Fuel Tank Size

[Rootsy]

I need to buy a fuel tank for the 18... i have a couple of options.. a stock replacement @ 23 gallons.. or a custom sized tank at 34 gallons... not sure if it is worth it or not.. i have to put a new bulkhead in anyway.... so see the pole above...

[Lenny]

Go big Jamie. It is hard to go on any decent "Poker Runs" with the 25G one I have. Just ask Mike :rolleyes:

Go for 40 or so if you can. Move it back too, if that is at all possible with the ski locker there.

[BERTRAM BOY]

You should cut out the back seat and strap in a 275 gal home heating fuel oil tank. That will solve your problem......

[Patti]

Cliff!
Don't give him any ideas :tongue: :jestera:

[boatnut]

Some thoughts:
1) If you get challenged to a race right after filling the tank you are going to lose X MPH with the extra 70 lbs or so of fuel if you go with the 34 gal tank.
(we can debate how small X is, but it is a positive number :) )
2) I do realize the challenges of a 23 G tank as I have owned an 18 classic since 1970 and have used a rope to push several boats into the fuel dock -- once the push was almost 20 miles -- embarassing.
3) If you buy fuel where you buy beer you will be motivated to fill up in a timely manner.
Are you mounting the new tank in foam? Or? You said you had to redo the bulkhead anyway -- why? Good Luck with the decision and the poll.
Ed

[penbroke]

There is no point in putting a 23 gallon tank in that boat with all the other work you are doing. Especially with what I expect will be under the hatch. :biggrin:
Do you still have the tank drawing I sent you? After putting that tank in my boat I think you could strech the size even a bit more. The 34 gal. tank I put in mine lets me run where ever I want with no worrys. Your milage may vary...


Frank
Now offically a 12 month Vermont boater.

[MOP]

Jamie I have 36 usable out of my 40 gal tank in the 22, it is sucking through a little on the rich side 750 feeding the 383. At 1k last year I ran 103 miles and ran out due to gauge being wat off, I am pushing about 6-700 lbs more boat. Hope that helps with your thoughts!

Phil

[Rootsy]

Some thoughts:
1) If you get challenged to a race right after filling the tank you are going to lose X MPH with the extra 70 lbs or so of fuel if you go with the 34 gal tank.
(we can debate how small X is, but it is a positive number :) )
2) I do realize the challenges of a 23 G tank as I have owned an 18 classic since 1970 and have used a rope to push several boats into the fuel dock -- once the push was almost 20 miles -- embarassing.
3) If you buy fuel where you buy beer you will be motivated to fill up in a timely manner.
Are you mounting the new tank in foam? Or? You said you had to redo the bulkhead anyway -- why? Good Luck with the decision and the poll.
Ed

have you not seen the saga of the "red mistress"??? bulkhead was pretty much removed by the owner before the previous owner to cram some pos weirdo tank in there... foam or not to foam.. we'll cross that bridge when we get there but ummm i am pretty much anti-foam... i am investigating what is available in modern materials for foams though...

Penbroke,

i have your drawing but some of the dimensions are difficult to decipher.. is that 43 or 48 OAL??? i think i have the rest... the 365 dollar 33.7 gallon quote from Florida Marine Tanks is using your drawing and a 48 inch length... therefore i'd put 50 inches between bulkheads and that should be just shy of the opening for the center cooler so i can still put the tub in there... if i ever get it back or make a new one... I did measure the top of the stringers to the base of them and the keel tonight at 0, 12, 24, 36 and 48 inches (1 inch clearance between bulkheads) tonight... don't quite match what you gave me.. donno how the tank you spec'd will fit.. i don't think it will but i need to look at the print again.

thanks for the moral support ;)

[Lenny]

You know Jamie, you could go the Kevlar route and use a fuel cell, like Geoo did. :) No foam to muss with, no deteriation.

http://www.rdsaluminum.com/pages/1/index.htm

http://www.donzi.net/forums/showthread.php?t=33132&highlight=fuel+tank

http://www.fuelsafe.com/pdf/Marine.pdf

[New2Donzi]

I purchased one from RDS for my project.
I did not realize the orginal size was 23 gallon or I would have opped for that.
I will be using the boat on a river at the cottage and do not require the extra capacity. Does anyone have the drawing for the 23 gallon as I may order one of those instead. I don't know what I'll do with the 41 gallon though.
Cheers...Ed

[boatnut]

You know Jamie, you could go the Kevlar route and use a fuel cell, like Geoo did. :) No foam to muss with, no deteriation.


Does anyone have a ballpark price of a fuel bladder made to fit the space available on the old 18's? It could be considerably more than an aluminum tank and still be justified by reduced installation time/labor/cost, elimination of corrosion and breakage issues, and probably significantly more capacity as more of the space could be used by the tank/cell. Possibly a better price could be achieved if we did a multiple custom cell buy?? I would be interested depending on price. Another source is http://www.atlinc.com/marine.htm
Ed

[MOP]

Bladders are very expensive, if you check back through Geo´s old posts you will see he had a weepage problem. Jamie I guess I would be anti foam as well being as it only lasts about 30 years, but you may want to some give thought to the well proven structural integrity it adds to the boat and if done with modern coatings it may last 50-60 years. I have a hunch you will sell it before that!

Phil

[boatnut]

Bladders are very expensive, if you check back through Geo´s old posts you will see he had a weepage problem. Jamie I guess I would be anti foam as well being as it only lasts about 30 years, but you may want to some give thought to the well proven structural integrity it adds to the boat and if done with modern coatings it may last 50-60 years. I have a hunch you will sell it before that!
Phil

Phil, I hear you and being I am 64 yrs old, 30 years seems long enough for a part to last. However in this case I don't think it is. I have older boats that I maintain and the tanks are not an issue because they are inspectable and replaceable. When the tank is buried, unaccesable and replacement requires major surgery on the boat it should last as long as the hull lasts -- otherwise after we sell the boat some unsuspecting family may own the "old" boat that is on its third engine after the restoration and it may go boom. I do believe the way George coated and foamed in his tank is a responsible way to do it--but foaming metal into a bilge is risky. I also don't think this boat design needs any additional structural support where the tank is -- the angle of the vee in this area and the stringers and the bulkheads are structurally rigid enough. If a fuel cell cost $10,000 it wouldn't be worth it, if it cost $1,000 it may be the best investment in the restoration. There is a reason many of the offshore race boats use this technology -- not that they have a tight budget of course. Ed

[gcarter]

Does anyone have a ballpark price of a fuel bladder made to fit the space available on the old 18's? It could be considerably more than an aluminum tank and still be justified by reduced installation time/labor/cost, elimination of corrosion and breakage issues, and probably significantly more capacity as more of the space could be used by the tank/cell. Possibly a better price could be achieved if we did a multiple custom cell buy?? I would be interested depending on price. Another source is http://www.atlinc.com/marine.htm
Ed
Ed, I'm not sure you would have many people lining up at $1600-$1800.00 each. I thought about it, but agree w/Mop, how long do you want it to last?
Just buy some of my coal tar epoxy.

[boatnut]

Ed, I'm not sure you would have many people lining up at $1600-$1800.00 each. I thought about it, but agree w/Mop, how long do you want it to last?
Just buy some of my coal tar epoxy.

That is a very possible plan of attack, even though I don't like the concept of foaming the metal into that area. Of course we do not have any data on what will happen to fuel cells over long time periods either although I haven't talked to any of the sources of this technology. I think properly constructed a built in fiberglass (epoxy) tank would work there also, I have seen them last for over 30 years. However, I am not knowledgable enough to do it myself.
The success of any of these solutions is determined by the attention to detail of the installer as well as the design of the process---that is why some of the Donzi tanks seem to last and not leak and others fail (in my opinion).

[Lenny]

I believe they start at $800-ish

[penbroke]

Penbroke,
i have your drawing but some of the dimensions are difficult to decipher.. is that 43 or 48 OAL??? i think i have the rest... the 365 dollar 33.7 gallon quote from Florida Marine Tanks is using your drawing and a 48 inch length... therefore i'd put 50 inches between bulkheads and that should be just shy of the opening for the center cooler so i can still put the tub in there... if i ever get it back or make a new one... I did measure the top of the stringers to the base of them and the keel tonight at 0, 12, 24, 36 and 48 inches (1 inch clearance between bulkheads) tonight... don't quite match what you gave me.. donno how the tank you spec'd will fit.. i don't think it will but i need to look at the print again.
thanks for the moral support ;)
My tank is 48" long. You should be able to pull any dimensions you need from the DWG file I sent you. As I recall I could have gone 50" long and still cleared the storage well. That should add a couple more gallons or so.

To come up with the dimensions I made a cardboard template for each end of the tank and connected the corners. I left 1" all around. This tank fits just fine in MY boat. I'm not sure how much the same the boats are?? I suspect the bulkhead at the front of the tank compartment may move around a bit from boat to boat. You MAY find you need a flat on the bottom of the tank to accomodate the pvc tube that drains the compartment in front of the tank.

PM me if you want to talk about it...
Frank

[harbormaster]

I had about 40 gallon capacity in my 1995 18 classic. It was great. I could run all over the place without having to refill at the high priced dockside gas pumps(which is what you would have to do when you run low with your itty bitty tank. The difference in cost of the gas at a car pump and dockside is enough to pay the difference in tanks.

[JimG]

If I had trim or tabs, I'd go bigger. I do not have either. A full tank really effects my ride in rough water, so if it were my boat I'd go 23 gallon.

Jim

[Lenny]

Jamie, why not put some wax paper in the cavity, pour in some A/B foam, let it go off, saw it flush to the top of the stringers, and disect that for volume and such and shape. Maybe draw it up for a fuel cell quotation. ? ? ?

[Rootsy]

Jamie, why not put some wax paper in the cavity, pour in some A/B foam, let it go off, saw it flush to the top of the stringers, and disect that for volume and such and shape. Maybe draw it up for a fuel cell quotation. ? ? ?

already had a quote for penbroke's tank which he put in his 18 triple hatch... measured my hulll and stringers over the span of the tank... made a solid model of it today... 35 gallons... essentially the same as penbrokes within an inch or so at the aft...

we'll go this route... no issues...

[penbroke]

Hey Rootsy, you up?? You have mail...

Frank

[Rootsy]

here's what is gonna get ordered... i am having RDS quote this tank and it is very similar in dimension to penbroke's drawing... This tank is derived from 1 inch clearance fore and aft, 1 1/2 inches below top of stringer.

[penbroke]

My tank actually came through with a 1-1/2" O.D. barb fitting for the fill even though I spec'd the 1-5/8". I had to turn down the O.D. of the nipple on my deck fitting for the 1-1/2" fill hose. No big deal but the devil is in the details. I just remembered that little thing... :banghead:

Also the epoxy primer they (RDS) use is not so bad...


Frank

[Rootsy]

sent the print, quotation and check to FMT Monday afternoon... 365 + shipping for the tank in the attachment above... 34 net gallons... modified it to use a 1/2 inch pickup and 1/2 NPT... just in case i decide to get froggy in the future and need more fuel delivery capacity ;)

delivery is 3 - 4 weeks from receipt of payment...

FYI, RDS quoted this tank at almost 500 dollars, stating that it is a "difficult" tank to manufacture... they didn't take too kindly when i asked them to defend their quotation... too bad... i do it to suppliers every day.. they are no exception...

JR

[gcarter]

Good for you Jamie. Looks to me like a good price.

[penbroke]

:D

Frank

[GEOO]

My Air Craft Rubber 62 gal tank, approx 24" x 72" cost $ 1,600.00 in 2003.
Bladders don't last forever but are easy to change. Life is 5-8 (+-)years. You won't crack a weld like an alum tank but the fabric the tanks are made of does leach some fuel smell, much like a plastic tank would. The fabric life is shorten if it sits in water.

[Rootsy]

Since someone brought this back to the forefront by voting... i figured i'd tell you all which one won... 34 gallons.. built to my blueprint... by Florida Marine Tanks... 475 delivered (that included the 110 in UPS COD charges)... it's already installed in the hull :)

[staarrl]

Rootsy,

Any chance you'd share that drawing with a new owner of a 1967 18" triple hatch with a leaky 24 gallon tank? If I'm going to take the top off to put in the tank may as well make it bigger. Cousin's got an 18 with a 400 hp monster and still the 24 gallon tank and can't stay out too long!!

Thanks, Bob

:canada:

[Carl C]

So who's the wiseguy who voted on a 5 year old obsolete poll? :hangum:

[Wet Vette]

I'm replacing the tank(for the 2nd. time) in my 1972 18' 2 + 3 and would like to ask a few questions.

Did you go with the 34 Gal tank?

where did you buy it from?

Does the storage locker fit with a 34 gal tank ?