Sad that they put all this foam (sponge) in boats these days.

[Rojo]

If it is a recreational vessel with a Horsepower / Capacity rating it has enough foam (in the seats and bow) to float level if swamped. Commercial vessels are not required to do the flotation or be Coast Guard approved but they are not supposed to be sold for recreational use.

Slab, the second picture is what I was referring to, more transverse stringers as well as stringers located on strakes or other load (Lift) generating transitions in the hull. Also you want your decking to connect with the stringers running the main longitudinal run as well as in strategic transverse locations for torsional stresses.

[SuperDave336]

Brian Latimer did some videos of them building a new bass boat. Very cool to watch them all. Thought interesting when they joined them together and glued certain sections around 10:30 min mark.

[Rojo]

I saw these a while back. Good videos. Their stringer is totally another fiberglass molded part with foam filling.

[Linhardt]

I have always thought that plastic bottles would do good for flotation. Not the crushable water bottles. More of the heavier duty ones like with gatorade, powerade, etc. They are usually built stout and a little hard to puncture. I would think if you were to glue the lids on tight and stack them into areas as tightly as possible that it would work good.

It would take a long time for them to probably degrade, they should hold air perfectly and there is nothing for the water to soak into. I should just run between them and out the area. Only thing I could think of is the possibility of expansion and contraction in hot/cold weather. Might affect the bottle some or the area if packed too tightly causing some distortion. Or could rattle around some if not packed somewhat tight. But for aluminum boats I think this would be acceptable.

Now I have not tried it or currently know anyone that has, but in theory it should work great.

[Slab]

Brian Latimer did some videos of them building a new bass boat. Very cool to watch them all. Thought interesting when they joined them together and glued certain sections around 10:30 min mark.

Yep, he's the one who did that first video I posted. That's what I'm talking about. Unless fully encapsulated, and water tight, water's gonna get in and never come out! On my Sprint they stapled the floor down to the stringers and those staples eventually rusted and let water down into the stringers, and into the rest of the foam too (they missed the stringers with the staples on many many staples, so when rusted, those are just holes down into the foam).

[Gone Fishin']

Saw a pic years ago where a guy used plastic quart oil bottles all put neatly in his before he reinstalled the floor. Should certainly float and last a long while.

I have always thought that plastic bottles would do good for flotation. Not the crushable water bottles. More of the heavier duty ones like with gatorade, powerade, etc. They are usually built stout and a little hard to puncture. I would think if you were to glue the lids on tight and stack them into areas as tightly as possible that it would work good.

It would take a long time for them to probably degrade, they should hold air perfectly and there is nothing for the water to soak into. I should just run between them and out the area. Only thing I could think of is the possibility of expansion and contraction in hot/cold weather. Might affect the bottle some or the area if packed too tightly causing some distortion. Or could rattle around some if not packed somewhat tight. But for aluminum boats I think this would be acceptable.

Now I have not tried it or currently know anyone that has, but in theory it should work great.