has no foam except in the stringers. It relies on air trapped in the hull and the cabin (I guess) to meet the Coast Guards flotation standards at that time. If I ever rebuilt the deck, I would fill the open space with HD foam. Yes, it adds much more weight than air but it gives you a much higher confidence level. 

Good luck.

[Fish Head]

I stuffed 120 pool noodles below my deck for extra flotation besides the new 2 part expanding foam that I replaced in the stringers during the rebuild. Pool noodles are PE closed cell foam that will only degrade from UV light/sun. Caught a sale at dollar store buy one get one. I found a formula somewhere  online that calculated how much weight a noodle would float. I think I remember 120 noodles would float 1000 pounds. I know 2 will float my fat ass lol! I figure between the 2 my 1972 19'6 will not completely sink although will probably submerge just below the surface worst case. Foam insulating sheets from Home Depot or Lowes are also PE closed cell foam and are not that heavy. I figured with the pool noodles there is air channels for ventilation to dry out water that might make its way below the deck?I also did my best to replicate the original theory of making the deck completely water proof from above and have a self draining deck. So far so good for the last 2 years, all dry below. Gemlux scuppers with the duck bill inserts have worked flawlessly.

[RickK]

Fish Head I can only guess the response from the next person that opens up the sole in that boat and sees all those pool noodles     

[NOTRUB]

Not sure I understand any of this foam flotation thing.  The only boat manufacturer to do this was boston whaler.  There is a very good reason u do not see old ones.  The foam gets wet and rots the inside.   The worst offender to water getting in my boat is condensation.

[Fish Head]

Hey Rick yeah I have often thought when we are chillin at the sand bar for the day I could start pulling out pool noodles and have a float party with about 50 people or so  .
PE closed cell foam should not absorb any water. Up here in the North my boat sleeps in the garage during winter and most of spring. Michigan rarely has a weather wise enjoyable spring time. So plenty of time for hull to dry out if need be.
I came really close to sinking her on a day with 35mph winds years ago! Fish were biting what can I say lol. We took 5 giant waves over the transom in about 5 min. 2 bilge pumps and scuppers could not keep up. Transom almost dipped below the waterline. We were drifting so I got the motor started and sent my 3 buddies to the bow and we got out of a bad situation. This was before the rebuild and I believe she would have sank fast. This day got the rebuild put in action.
So unless my stringers crack or separate from hull the foam should never see any water in them. I was getting concerned about weight of hull because I did overbuild and added a lot of extra cloth and epoxy reinforcing everything. I figured the pool noodles were cheaper ,lighter and no chance of breaking down and becoming open cell foam like the 2 part foam. Not sure that is true but the original foam in my stringers was completely soaked like a sponge.

[kleary4]

Pool noodles . . . wow, I like that idea!  And yes, a bit of math plus a unit converter gives 245in^3 or 8.5 pints of displacement each.  Since a pint is a pound the world around, you got exactly 1,000 lbs of extra floatiness in there.  I think I'm sold.  Thanks!