Fuel Tanks ('66 flatback diver rebuild)

[Bhard]

Hey guys.  I'm having a heck of a time finding a decent size tank to fit under the deck of the boat.  

What size tanks (capacity and dimensions) have you used?

[LilRichard]

I bought a custom made aluminum tank, 63 gals.

You will most likely not find a pre-built that will fit under the deck, because the dimensions are very tight.

[71flatback]

Tempo makes a 36 gallon plastic tank that fit under my floor, but yours looks lower. It's  68 3/4" x 16"x 8 1/4"

[Bhard]

Still working on the tank issue.  It will definitely need to be a custom tank; I'm really trying to get a 40 gal one in there, but it looks like the tank will need to be about 7' in length to accomplish this. That seems long to me....  What do you guys think?    The boat's original stringers started tall in the front and slowly shortened as they went aft, because of the "flatback".  Even if we raise the floor an inch, the deepest tank we could probably go is 6.5".  I'm starting to wonder if it's worth it, but most importantly, I want to make sure that we're not compromising the strength of the hull by making that big of a coffin for a skinny tank.      Any feedback?

[Mad Dog]

Try these guys, http://www.speedytanks.com/

Built to your specs and ready to install when they arrive.  

MD  

[LilRichard]

I have your exact hull, and fit 63 gallons under the deck.  How far apart are you putting your stringers?  As I recall (these are only from memory, I can look up actual dimensions) my tank was something like 60" long by 30 or 32" wide by 7" deep.  I had them put a VERY slight vee in my tank.  The builder advised it would allow the pickup to access more fuel than a completely flat tank.  I think the middle is 1" deeper than the sides... resulting in less unusable volume.

You need at least 40 gallons on that boat, IMHO.   I would want to be able to run at least 4 hours.  You will have anywhere from 10-20% of the tank that is unusable.  40gals X 80% = 32gals.  Assuming you are running a four stroke that burns 8 gals/hr, that means 4 hours run time.

[Bhard]

Thanks for everyone's input!  It's great having a clean slate to work on, so I told Brien to go ahead with the stringers and we ended up with more width between the stringers than originally anticipated.  So we'll be able to shorten the tank and still get at least a 40 gallon tank in there.  Again, thanks.