[relicshunter]

I'm trying to get a better understanding of this subject, so does it actually add boyency to the boat if its below the water line or is it strictly there for the oops my boats plug got left out moments?
thanks for any help

 

[tomahawk]

Its there to float the boat, persons and equipment in the boat when swamped full of water.

 

[firecat1981]

It will not add buoyancy under normal conditions. It will save you and your boat when things go wrong though. It's mandatory in my mind.

 

[DuckNut]

I adds weight to your boat causing it to draft more when the boat is does is not full of water. Fill it with water and you will understand why it is mandatory.

Tie a beach ball to the end of your anchor line so you can direct the salvage company to its location.

 

[WhiteDog70810]

Best explanation I've heard: the foam takes up space in the boat that would otherwise fill with water when swamped, allowing the hull to support the motor's weight and float level when swamped instead of capsizing and following the motor to the bottom. The foam is still denser than air, so it has no benefit under normal conditions when the hull is not full of water.

Nate

 

[CurtisWright]

about to say the same thing.   It takes up space to prevent water from comming in.   

In my boat I want to make big sealed void spaces with their own plugs to drain any water that accumulates.  It should do the same thing but weigh less.  Same concept as flotation in a white water canoe.

 

[DuckNut]

make big sealed void spaces with their own plugs to drain any water that accumulates

Yes, unless they get a crack in them and then you have problems.

Fill the void by gluing foam to the top of the inside of the box leaving an inch of space when you build them.

 

[firecat1981]

Foam filled spaces are more for catastrophic impact issues then just swamping. Like hitting a log or oyster bar at speed. Without foam filling the void space will fill quickly, with foam you should be able to limp back to the dock.

 

[CurtisWright]

make big sealed void spaces with their own plugs to drain any water that accumulates

Yes, unless they get a crack in them and then you have problems.

Fill the void by gluing foam to the top of the inside of the box leaving an inch of space when you build them.

I have been deeply considering this. Heres my logic. If I hit an oyster bar or stump or something of that nature it should mean that I am in shallow enough water that it wont sink all the way or I am close enough to shore to get the boat up on the bank and deal with it there.

I am most scared of taking a big wave over the bow or stern. I think it would be very beneficial to have a sealed front and rear compartment so that I would still float and be able to plane even if I take a wave on.

I have just enough foam in the boat to keep the motor from sinking, but would like to have the security of a Whaler in the shape of a flats skiff.

 

[WhiteDog70810]

make big sealed void spaces with their own plugs to drain any water that accumulates

Yes, unless they get a crack in them and then you have problems.

Fill the void by gluing foam to the top of the inside of the box leaving an inch of space when you build them.

I have been deeply considering this.  Heres my logic.  If I hit an oyster bar  or stump or something of that nature it should mean that I am in shallow enough water that it wont sink all the way or I am close enough to shore to get the boat up on the bank and deal with it there. 

I am most scared of taking a big wave over the bow or stern.  I think it would be very beneficial to have a sealed front and rear compartment so that I would still float and be able to plane even if I take a wave on.

I have just enough foam in the boat to keep the motor from sinking, but would like to have the security of a Whaler in the shape of a flats skiff.

"Oh chit" moments do not care about logic. Every boat can gut itself on a submerged pylon on the way to the shallow stuff. Sealed compartments are lagnaippe only, nothing more. Safety measures should be redundant and as bullet proof as possible. Personally, if every sealed compartment of my hull fails, I still want the boat to float level, hence the foam in every one of them (suspended over any moisture that may accumulate) and suspended under the decks. I do need to install drains and plugs in all of the flotation compartments since I firmly believe "sealed" compartments on boats, at best, are temporary vacuums waiting to be filled and, at worst, are merely entities of fable and legend.

Nate

 

[firecat1981]

but would like to have the security of a Whaler in the shape of a flats skiff.

They already make that, it's called a carolina skiff

Your logic is sound and flawed at the same time, in perfect planned conditions you may be able to self rescue, but you may not know you have a bad leak until you are headed back to the dock in deeper water. Remember to plan for the worst and hope for the best.

Taking big waves over the bow is not a big deal to me, that's what I have the bilge pump for. I've had 4" of standing water, plus whatever was in the bilge and chases, in my skiff after taking a huge wake from an jacka$$ and wasn't worried. Pump kicks in and a few minutes later we kept fishing. But I know I can totally swamp my skiff and it will still float fine because of the amount of positive floatation I have in it.

There is something else to consider with large void spaces, without foam filling it you have a huge void of just air. If sealed, especially in warm climates, the air will expand and contract on hot/cold days and warp, crack, or rupture the surrounding areas over time. Filling the void eliminates the air space and will prevent this. Or you can add a weep hole, but that defeats the purpose of a sealed space, and if you plug it you have the same issue of expansion on warm days.
I didn't know all this until it was explained to me by Jacques from BBC when he was critiquing one of my designs.

I've used styrofoam sheets in the past with great results, but the closed cell pourable foam the have these days is way better then it used to be and I am quickly becoming a fan.