Floating A Fishing Platform With 250 Gal. Propane Tanks - Building & Construction - DIY Chatroom Home Improvement Forum

 DIY Chatroom Home Improvement Forum floating a fishing platform with 250 gal. propane tanks
 Register Blogs Articles Rewards Search Today's Posts Mark Forums Read

01-31-2009, 04:41 AM   #1
Fishermen

Join Date: Jan 2009
Location: Texas
Posts: 2
Rewards Points: 10

## floating a fishing platform with 250 gal. propane tanks

Im building a fishing platform that is 21ft. long and 12ft. wide with 7ft elevated deck on it. I have access to 250 gal. propane tanks. So my question is how many will it take to float 10,000 lbs. If anyone can help me calculate how many it will take i would sure appreciate it!

01-31-2009, 09:38 AM   #2
Member

Join Date: Mar 2006
Location: Austin, TX
Posts: 1,599
Rewards Points: 1,220

You need to calculate the weight of the deck first. Then take the weight of the 250 gallon tank and subtact 2000# from it. That negative number is the approximate amount of flotation provided by each tank.

__________________
Advice is free, Lessons begin at 75 bucks an hour.

 01-31-2009, 10:07 AM #3 Master General ReEngineer     Join Date: Dec 2007 Location: Chaumont River, Ny. Posts: 6,025 Rewards Points: 354 Ayuh,... Each Gallon of displaced water will float about 8lbs..... Personally,.... I'd use 55gal. Plastic Drums,+ stuff as Many as Possible under it..... The Plastic Drums weigh less than steel tanks, Don't Rust,+ are much Cheaper.... By using More floation than is absolutely Necessary, insures that it don't Sink when some of the floation is compromised... Which Will Happen,... Eventually..... Last edited by Bondo; 01-31-2009 at 05:30 PM. Reason: Editted to reflect the brain fart
 01-31-2009, 05:15 PM #4 Member   Join Date: Jul 2008 Location: Canada (s/w ON.) Posts: 2,294 Rewards Points: 1,000 The weight of a US gallon of water is about 8.3 lbs. To support 10,000 lbs you will have to displace 10k/8.3=1205 gallons of water! For your tanks to float half way out of the water, use a total of 2400 US gallons in total tank volume!
 01-31-2009, 05:32 PM #5 Member   Join Date: Mar 2006 Location: Austin, TX Posts: 1,599 Rewards Points: 1,220 Doh! Double post. __________________ Advice is free, Lessons begin at 75 bucks an hour.
 01-31-2009, 05:32 PM #6 Member   Join Date: Mar 2006 Location: Austin, TX Posts: 1,599 Rewards Points: 1,220 Does US water weigh more than, say, Ethiopian water? __________________ Advice is free, Lessons begin at 75 bucks an hour.
 01-31-2009, 05:36 PM #7 Master General ReEngineer     Join Date: Dec 2007 Location: Chaumont River, Ny. Posts: 6,025 Rewards Points: 354 Ayuh,... You're Absolutely Right Wildie,... I edited my post to Fix it... I was thinking of Cubic Foot of course, which is about 60lbs buoyancy... 21ft. long and 12ft. wide That would be 6 runs of 7 barrels each,.... That's about 2300 gallons...
01-31-2009, 05:40 PM   #8
Master General ReEngineer

Join Date: Dec 2007
Location: Chaumont River, Ny.
Posts: 6,025
Rewards Points: 354

Quote:
 Does US water weigh more than, say, Ethiopian water?
But,..
Did you know a Steel tank Full of Freshwater will Float in the Ocean,..??

 01-31-2009, 05:59 PM #9 Member     Join Date: Oct 2006 Location: Minneapolis/St. Paul, Minnesota - Latitude 45.057 Longitude -93.074 Posts: 4,040 Rewards Points: 2,570 Don't forget about the weight of the tanks, the weight of the people, the weight of the grill and charcoal and the fish they will catch. - At least 6 to 8 tanks unless you have inflated the deck weight.
 01-31-2009, 06:04 PM #10 Member   Join Date: Mar 2006 Location: Austin, TX Posts: 1,599 Rewards Points: 1,220 If it wouldn't, there would be no life on Earth as we know it. (It would depend upon the size and composition of the tank, technically). __________________ Advice is free, Lessons begin at 75 bucks an hour.
 01-31-2009, 07:10 PM #11 Whatamess   Join Date: Jun 2008 Location: Costa Rica Posts: 423 Rewards Points: 250 The weight of a gallon will depend on temp. if you really want to get technical about it.Ethiopian water would probably weigh less. __________________ I may go home hungry, but not tired and hungry.
 01-31-2009, 10:51 PM #12 Member     Join Date: Mar 2005 Location: Welland, Ontario Posts: 12,402 Rewards Points: 11,596 Blog Entries: 11 If the Ethiopians use imperial gallons instead of US gallons then the Ethiopian gallon will weigh 10 pounds, definitely more than US.
02-01-2009, 12:01 AM   #13
BJ

Join Date: Aug 2008
Location: Tampa
Posts: 83
Rewards Points: 75

## Fresh or salt water? Although there is no true fresh water

Freshwater, assuming it is relatively free of 'too many pollutants' (good luck finding any 'PURE WATER' - since greedy, moneygrubbing industries have polluted about all of it on the planet), is nearly always listed at 8.33 lbs. per gallon. However, according to my 'very accurate scales', a single (U.S.) gallon of 'freshwater' weighs-in at 8.44 lbs. per gallon.
Saltwater ('pure saltwater': meaning 'purified- freshwater' with a synthetic sea salt completely mixed to a specific gravity of 1.022 (again, the 'recommended' specific gravity measurement is another argument altogether). However, this mixture (at 76 degrees Fahrenheit) is much heavier than Freshwater, coming in at 11.2 lbs per gallon; which is (obviously) 1.54 lbs per-gallon heavier.
And...

There is 231-cubic inches in a standard U.S. gallon. Therefore, to find the volume of air in a Cylinder would go back to the fun of Algebra and V= tt (as close as I cold get to the symbol for pi 3.14) * R (radius) squared * the hight of the cylinder divided by 231 would give you the volume few the cylinder portion of the propane tanks in cubic feet.

One cubic foot of saltwater is approx. 7.5 U.S. gallons and 'true' weight is determined by the 'exact' salinity (and in a minuscule way, the temperature & water purity, as well...

You don't really want to know how to figure out the volume of the domed portion of the cylinders, do you?

Ethiopian water would be worse than “Don't drink the water” Mexican water so would weigh more than US water depending on the amount of contaminates dissolved in it.

As for water in the US, the water that comes out of a modern sewage refinery plant is better (lack of contaminates, etc.) than 98% of the tap water in the country.

Other than being manufactured by combining hydrogen and oxygen ie. the Space Shuttle launching minus the solid boosters there is no such thing as “fresh water”. All of it's gone through something, so we call it “Dino Pee.”

So, I'm the President and Technical Director of an environmental organization and figure out things like all of the fresh water entering Tampa Bay and have to allow for evaporation.

It ain't rocket science unless your building rockets!

 02-01-2009, 03:35 AM #14 Fishermen   Join Date: Jan 2009 Location: Texas Posts: 2 Rewards Points: 10 thanks guys i appreciate it, i was thinking 6 tanks which would give me 1500 gallons. i believe the deck will weigh with the tanks approximately around 7500lbs. which 6 tanks should float 12495lbs. so it will leave me with 4995lbs. to accomidate people, fish, gear, etc. By putting extra air in the tanks would that help float more? people have told me to fill them with foam. i think the sidewalls (5/16") of the tanks are rigid enough to withstand a impact from a small boat in the night or whatever kind of accident like that.
02-01-2009, 10:17 AM   #15
Master General ReEngineer

Join Date: Dec 2007
Location: Chaumont River, Ny.
Posts: 6,025
Rewards Points: 354

Quote:
 By putting extra air in the tanks would that help float more? people have told me to fill them with foam.
Ayuh,...

Neither idea will increase the bouyancy,...

Actually,... It'll add Weight,+ lower the bouyancy...

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are Off Pingbacks are Off Refbacks are Off Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post MrLinux Building & Construction 6 02-08-2008 12:00 AM Badfish740 General DIY Discussions 1 09-25-2007 08:46 PM

Top of Page | View New Posts