"Do It Yourself" Boat and Canoe ideas

[reubenpa]

I was just thinkin the same thing!!  good ideas!!  maybe fill all the pipe with foam??? 

[Liar]

   How would you determine your max. capacity?  This is getting interesting.

[rgfixit]

Boat Building Physics 101

Archimedes' Principle:

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The buoyant force on an object is equal to the weight of the fluid displaced by the object.

An object floats when it displaces a volume of fluid whose weight is greater than or equal to it's own.

Filling the pipe (an already sealed vessel)  with foam only adds to the weight of the pipe producing a negative effect.

To calculate the displacement necessary to float an object you must;
-determine the total weight of the object
-divide the weight of the object by 8.34 ( weight of 1 gallon of water)
-multiply the total water to be displaced by 231 (1 gallon = 231 cubic inches)
The resulting figure is the amount of displacment necessary

Example;
Your float, with you and your gear will weigh about 350 lbs maximum.
350 / 8.34 = 41.97 gallons
41.97 x 231 = 9695.07 cu. ins.

A piece of 12" I.D. pvc pipe has a volume of  1357.2 cu. ins
1357.2  / 231 = 5.88 gallons of displacement per lineal foot of pipe

41.97 gals. / 5.88 = 7.14 ft of 12"pvc to float 350 lbs

Confused???

RG

[crappieloo]

Then how ''small'' can the vessel be if you install schrader valves on the floats, evacuate all the air down to 30'' let it set 1/2 hour to make sure that theres no leaks then fill the floats with helium?

[rgfixit]

Lou...you're killin me

I have no idea

RG

[crappieloo]

I just thought you might want the float boat a few pounds lighter. It will work, because we had a full tank of helium that we didnt want to return till we got are monies worth and had a riot sending stuff up in the air.
We havent laughed so hard in years, especially when the wind carried the ''stuff'' over a restarurant on a warm summer dinner time. Those outdoor patio patrons sure had a eyefull when they saw a bunch of crap floating by. I cant type anymore cause im in tears laughing so hard

[rgfixit]

The problem with helium is that it needs to expand into a large, lightweight vessel. It needs VOLUME.

If it worked in compressed states, your tank would simply float away
RG

[crappieloo]

Yeah i know that. What i meant was let the vacuumed vessels(pvc tanks) suck in the gas until the volume was filled to equill atmospherice presure. Wouldnt gain (i mean loose) that much anyway.
Guess it would be easier to get a store bought float boat anyway.

[grumpymoe]

guys....sorry to take you away from your hindenburg thoughts...the coolest thing i ever saw was a number of years ago while fishing a southern manitoba river that had some shallow rapids.. one....two...then the third came by... kayak paddles and homemade indestructable boats made from truck/car hoods.. i think they were from late 40's ford and chevy truck hoods...you know...the deep tapered hoods..what they did was take two and cut straight edges and welded them together and then for a seat and buoyancy, they used a fuel tank secured across the welded section...those boats were sooo neat... and watching this discussion progress to helium reminded me of this long forgotten day....grump

[Bigfish57]

hehe thats awesome

[rgfixit]

I was fishing the Cohocton River a few years back...Way off the beaten path when a couple of kids came floating through in inner tubes...then a few more in 55 gallon plastic drums cut in half...then a bunch more in every kind of home made thing that would float.

 Turned out to be scout troop's "Anything That Floats" trip. Man they were having fun 

RG

[reubenpa]

Get me a BIg wheelbarrow and put liquid nail over the holes and jump in!!!!  lolJK

[kerosenecounty17]

RG - thanks man.  Archimedes.  That's the dead guy I was trying to think of.  Question for you though.  Using your pontoon, a 1' x 7'-2" pontoon (or actually two 3'-7" pontoons) would just float 350# correct?  The pontoons would actually be completely submerged, and you'd have a 12" draft and a wet rear end, correct?  If you used a pair of 7'-2" pontoons you'd have about a 6" draft, right?  Man, it's been a long time since advanced physics. 

kero

[rgfixit]

Kero, That calculation would be for level floatation. Were it me, I would calculate based on maybe 550 lbs or so.
RG

[crappieman12887]

Hey, I didn't get a chance to take pics last night.  Will do it this weekend.  I have taken my 16' canoe out by myself.  It works if you use a five-gallon pail full of rocks or something to put in the bow for ballast.  Otherwise, you will have to sit in the center of the boat.

I have tried it with just me in the back and no additional weight and it is really hard to control the canoe in even the slightest wind.  Not to mention you lose a lot of freeboard in the stern!

try using a couple of sand bags they sit much flatter in the bow and work really good.bill