New fuel tank vs. Clean the old tank

[dave davis]

Hi Skippers,
This is an option that you might concider. There has been lots of information about how you should clean the old fuel tank and how difficult it is to do a through job. My c34 is 19 years young and it was doing just great until two weeks ago when I took a look in the bilge,which I do every time I visit Wind Dragon. I found it looking horrible with a 1-2 inch layer of RED fuel that looked like blood. Yes, it smelled like fuel and it certainly was red diesel.
I figure there are 706 boats out there that are as old or older than # 707 Wind Dragon. I motered it over to to the SF Boatworks where they pumped the bilge and tank and pulled out the tank. We found two corrosion holes in the bottom of the tank. We pressurized the tank with low pressure air and bubble tested the the rest of the tank. The welds looked good.
These old original tanks are made out of Aluminum alloy# 50-52 which is a good weldable alloy. I do not know if it is the best alloy for diesel, but it is made out of .062 which is, in my opinion rather thin. The new tanks are twice the thickness .125 in. The new tanks come with all the ready to go fitting and a new sender. They do not come with new hoses which is a good addition at the replacement time.
The cost of the tank from CY is $475 plus tax and ship. CY part # is 20791 These new tanks have not been painted which concerns me but shoud last at least 20 or more years.
Now, you can make your choice, CLEAN VS. REPLACE
Good Luck,
Dave

[Steve Hansen]

Dave,

So true, just after we purchased "Georgia Peach" 3 years ago my tank developed "pin holes" and had a slow leak into the bilge and also soaked into the port bulkhead in the aft state room. What a stinking mess. Those old tanks were thin and If I had it to do over, and being unfamiliar with the boats history, I would replace it. with all the hassle of scrubbing into every nook and cranny, and having to replace the bulkhead and working to get rid of every last bit of diesel stink, it would have been well worth the $225 cost to replace it.

Steve

[Ron Hill]

Guys : Dave's got a good point.  It might be well worth investing in a new tank!!
Where do the pinholes come from?  The water from condensation and in fuel taken on is the medium that the algae/critters grow in.  When they die naturally or bioside they mix with the water and form a acid that tends to eat/dissolve thru the aluminum tank.
One of the many solutions is adding water absorber and the new Starbright enzyme additive to your fuel. 
A few thoughts.   

[Mike and Joanne Stimmler]

Are the new tanks available in aluminum? I was told by a friend that they were only available in plastic.

[Stu Jackson]

Mike, from Dave's post it appears that they are the same aluminum, but twice as thick.  Best bet is to call the factory to confirm, or Dave will chime in here.

[dave davis]

The replacement fuel tank for a 1988 boat that I just bought and arrived Monday was made out of Aluminum Alloy 50-52. What they are putting on new boat is unknown to me. You might give Jerry Douglas at CY a call to answer your question. I bought my new tank from the CY parts department. Jerry designs new boats.
Good Luck,
Dave

[Ron Hill]

Mike : A few years back the Catalina factory offered the C34 fuel tanks in both plastic and aluminum.

I've heard the plastic tanks soon became permeated with diesel smell and the factory went back to Aluminum only.

[Jack Hutteball]

Ron is correct on Catalina offering a plastic tank, I have one in my 2001 MK ll.  So far no diesel smell from the tank in six years.  Here is hoping it does not.  On another note, I had an alumunum tank on our previous 27 foot sailboat for 25 years with nary a leak.  I guess there are optiions.
Jack

[tonywright]

The tank on my 2003 is plastic. Ditto no smell problem.  A plus you can see the fuel level independent of the gauge (if you open up the compartment). (Note: after 10 hours of running the engine, the tank gauge still reads full, but I am guessing that it should read about 2/3 - 3/4).

Tony

[Ken Juul]

Not sure of the shape of the plastic tanks, but the aluminum ones are narrower at the bottom than at the top.  Because of the added volume at the top, it takes longer for the float to move.  That last quarter sure goes fast!

[Roc]

I have a 2000 model since new.  First couple years, I found no odor problems.  Then as time went by, I noticed a strong diesel smell in the aft cabin, getting stronger every year.  I took the panel off many times to check for leaks, but found none.  I basically concluded that the poly tank has become saturated with the fuel, since the walls of the tank reek of diesel.  Also, in the beginning, the level of the fuel was clearly evident.  Now, the tank is opaque pinkish/brown.  Can't see a thing through it.  Fuel in the Racor bowl has always been a crystal clear pink.  Planning on swaping out with an aluminum tank.

[Martin1951]

Problem regarding water seperator b/w fuel tank and fuel pump. After running engine in moderate seas, about an hour or two, we are getting an air gap in bowl. The last time , it was only 1/2 full of fuel!! I've tightened the two radiator clamps at the tank and inlet connections , but still the same thing. My next idea is to swap out fuel line. Any other suggestions. has this happened to anyone else. Pleas e-mail us at-  Homeport220@comcast.net. Don't always have time to check threads.   Thanks marty & Lil

[Ted Pounds]

Is the gasket on the filter properly seated?  How about the O-ring on the bowl?  Just a couple o thoughts....

[Ron Hill]

Marty : You didn't say which kind of fuel filter you have as most 1986s didn't come with a Racor!! 

[crieders]

On a collateral note, my fuel gauage is hopping from full to empty. Is that a problem at the guage or in the tank? Thanks