To Foam or not to Foam?

[BuilderFL]

I’m trying to raise the stern of the V a few inches and I can’t quite determine if filling the inside cavity of my outboard bracket with 2# closed-cell foam (added buoyancy) will accomplish that. Your comments and expertise, as always, are very welcome.

[macojoe]

It will not raise you at all!

If it is closed right now thats all you need for floation, and if it isn't closed and you add foam then you have added floation, but thats it.

Only way to rasie it is to lighten the load, or add trim tabs to help when under way.

[Skools Out]

add sand bags in the front under the floor somewhere like the mfg do.

[bradford]

If ya foam it and it doesn't seal right it will waterlog and you will have worsened your problem.

[twistedparrot]

i gotta disagree with you on that bradford. i am drinking coffee from a foam cup as i type this. a cc foam of 1.7 pound density or greater should only transfer no more than .001 perms. there fore it will not absorb water as would a foam with an open cell structure. that is why we apply closed cell foam for floation and insulation in the hatteras, and other high end boats, for trinity yachts.

mj is right. in theory, a sealed structure will not gain any boyancy by adding foam, or any other material for that matter. but most boat builders use it in thier boats. and if you ever do get a leak, it will keep the water out. plus it does add stregnth, especialy to fiberglass.

i would not recomend the application for the do it urselfer with a froth pack. spray applying can be tricky enough. pouring the foam requires the proper equipment, training, and experience. these chemicals are applied at 120-140 degrees and heat to much higher temps after the iso andresin has mixed. and the tempreture of the substrate must be controled. if applied in more than 1.5-2 inch lifts the material will over heat and loose it integrity, or possibly catch fire. the materials expand to 30 times its original size when mixed and will buckle steel and split aluminium with ease if not applied right. also be sure to 'kill' the bolts to the structure, cause you will never see them again.

foam is a good idea where ever you can put it, if applied correctly. foam the world, thats my motto

[spareparts]

Builder, search for some 23 Formulas that have had bracket conversions, I've seen a couple that had the add on swim platforms(saw one that used transom mounted live wells converted for floatation) on each side of the bracket that added bouancy to the bracket. They generally don't have floatation on the platforms from the bracket manufactures, but the ones I've seen on the Formula conversions do, I don't know if it was custom or factory made. I you added the factory platforms, you could build floatatoin chambers under the platforms, you could get a couple of square feet of floatation out of them, I don't know if it would be enough.

[kamikaze]

BuilderFL:

Skools has the best suggestion given that you just went through a refit. Since I moved my tank upfront the ride is completely different. You would be surprised how much effect two 50 bags of sand have when placed up underneath the casting deck as far as possible.


However, as a result of relocating the tank, I now need to raise my bracket UP 2.5" to 3" as originally suggested my the manufacturer. (Although I mounted it up 2.5 inches at first, I lowered it to keep the cavitation plate even with the keel - in a failed attempt to to correct the issues with spinning out the prop)

So as a lesson learned the hard way. When adding a bracketing a center console you need to add weight upfront ( a lot more than you might think) and mount the bracket so the cavitation plate is 2.5 to 3" above the keel.

Kamikaze

[BuilderFL]

Kami, you're so right and the lack of that additional weight in the bow is why I've been having problems with my prop and my ride. Since I've had to dismantle my t-top and console to repair the damages by the SOB (see gallery) that stole my electronics, I’ve gone back to the board with the weight and balance as well as the center of gravity and buoyancy issue. Preliminary results: Either add 750 # of foot-pound (150# 5’ from the bow) or move the console forward to 8.3’. In my case, I’m moving the console forward one foot so that the center of the console is 11.5’ from the bow and adding about 80# 5’ from the bow. My CG should be at 12.66’ from the bow-not bad for an almost 23’ boat (considering the bracket.) Want to really get into weight and balance, check this out:
http://microship.com/resources/cg-weight-study.html ::) ::)

[msbhammer]

Your not gonna pull the bracket are ya ???, just add a jack[late to the brackey.

[BuilderFL]

No, the bracket stays and it already has a jack plate. The issue has been weight and balance. Too much in the stern. As a matter of fact, once I redistribute my weight, I might want to take the jack plate out and move the motor forward those 10 inches.