Foam

[Bob M]

We sold our 37' trawler and want to cruise in a much smaller boat, a 1973 SeaCamper, a project boat. I've removed the rotted transom and stringer wood and am nearly finished removing the bilge Styrofoam, the cause of the rotted wood. The Styrofoam retained water, which rotted the adjoining wood.

Except for minimal cabin sole support, the Styrofoam provided no structural benefit. The only benefit I can see is water displacement, should the boat sink.

There are probably better foams to use these days than Styrofoam. I've seen 2 liter capped bottles recommended instead of foam. Another recommendation was to carry a life raft and forget about adding displacement to the bilge.

I'm hoping to add center-bilge tanks to the boat (fuel, water and sewage), which would take up considerable space formerly displaced by Styrofoam. These tanks aren't likely to be empty, so the displacement value of the tanks would be minimal.

Water displacement foam, bottles, or nothing?

 

[sjisailor]

Unless I'm missing something, the foam would only do anything (add buoyancy) if the bilge fills with water ... in which case I don't think it would help enough because there's a bigger problem! So my inclination would be to concentrate on good bilge pumps, hull condition, and dryness, and not mess with foam or bottles (how many would it take?)

Although if you have one, a photo of the situation would be helpful.

 

[Bob M]

Unless I'm missing something, the foam would only do anything (add buoyancy) if the bilge fills with water ... in which case I don't think it would help enough because there's a bigger problem! So my inclination would be to concentrate on good bilge pumps, hull condition, and dryness, and not mess with foam or bottles (how many would it take?)

Although if you have one, a photo of the situation would be helpful.

Thanks for the reply.

This is a photo looking forward. The rotted stringers are still in the boat in this photo. The sole is partially removed in this photo. When looking forward at the Styrofoam in the center bilge area, you can see voids and deterioration at the lowest bilge point. The white sole area forward is molded fiberglass, which I'm not planning to remove nor the Styrofoam in this forward area.

 

[Mac2]

Don’t you think the styrofoam was for insulation rather than buoyancy?

 

[DNT99611]

It has been my experience that even the closed cell foam will absorb water. It does help stiffen things up and helps with noise. Like many things it is a give and take deal. I am a fan of water tight bulkheads myself.

 

[HeadedToTexas]

That's a head scratcher. Perhaps the foam was there to replicate Boston Whaler ads from the time period? Respect for Boston Whaler aside, I'd leave the foam out and leave the space open for panel access from above.

 

[sjisailor]

Agreed with the other responses. It may have been more for insulation and/or noise, since the SeaCamper (very cool concept!) was proposed as sort of an RV / Boat hybrid. Over the years some folks have also thought that foam would help keep a drier bilge ... but it seems more to just hide moisture.

Personally, I'd get rid of as much foam as possible and leave it open to stay dryer.

 

[Bob M]

It has been my experience that even the closed cell foam will absorb water. It does help stiffen things up and helps with noise. Like many things it is a give and take deal. I am a fan of water tight bulkheads myself.

 

[Bob M]

It has been my experience that even the closed cell foam will absorb water.

One more negative for foam, and a big negative.

Much of the water saturated Styrofoam in the middle bilge area was still frozen when I removed it July 1st. There are enough foam negatives that I won't put foam back into this area.

This SeaCamper is unique in as much as it has two lateral bottom hull channels that extend upward into the bilge. Carpet covered boards on the trailer slide into these channels. The channels create three lateral bilge areas with no flow of water between them. For the two starboard and port bilge areas, I'd either have to install bilge pumps aft, or fill them with foam. I removed the Styrofoam from these outside areas and it was dry.

Two rotted stringers further divided the middle bilge area and terminated aft at the transom. When I replace these stringers, I'll create two aft channels so water can flow into the middle-middle bilge area, the area certain to have at least one bilge pump.

I'm still scratching my head about how water got into the bilge to start with. An explanation that seems plausible is that the boat took on water while on the trailer. If the trailered boat was parked on a hill, water could enter the engine room hatch, flow into the center bilge area and from there flow forward. The transom wood was nearly completely rotted, so another plausible explanation is that water could possibly have entered while in the water, most likely from the engine water intake that went through the transom; the transom area around this opening was the consistency of dirt.

I'm rebuilding the transom. An outboard motor mount is planned for this former I/O boat.

 

[DNT99611]

Having done rotten transoms a couple times you will be better off if the wood is totally rotten. If it is just wet and a little soft it is much harder to remove. Does not make much difference when working on the stringers. It is a long and messy job but it does not take much brain power

 

[Bob M]

Having done rotten transoms a couple times you will be better off if the wood is totally rotten. If it is just wet and a little soft it is much harder to remove. Does not make much difference when working on the stringers. It is a long and messy job but it does not take much brain power

With the exception of the rotted transom wood below the integral steps, the rest of the rotted transom wood and stringers have been removed. The wood below the steps is difficult to get at and will be tomorrow's clean up emphasis.

I counted holes in the transom; there are 50. It's my guess that all 50 leaked and there's no mystery about why the transom wood rotted.

The photo was taken before all the through-transom bolts, screws, etc. where removed.

The top surface of a new outboard motor mount platform may be able to match up with the bottom integrated step. If so, the fold down step may be eliminated and replaced with a fold down ladder off the platform.

I'm reluctant to attempt to both design and fabricate an outboard motor mount platform. Any suggestions for a designer and fabricator?

 

[CharlieO.]

On Youtube look up "AYO fishing" he restored/rebuilt a small old houseboat and converted it to outboard power. Replaced stringers, transom, interior all the same stuff you're looking at. Below is a link to the series.

https://www.youtube.com/playlist?list=PLet55MHPbVFACZ59vFr00pnJtcAx6Ohqw

 

[Bob M]

On Youtube look up "AYO fishing" he restored/rebuilt a small old houseboat and converted it to outboard power. Replaced stringers, transom, interior all the same stuff you're looking at. Below is a link to the series.

https://www.youtube.com/playlist?list=PLet55MHPbVFACZ59vFr00pnJtcAx6Ohqw

Thank you for this.

 

[DNT99611]

PDR out of Washington builds them for SeaSport and other brands. They do nice work and mine was a perfect fit. That is how I would go for a factory built metal bracket. I also built a bracket out of glass for a 21 foot Sintes hull I built. When replacing the stringers I ran them out through the transom to support the bracket.