Donzi F-21 Fuel Tank Replacement

[chris Farrington]

I have a 1990 F-21 and started getting water in the fuel. I pressurized the fuel tank with air and located the leak somewhere forward of the fill and vent fittings. I then proceeded to cut the deck and remove the tank which was badly corroded on the top. I also found lots of water settled in pockets of the flotation. There is a sealed compartment immediately aft of the tank that was half filled with water as well. Has anyone ever replaced a tank before in the F-21 and do you have any suggestions?

Chris Farrington.

[Tidbart]

Chris,

Welcome aboard. There are plenty here who have replaced their tanks and they will chime in. Also, do a search in the performance section for tank removal. You should find plenty of threads and lots of photos and information.

I, on the other hand, have a special request for you. Can you get the information off the tag on the old tank. I would like manufacturer, model, gallons, etc., anything you can find. If you really feel motivated, make a measured drawing of the tank dimensions. I am trying to keep some kind of database on tanks as I have a "special" fuel sender for classics. Any information you can get would really be appreciated.

Best of luck with you F21.

Bob

[chris Farrington]

Hello Bob,
Thanks for the info. The tag on the tank has the following information.

Manufacturer: Buechler Industries, Inc.
Model # 150-BI-85
Date: 06-90
Cap. Gals. : 85
Gauge .125 thickness
Alloy .5o52 Aluminum
Lot # 3 26

I am still cutting away at the foam insulation so I will have to send a sketch of the tank when I get it out. Hope I can pull it in one piece.

Chris.

[Tidbart]

Chris,
Thanks for the info.

Here is a tip from MOP about pulling the tank....


"The post below is for those pulling tanks that will come out unobstructed!

I did not read any of the other posts, cutting the tank is very dangerous. I was a boat mech for over 30 years and changed quite a few foamed in tanks, I never risked cutting one my life is mine to keep!!!!!!!! Use a long blade to cut the foam around the tank, then remove the sending unit. Get a steel bar about a foot long, take 1/2" line and make three loops around the bar this will give you a good attaching point to hook a "Come Along" to find a good over head place to hook to and crank it up, about the time the boat starts to lift the tank will come loose!

A P.S. put the bar long ways not across the tank, as you pull up the tank top will bow pulling the walls away from the stringers!!!

Phil"

Bob

[mrfixxall]

I am still cutting away at the foam insulation so I will have to send a sketch of the tank when I get it out. Hope I can pull it in one piece



use a chain saw,,,it really works,,paint a depth mark on the chain saws bar and go to town..

[chris Farrington]

Hello Bob,
Got the tank out, thanks for the tip with the come-along, it worked perfect, the tank popped right out! I have located a sketch of the tank from a reliable source, see attached file. Would you recommend replacing the tank with a metal or go with a molded plastic such as a Moeller or similar? I really never use the full 85 gallons with the original tank so I was wondering if it would be more practical and less weight if I were to install say a 50 gallon tank instead. What are your thoughts?
Chris.

[chris Farrington]

Hey Bob,
Here are a few pictures of my "work in progress"
Chris.

[Cuda]

Chris,
Thanks for the info.

Here is a tip from MOP about pulling the tank....


"The post below is for those pulling tanks that will come out unobstructed!

I did not read any of the other posts, cutting the tank is very dangerous. I was a boat mech for over 30 years and changed quite a few foamed in tanks, I never risked cutting one my life is mine to keep!!!!!!!! Use a long blade to cut the foam around the tank, then remove the sending unit. Get a steel bar about a foot long, take 1/2" line and make three loops around the bar this will give you a good attaching point to hook a "Come Along" to find a good over head place to hook to and crank it up, about the time the boat starts to lift the tank will come loose!

A P.S. put the bar long ways not across the tank, as you pull up the tank top will bow pulling the walls away from the stringers!!!

Phil"

Bob
You can fill a fuel tank with water to blow out any gas fumes. I knew a guy in high school who was welding on a fuel tank when it blew up. He was burned and scarred for life.

[Tidbart]

Good job on the removal, Chris.

Thanks for the drawing. FYI, It appears that Beuchler became, some how, AFP, which is now RDS Aluminum out of Perry, FL. So, if you go with aluminum, they are still an option. On the other hand, you have a drawing, so you can take that anywhere.

As far as plastic goes, you can call Moeller and see if there is a tank similar to yours or one that will fit in the compartment. They have a lot of semi-V tanks already designed. The problem would be getting the fills, vents, senders, etc in the correct locations. Cost would also be a large concern, if they had to make something custom.

My guess is that alum. would be the way to go. Being just a rectangular tank, I would imagine it is a fairly simple tank to make. Also, things have changed since your boat was made, as far as mounting. The preferred method is not to use foam anymore, but straps with neoprene. Also, if you go with alum., I would paint it. There have been some good suggestions as to what types of paint to use, but I don't know that info off the top of my head. Someone more knowledgeable will jump in eventually. If done right, an alum should last 30+ years.

As far as size, I would think keeping the length the same would be a good idea. This would keep the access points under the inspection plates. You may be able to narrow the width and depth, but you may need to beef up the stringers and underneath support to make up the difference. Once again, others know better on this subject as I have never had the fortune to replace one.

Just one last thought, you may be able to move this thread to the Performance section. I think there is a way to do this. If you can move it, there may be many more who will jump in with there .02 worth. I will warn you, sometimes it can be overwhelming.:bonk::yes:

Bob

If you keep with the rectangular style as opposed to a semi-V, I can get you a centroid style sender pretty cheap, no special programming on a rectangular tank. They have no moving parts, unlike the float style. If you decide to go this route, have the tank guys leave out the sender on a new tank. They usually put the cheapest ones they can find, from what I have seen.

[chris Farrington]

Hey Bob,
Could not figure out how to move this thread to the Donzi Performance section, perhaps someone could chime in and tell me how. Found the exact metal replacement tank at RDS in Florida, and another in North Carolina. Price difference between the two was about $300.00 so you have to shop around. I could not find a match with a molded plastic, so aluminum it is. See attached photos of the continuing "work in progress"
Chris.
P.S. I might take you up on that sender when I know for sure which tank I will be using.

[gcarter]

And the NC mfgr is Florida Marine Tanks, right?

I have another option for you since it's so rectangular and wide.
Surplus Unlimited in Daytona has a LOT of poly tanks in similar sizes to what you showed.
Normally these aren't useful in most Donzi classics due to the shape of the hull.
Surplus Unlimited has a web site;
http://www.surplusunlimited.com
Their site is pretty generic and doesn't really relate to what they stock.
Give them a call.
Since you're in Florida and Bahamas, you might want to by and see them.

[gcarter]

If you go w/aluminum, sand and Scotchbrite it to shiny metal, immediately primer it w/a good grade of automotive epoxy primer and coal tar epoxy.
I've done a few of these, here's a thread of one of them;
http://www.donzi.net/forums/showthread.php?t=49388