15 foot 1981 eldocraft flat bottom (new floatation apporach)

[magictom]

Hello All,
My son and I have been remodeling a boat we bought online.. stripped it down completely and began rebuilding it. After having to remove 400 lbs of waterlogged foam from the hull (with a saw and crowbar) we decided to go with an alternate floatation process.. We chose to recycle plastic water bottles and fill the hull with them. Over all it will take about 500 bottles. Since these are advertized to be "in a land fill forever" we figure they will hold up under the floor of our Jon and keep us afloat if the worst happens. This was free and easy (in coparison to replacing foam). Im not an engineer, but my assumption is that this many water bottles with caps sealed will keep the boat afloat if it gets swamped. AND IT WILL NEVER WATERLOG! If you ARE an Engineer, and can validate the weight that this many water bottles will keep afloat, that info would help tremendously.

We also picked up some camo painting tips on youtube and it worked like a charm. if you like the paint job, shoot me a note and I will share the method. PLease check out my Pics, I will continue to post them as we make progress on the boat.

This site has provided a wealth of info to us and we are glad to finally be able to contribute back!
Comments are appreciated!
Thanks
Tom

 

[Zum]

A cubic foot of air,will support around 62lbs.
Interesting idea,not sure how it will last and I don't know if it's legal.
If you know the volume of the bottles(cylinder)it will give you a good idea of how much weight it will support.
Rough guess..2 bottles about a foot long,2inches wide.
.083'x.083' x pie x 1'=approx.0218 x 62.4=1.36lbs x 250 approx.=340lbs.

Glad to see the family involved and welcome to the site.

 

[Quackrstackr]

The problem that you are going to have with those water bottles is that they are going to abrade and develop holes over time because they are not being held completely stationary. How long that takes depends on how much play that there is in them. The caps are also prone to splitting as they age, weather and see temperature extremes.

It will take 48 20oz water bottles to float 62 lbs.

 

[magictom]

Well,
Not sure how many bottles i need to add. will have to do a re-count.
I think I have about 500, per your calculations that will support up to 645 lbs.
I will need to weigh the boat in after the remodel and verify the weight to see how close I am.
i can lift one end prettt easily now but probably not once it has all the decking in it.

That was a HUGE help! Thanks a million!

In regards to the legalities of the flotation type, I understand that boat manufacturers have to meet flotation code in new boats under certain lenths.. but I also understand that once it is purchased, the owner can remove the floatation as desired. Is this incorrect?
Please let me know. We are putting a lot of work into this baby, I want to make it legal.

As it stands, the bottles take up more space than is available, when I install the aluminum floor and rivit it to the crossmembers, the bottles will be compressed and will not have any movement, they will never be exposed to UV rays as they are under the floor.
Not sure how they will react to hot and cold variations in the weather. Guess I will find out!
Maybe taking the floor off after a year and inspecting them will be the safest way to go.

 

[Deckerd]

A cubic foot of air,will support around 62lbs.
Interesting idea,not sure how it will last and I don't know if it's legal.
If you know the volume of the bottles(cylinder)it will give you a good idea of how much weight it will support.
Rough guess..2 bottles about a foot long,2inches wide.
.083'x.083' x pie x 1'=approx.0218 x 62.4=1.36lbs x 250 approx.=340lbs.

Glad to see the family involved and welcome to the site.

Why don't you just fill 10 bottles with water and weigh them? Then count ALL the bottles and do the math. It would help to know your boat's gross weight. Hope they don't rattle around too much. Really nice boat, though. Lots of potential.
Deckerd