Bayliner Bowrider - Is Flotation Foam a Structural Element?

[bdrw]

To refurbish the wet and semi-rotted interior of a 19? Bayliner Capri Bowrider, I removed the wood main deck and all of the underlying wet foam along each side of the hull. I would like to know if that foam was structurally important. I can replace the floatation capability without replacing that foam, thus keeping the cost down while minimizing opportunity for future water problems. Thanks.

 

[fishingdan]

Re: Bayliner Bowrider - Is Flotation Foam a Structural Element?

If the foam completely filled the cavity it was in, then it will add some to the structural integrity of the compartment. That said, it usually isn't in most production mass produced boats. What year/model is your boat?

Personally, I would replace the foam. I have rebuilt boats and have built 2 from scratch. In addition to floatation, foam has other benefits. One of the best characteristics to me is the sound deadening quality. Emply space make a lot of noise when running on plane. Fill those space with foam and the boat sounds like a very different boat. In fact, the sound influences your perception of the strength of the structure. To a degree it actually does.

The tricky part of foam is to do it right. Closed cell USCG approved foam is expensive, but nothing new there. I always fill a compartment 100%. You may need to plan for water passage depending on the hull design. The only compartments that I have had problems with are those that have been only partially filled with foam.

 

[bdrw]

Re: Bayliner Bowrider - Is Flotation Foam a Structural Element?

Thanks - it is a 1987. Because of the rot problem, I have considered foaming the sides rather than replacing the foam under the deck where it gotten saturated before.

I believe the water infiltrated through the dual seat assemblies on both sides. The boat had been exposed to the weather and there was considerable deck rot as well as rotting of the seat support structure.

I appreciate your mentioning the noise issue.

 

[bigbad 4cyl x2]

Re: Bayliner Bowrider - Is Flotation Foam a Structural Element?

isnt us composites still selling cheap foam kits

 

[emilime75]

Re: Bayliner Bowrider - Is Flotation Foam a Structural Element?

I hate to get off topic here, but I haven't read you mention the transom at all so far. If the floor is in as bad a shape as you state, it's very likely the transom is no good either. It would be a shame to do all this work putting in a new floor and foam and then find out the transom's about to fall off the back of the boat. Just something to think about. Aside from that, foam was used in a small percentage of makes/models as an additional structural part of the hull. And as fishingdan said above, it really does help with sound deadening which makes the boat more comfortable to be in and it adds to the perception of a solid, well built boat.

 

[ezmobee]

Re: Bayliner Bowrider - Is Flotation Foam a Structural Element?

A lot of members down in the restoration section are replacing their saturated foam with the pink or blue sheet foam from Lowes/HomeDepot cut and shaped to fit. It will not hold water even if it gets wet for extended periods. Wheneven I tackle my next resto that's the route I'm taking.

 

[rodeo brody]

Re: Bayliner Bowrider - Is Flotation Foam a Structural Element?

Fishingdan touched on an important point.
You should fill each space 100 %. Especially in the floor where water
could infiltrate. If there are any spaces at all water will get in there and
just sit. I talked to a Nautique salesman and he told me they pour the expanding foam between the stringers before putting the floor in. They shave the excess off with a big knife at the top of the stringers. That way there are no small cavities for water to sit and rot the new floor.

 

[bdrw]

Re: Bayliner Bowrider - Is Flotation Foam a Structural Element?

Thanks for the suggestions.

I have considered a passive approach to the flotation replacement issue which does not address the noise issue (which I believe is worth considering).

So long as the poured foam is not required structurally, I would leave a sealed void under the new deck where the foam had been originally. I would create a covered access port into the deck on each side, then fill the void with packing peanuts. After each use of the boat, I?d open the ports to vent any moisture. If the space ever got wet, I?d just remove the peanuts with a shop vac, let the space dry, and put in more peanuts.

Clearly, the peanuts would leave voids, but in water where hypothermia is the bigger threat simply sealing those sections would seem to provide plenty of float time in the event flotation properties of the boat were ever put to use.

 

[109jb]

Re: Bayliner Bowrider - Is Flotation Foam a Structural Element?

Lots of packing peanuts are made from starch and will disappear over time. Only polystyrene peanuts would have any chance of working and I don't think they would work well at all.