Will removing foam under floor make boat unstable?

[snake91876]

I have redone a 1987 bowrider that is about 8' at the beam. the boat had tons of rotted foam i took out from under the floor. ive heard all the stories you need it but only use my boat in the lake and did not feel the need to put it back in. Now it seems like the boat rocks or leans to one side when you walk around in the back. Keep in mind this is a deep vee style imperial bowrider not a very good boat design to start with. Do you think me taking out that foam made the boat more unstable and if i put some back would it be more stable.

 

[erikgreen]

Re: Will removing foam under floor make boat unstable?

If the foam was wet when you took it out, the boat may very well be a lot lighter now, which would feel more "unstable".

When it was in the boat and dry, the foam likely added no more than 2 lbs per cubic foot of weight, and no buoyancy (foam doesn't add buoyancy unless the hull is submerged).

Wet, the foam could have weighed up to 10-20 lbs per cubic foot, depending. With that much weight gone the boat would rock and move more easily.

If the foam was structural (you don't say whether you're rocking in the water or not) then you need to replace that structure to stop any wiggling.

Erik

 

[solar7647]

Re: Will removing foam under floor make boat unstable?

I wouldnt think the removal of the foam would make it unstable but it may have messed with your weight distrabution. I would try to adjust your weight a little, you may just have more weight on that side that it is leaning to. I believe the foam is there just to keep it semi floating in the event of hull breach..


Does it lean to one side more then the other...? What about if you stand in the center at the stern?

 

[Bob_VT]

Re: Will removing foam under floor make boat unstable?

Stability??? The foam has no effect while afloat unless you are sinking..... it has a more severe impact on liability.

 

[Bondo]

Re: Will removing foam under floor make boat unstable?

Now it seems like the boat rocks or leans to one side when you walk around in the back. Keep in mind this is a deep vee style imperial bowrider not a very good boat design to start with.

Ayuh,.... Just How much of it have you put back together,..??
The hull will get stiffer,+ stiffer as you reconstrut it....

I don't know your hull,...
It'll entirely Possoble that the design relies on the foam for substantial amounts of struture,+ strength....

 

[Lou C]

Re: Will removing foam under floor make boat unstable?

This is a subject that's been discussed a lot here...when I did my 88 FW 200 I contacted FW and asked if the foam was for structural support as well as flotation and FW said yes it was structural so I had to replace it...looking at the stringers in this boat there are 2 on each side and one below the ski locker...but only 2 transverse bulkheads...boats that do not have foam from the factory have a lot more transverse bulkheads...
When I got it done and took it out on the water I was pleased by how solid and stiff the boat felt...
Rocking at rest is a function of a deep V hull design...and if the foam was water logged it may have well been a lot heavier and sat lower in the water...but not being a marine engineer I went with what the people who built the boat told me....

 

[bigal7733]

Re: Will removing foam under floor make boat unstable?

He folks how did all you guys remove all the foam from your boat? What tools worked best? I am a Marine Tech student rebuilding a 1972 19 foot reinell and all the foam was/is WET!

Thanks!