Leaking fuel tank-34 MT DC W/ 250 Cummins

[Reelalure]

We showed up to the boat today after its first cruise of the season last week and found diesel in the bilge. I think I found were the tank has been leaking for a long time but it was very minor and contained to an isolated spot under a floor board that the generator battery sits on. I don't know why so much fuel leaked now and it did not seam to leak any more last night or today. We are going to continue to watch it this week. Has anybody replaced the tanks on a 34 double cabin? How big of a job was it $$$? I would imagine the engine will have to come out, the engine room is very tight. Is there any way to repair a tank or put a liner in it?

 

[Anode]

So it only leaks when you're underway?

 

[Larry M]

We have not used this product but we know people who have and had great sucess. They ordered the CS3204-2B


http://www.flamemaster.com/Technicals PDF/CS3204 rev 01-07.pdf

 

[alormaria]

I had to have the tanks replaced back in '94. It cost around 8 boat units. The engine and trans were removed for the work.

 

[Forkliftt]

We showed up to the boat today after its first cruise of the season last week and found diesel in the bilge. I think I found were the tank has been leaking for a long time but it was very minor and contained to an isolated spot under a floor board that the generator battery sits on. I don't know why so much fuel leaked now and it did not seam to leak any more last night or today. We are going to continue to watch it this week. Has anybody replaced the tanks on a 34 double cabin? How big of a job was it $$$? I would imagine the engine will have to come out, the engine room is very tight. Is there any way to repair a tank or put a liner in it?

Larry offers a good idea. Keith on the forum had his tanks repaired successfully several years ago and has posted some great pictures of the process. You may want to consider that approach before having them replaced.

 

[Reelalure]

I assume it only leaks underway or only after the tank is warm. This weekend was the first time I have seen any leakage. It did not seem to leak on Friday or Saturday but we did not run the boat. I will check again on Tuesday and we are going to run it this weekend and monitor it. Thanks for the links I will check them out tonight.

 

[Jeanne]

We too awoke the other day to find fresh diesel in our bilge. We own a 78 Marine Trader and I think it's about time for this type of problem, and since we've been making repairs on everything else since purchasing the boat a year ago. What does 8 boat units mean? $8000? I assume. I will check out the link(s) above and any other suggestions you all may have. Thank you in advance.

 

[El Sea]

ETwo weeks ago a customer across the state calls and request a pumpout due to a leaky tank. We show up pumpout the two tanks and transfer the fuel into a boat in the next slip (whom had agreed to buy the fuel).
Job all complete, we get 40 miles down I-95 and are called back. The fellow that bought the fuel originally had a leak in his tank and thought he had completely sealed the leak.
We will be returning later to empty the 55 gallon barrels in his cockpit.
What is to be learned here is sometimes it is better to replace than repair.

 

[Aquabelle]

If it leaks while underway and/or when the fuel in it is warm, it will not be long before it leaks under ambient conditions...if it isn't doing so already. Get specialist advice, fast.

 

[SeaMoose]

From my experience repairing the tanks is a losing battle, you fix one leak, and another one appears. When I removed my tanks, the rust in the places I couldn't see was astounding. The gunk in the bottom of 30 year old tanks has to be seen to be believed.

You do not have to remove the engine at all. With a good recip saw and plenty of blades it takes about two days to cut them up and remove them.

I replaced mine with 4 25 gallon plastic tanks. 100 gallons at 2 gallons an hour is 40 hours of run time @ 6.5 knts with a good reserve, 260 nautical miles, I'll run out of water and food by then anyway. And there is so much space in the engine room, it is the envy of all of my powerboat friends.

While you're at it, replace the mechanical fuel pump with an electric one, with a few valves and manifolds you now have a poor mans fuel polishing system.

Around two and a half boat units including a new Racor filter, four fuel gauges, two custom fabricated manifolds, Apollo/Conbraco valves, and marine plywood impregnated with resin for the tank bases.

Alan Robbins
34' 1976 D/C "Sea Moose"

 

[Max Simmons]

Hey Moose, any pic of your installation? No problems yet on mine (knock on wood) but something I'm mentally preparing for in the future. I carry 300 gal in two tanks, which for my cruising is way overkill. I've been thinking that I'll do same as you.

 

[yo]

leaking fuel tanks

Sea Moose Allen I did the same as you, cut out the old 150 gallon tanks but I replaced with 4 tanks that hold 50 gallons each. Didn't remove the engine either. But I'm thinking of removing the two forward tanks and just going with the 100 gallons and using the extra space for something else. Do you still have the lift pump still in place and just run on the electric fuel pump or did you by pass it?
Mike

 

[Forkliftt]

Hey Moose, any pic of your installation? No problems yet on mine (knock on wood) but something I'm mentally preparing for in the future. I carry 300 gal in two tanks, which for my cruising is way overkill. I've been thinking that I'll do same as you.

450 worth of tankage here and I agree. Way overkill. With diesel's shorter tank life and Activecaptain to locate fuel, 100 gallons would be plenty for me.

 

[El Sea]

Plastic tanks would not be my first choice for diesel fuel. Primary reason, we see tons more contaminates in plastic tanks compared to aluminum tanks. Mainly due to the warm return being added thus the contaminates begin.

 

[Forkliftt]

Plastic tanks would not be my first choice for diesel fuel. Primary reason, we see tons more contaminates in plastic tanks compared to aluminum tanks. Mainly due to the warm return being added thus the contaminates begin.

El Sea, Can you describe the "perfect" 50 gallon diesel tank? Assuming you would install a matched set, one on each side where 4 larger tanks currently are? Aluminum? Tall? Short? Thanks

 

[psneeld]

Aluminum would be my last choice as long as the tanks are less than 100 gallons each.

I think...(under no real scientific reason other than if not baffled well...sloshing) I would prefer a tall vesus short tank.

I'm thinking of building my own fiberglass tanks, maybe 2 - 75 gallon tanks where they would conform to the bottom slope... something like 20 in x 30 in x 30 inch.

Building my own allows me to place the fill. vent, crossover, feed and sight glass ports where I want and not where some manufacturer wants based on production needs without the massive "custom" costs.

 

[El Sea]

We recently had to service two pairs of tanks that were stacked (absolutely not per my recommendations) two tanks on the port side and two on the stb'd.

My choice for replacement tanks would be vertical tanks, manifolded together and low point drains. I would prefer minimum volume (unless passage making is in the future) to manitain fuel quality and never-ever-ever use bio-cide. Bio-cides kill bugs and water is a breeding ground for bugs. Do away with the water and the bug disappears. Use the low-point drain to remove the water and never-ever-ever use bio-cide.

FWIW, Our boat has fiberglass tanks with bottom feed (one of the major reason we bought).

 

[psneeld]

We recently had to service two pairs of tanks that were stacked (absolutely not per my recommendations) two tanks on the port side and two on the stb'd.

My choice for replacement tanks would be vertical tanks, manifolded together and low point drains. I would prefer minimum volume (unless passage making is in the future) to manitain fuel quality and never-ever-ever use bio-cide. Bio-cides kill bugs and water is a breeding ground for bugs. Do away with the water and the bug disappears. Use the low-point drain to remove the water and never-ever-ever use bio-cide.

FWIW, Our boat has fiberglass tanks with bottom feed (one of the major reason we bought).

Can I steal an idea of how big and thick the walls are and baffle spacing????...

 

[yo]

leaking fuel tanks

One thing that I like about my plastic 50 gallon tanks, If I think that I have a bug problem or that I have picked up bad fuel. I use the electric pump and clean it with one of those big water filters. pump the fuel back into one of the empty tanks and when tank is empty I pull the tank out of the boat and clean the tank .
mike

 

[El Sea]

Talking with the tank fabricator we use here in St Petersburg last week regarding pricing and the wall thickness came up. For tanks less than 100 gallons the wall thickness is around 1/8" then over 100 gallons wall thickness is 1/4". From what we can estimate when sounding tanks and probing during cleaning is the ballfes are no more than two feet apart. When we cut tanks open, baffles are fab'd from the same outside material.

For pricing; up to 100 gallon tanks are $10.50 per gallon and the heavier wall tanks (he didn't mention). And of course sending units are an additional charge.

I have been away from the forum since the website change over, primary due to work. The spring time is our busy time and it looks like the economy may be improving a bit. We will top our annual beachmark this year with cleaning over 350 fuel tanks.

For you guys with diesel fuel, be darn thankful you are not using gasoline......

 

[psneeld]

Talking with the tank fabricator we use here in St Petersburg last week regarding pricing and the wall thickness came up. For tanks less than 100 gallons the wall thickness is around 1/8" then over 100 gallons wall thickness is 1/4". From what we can estimate when sounding tanks and probing during cleaning is the ballfes are no more than two feet apart. When we cut tanks open, baffles are fab'd from the same outside material.

For pricing; up to 100 gallon tanks are $10.50 per gallon and the heavier wall tanks (he didn't mention). And of course sending units are an additional charge.

I have been away from the forum since the website change over, primary due to work. The spring time is our busy time and it looks like the economy may be improving a bit. We will top our annual beachmark this year with cleaning over 350 fuel tanks.

For you guys with diesel fuel, be darn thankful you are not using gasoline......

Thanks for the info...got a bit of thinking/designing to do...

Mind releasing the fabricators name...might be interested.

 

[Forkliftt]

Thanks El Sea. Great info!

 

[swampu]

Aluminum would be my last choice

Why is that? I just replaced 2 of my 250 gallon tanks and had the other 2 rebuilt, They are 8' long and 2' x 2' (height and width) I think mine are thicker than 1/4", I think they are a little less than 1/2". There are two baffle's making it into thirds with small cut outs on the corners in the baffles. The two new tanks were 5k for 500 gallon, 10$/gallon. The two I had rebuild were pressure tested and had new bottoms welded on as well as several patches and 6 16"x16" patches on top were I cut out to clean them. That job for both tanks cost $1,400. Not bad, I know it's a lot of fuel but we will be running the boat about 60-80 miles out and staying for at least a week at a time running on the genset. 1 mile/gallon running and 1.7 gallons/hour on the genset would add up to about 400 gallons for a week running the genset 24/7. Good luck an what ever you decide.

 

[psneeld]

Why is that? I just replaced 2 of my 250 gallon tanks and had the other 2 rebuilt, They are 8' long and 2' x 2' (height and width) I think mine are thicker than 1/4", I think they are a little less than 1/2". There are two baffle's making it into thirds with small cut outs on the corners in the baffles. The two new tanks were 5k for 500 gallon, 10$/gallon. The two I had rebuild were pressure tested and had new bottoms welded on as well as several patches and 6 16"x16" patches on top were I cut out to clean them. That job for both tanks cost $1,400. Not bad, I know it's a lot of fuel but we will be running the boat about 60-80 miles out and staying for at least a week at a time running on the genset. 1 mile/gallon running and 1.7 gallons/hour on the genset would add up to about 400 gallons for a week running the genset 24/7. Good luck an what ever you decide.

It's not a distant last choice.

All tanks need to be built correctly, installed correctly and protected from the environment/accidental whatever. Any can suffer the consequences of not doing something right.

I just have had bad experiences with aluminum (it's not necessarily the miracle product many lead you to believe), and some other "pros" have written articles pointing out the same weaknesses (mostly corrosion) I feel so there's a bit of confirmation of my life experiences.

But I may even go with my last choice just because it may be the easiest/most inexpensive to get for my boat....and as I said...it's not a distant last...just last in a very close pack.

 

[Aquabelle]

Those contemplating replacing older tanks with new tanks of substantially different volume and/or location, should be aware that the boat's designer planned the location and weight range of the original tanks with the vessel's trim and stability in mind.

 

[psneeld]

Those contemplating replacing older tanks with new tanks of substantially different volume and/or location, should be aware that the boat's designer planned the location and weight range of the original tanks with the vessel's trim and stability in mind.

true but it's pretty easy to see what will work or not if you have an eye for it and a little common sense.

adding might present more of a problen...but not necessarily any more than downsizing. Keeping the same footprints and possible volume/weight levels less than what would have been there before.

Compare that to adding one or two people standing there in the salon...not really all that hard or scary.

 

[swampu]

The tanks in my vessel were installed in the 50's. They were installed on 2x4's that were on edge. The only problem with corrosion was were they had nailed the wood frame together. Were each nail was the aluminum was compromised. I've installed them with nail free wood at the contact point and bought some heavy duty rubber to install between the al and wood. Your right though, when they go bad they sure put a bad taste in your mouth.

 

[psneeld]

The tanks in my vessel were installed in the 50's. They were installed on 2x4's that were on edge. The only problem with corrosion was were they had nailed the wood frame together. Were each nail was the aluminum was compromised. I've installed them with nail free wood at the contact point and bought some heavy duty rubber to install between the al and wood. Your right though, when they go bad they sure put a bad taste in your mouth.

Especially when it looks like the rest of the tank could last 1000 years more!

 

[Aquabelle]

I've seen old tanks removed and replaced with smaller...and the vessel trimmed bow-down: not good. I'm just saying be careful. Also drastically reducing fuel capacity will impact selling prices.....surveyors will note it (on the other hand, they'll be +ve about new tanks of course)

 

[psneeld]

I've seen old tanks removed and replaced with smaller...and the vessel trimmed bow-down: not good. I'm just saying be careful. Also drastically reducing fuel capacity will impact selling prices.....surveyors will note it (on the other hand, they'll be +ve about new tanks of course)

Again...it's not for everyone, but anyone with some experience can figure out the trim issue easily and/or ballast if necessary which will improve stability... if done well.

As far as tankage changing price....I think you are right in that it's a push for new tanks vs smaller tanks...some boats...the effect on price would be negligible...plus the smarter buyers will recognize the improvements