Alden Challenger fuel tanks, one experience.

TomY

Alden Forum Moderator
Jun 22, 2004
2,664
Alden 38' Challenger yawl Rockport Harbor
949-Y, our boat, had the telltale stain at the hull keel joint on the aft edge. This was a symptom I was looking for when I surveyed the boat. These tanks are of course simply the fiberglass hull with a forward and aft bulkhead, flange around the top and steel cover plates bolted on. My boat has a sump just aft for the ice box drain. These large tanks(80 gallons from the day of gasoline engines and increased tankage demands) are baffled as well.

I often wonder if these large tanks were considered as a portion of the ballast as they are low in the keel and of course below the waterline. Maybe Bill can offer some insight on that point as his dad was involed in the design.

Neils Hellerberg at Alden advised me on how they approach the problem and here is a summary of what Alden prescribed:

Cut the tank tops off, cutting around the steel tops to leave the glass flange later for attaching floors for supporting the teak and holly sole later. Cut out baffles, grind, etc. and of course clean area to remove diesel residue.

Have two aluminum tanks built, about 20 gallons each to fit each side of the centerboard trunk. There may be space left over for a waste tank as well. Great idea.

Install new floors(framing) over plumbed tanks, soles next, done. A great idea and a big improvement to the boat. But I haven't done it yet, now five years later and here is why.

Contacting the previous yard, Burr Bros. in Mass. that cared for the boat for more than a decade, the yard foreman quickly affirmed the small oil stain at the aft edge of the keel. This boat was given carte blanche at the yard to perform what was needed. Every year they checked the water seperator and never found any. They were diligent about this.

As we know, this is not a pollution problem. Water pressure below the surface forces seawater into any opening in the tanks(or hull, result-sinking!). Water enters the diesel tank, runs through the seperator until it is full(of water) enters the injector pump and ruins the pump.

Burr Bros decided to quote "let sleeping dogs lie" and never saw water ingress.

I think one day I will perform the upgrade as it would be a great improvement but for now I'm leaving the dog alone.

Incidentlally, now I block the boat just aft of the keel joint and guess what, no diesel stain at the joint. Apparently, diesel being more viscous than water, found a tiny opening when the weight of the boat pushed the keel and of course a keel bolt, enough to allow this winter seepage of a few drops. In the water, the keel is of course hung from the boat closes the tiny opeing. I suspect most leaks could be atributed to the keel bolts but I would also suspect the centerboard trunk area as well. When they do leak, it sounds like it is difficult to find and repair and may be easier to convert to new tankage.

There are not many of us here yet but hopefully more tank experiences(and owners) will show up.
 
Jun 28, 2004
50
Fuel tanks - similar experience

Whisper (949-LL) had a similar fuel stain below the aft end of the keel-hull join. After recaulking the seam it disappeared for a few years, but has reappeared. In addition the caulking gets squeezed out after the boat has been sitting on the ground. It looks like the same situation Tom described, and the leak, which is extremely small, is caused by the load being taken off the nuts and washers at the top of the keel bolts, which are in the fuel tanks. A look through the fuel gauge hole in the fuel tank shows a shiny bronze nut and washer on the keel bolt at the bottom of the tank.

I haven't had the covers off the tanks, but will have to sometime, since the iron plate is corroding and won't last forever. Good thing it started thick; I've scraped and chiseled a lot off already before repainting.
 
Jun 22, 2004
47
Hunter 35 St Augustine
Fuel Tank

Well we launched Black Pearl on July 2nd and the fuel tanks immediateley filled with water, so I will be doing a refit this winter with a lot of research. The fuel tanks were placed low as ballast in order to get around the cca rating. A great idea but I am now paying for it. Chan Mosher has dealt with this before and I will be talking to him further. The culprit is usually the top of the fule tanks where the keel bolts are attached.
For the summer I have installed a 11 gallon tank in the cockpit locker.
We had some wonderful sails over the 4TH but I located a leak over my wifes bunk. This didnt go over so well with her.
I have rewired all the engine connections and the engine seems to be working fine.
The boats back in the yard for a week getting the water system up and running and the head plumbed with an electrosan.
My Sails should make it through the Summer but do not fit the new Mast very well. I am also installing a spinaker track in the hopes of getting some speed down wind.
 

David

.
Jun 17, 2004
115
Macgregor 26x Morecambe
cleaning tanks

What is the best method of cleaning the tanks? The interior of my tanks are pretty nasty. I had planned to use TSP, but I'm not sure if that will be strong enough to cut through everything.

This last weekend (with the help of a visiting brother) I removed the nuts off of the top of the steel plates, removed the plates, and removed most of the bolts from the fiberglass flanged area. I used a grinder to grind off all the bolts before unscrewing them from the inside of the tanks to make the task a little easier. I still have a few stubborn bolts that I'll probably need to drill out.

I have seen no indication of leaking, but based on other experiences here, it may be prudent to do as the others have an use aluminum tanks. Did you have these fabricated or just buy something off-the-shelf that seemed a close fit?

i had planned to clean the inside, grind the rust off the plates and paint the outside of the plates, put gasket putty in place of the old gasket, bolt on the plates, and then pressure test them to verify no leaking. Not sure if I need some type of barrier coat to keep the diesel out of the fiberglass.

If you have any suggestions, I'd love to hear them.

David
 

Orca

.
Jun 27, 2005
9
Hoping to bring this thread on top, but also to find out if anyone has recommendations as to cleaning and/or replacing gaskets on the fuel tanks. For the last several years I've been experiencing water intrusion into the fuel tank and have been living with it with frequent filter checks and water removal, but after having been on the hard for three months this summer, I had excessive water in the fuel after being in the water for less than three weeks and suspected keel bolt leakage. The lids are now off and the tank is dried out and, of course, no leakage from the bolts or lids can be observed. I've been using several degreasers, such as "simple Green", Dawn soap, and elbow grease, but would like the tanks to be more clean. Any suggestions? The gasket material (rubber, similar to wet suit material) has been satisfactory for the last 50 years, so I'm looking for a similar material.

If anyone hasn't cleaned their tanks and lids, they're in for a shock when you see what your filters have been doing for you.

IMG_2399 by rljend, on Flickr

IMG_2401 by rljend, on Flickr
 
Jun 28, 2004
50
Wow, I thought that Whisper's tanks were full of junk when I cleaned them out. I recall that I felt very lucky that the rust in the tank had not plugged the pickup at some critical time.

You can check my posts under "Dirty fuel tanks" a few years back which chronicle my cleaning out the tanks and replacing the covers. I replaced the gasket and have had no leaks since that was done. After all this has been done, I think that Tom's solution to replace the integral tanks with separate tanks is a good one. That way you could have two separate tanks, plus room for a holding tank in the forward part. Nevertheless, replacing the covers is simpler (even I could do it) and cheaper.

If you have any questions, feel free to contact me.

Rick
 

TomY

Alden Forum Moderator
Jun 22, 2004
2,664
Alden 38' Challenger yawl Rockport Harbor
Holy cow! I'm glad you brought this thread up Orca. Keep us posted as to your progress. Things are really slow in here but I check in often.

I haven't done a thing to my tanks since I posted that concern years ago. I still get a small stain every winter after a few months(no sight of it yet this year after a couple months, might be frozen solid!). I do drain a few ounces off the water separator each spring, but I've yet to see even a drop of water in 13 seasons.

I change my fuel filters, primary and secondary, every other year, I haven't had the engine quit since a single episode about 5 years ago, due to a clogged filter.

I think I run a little more than 70-80 gallons through each season and I really shake the boat up! Could my tanks be very dirty? I guess it's time I pull the fuel sender and pump out a few gallons from the bottom this winter.

Anyone else still running on these tanks with no known cleaning? I don't know if mine were cleaned in the 35 years before I owned the boat.
 

TomY

Alden Forum Moderator
Jun 22, 2004
2,664
Alden 38' Challenger yawl Rockport Harbor
I finally pulled a fuel sample from my tanks.

Orca's photos prompted me to do so. But I've been having no filter problems, in fact, I change the primary and secondary every other year(about 200 hrs engine time). Also, the boat is shook violently, to it's beam ends, a few times a season.

I pulled the fuel gauge. That's nifty piece of hardware. A "Crittenden" Rochester mechanical gauge. Appears to be all bronze including the float, and it still works like a charm.

I used a cheap drill pump(I use it to change the oil) with a section of garden hose long enough to reach the bottom of the tank. Filled two 2 litter Coke bottles first. They were clear as a bell! That made no sense,...so a couple days later, I pulled another sample.

This time I was careful to straighten the hose and feel the back edge of the tank, and I believe it was as low as you could go. This time, I pumped about a gallon into a shallow pail. I did in fact pull some sediment out. Fine sand sized, black particles on the bottom of the pail. Not enough to cover the bottom of a thimble. I also had one dime sized water plug in the bottom(I've yet to find water in Racor 500 bowl).

As best as I could, with a flashlight, I could see the edge of the baffle which looked clean. Also with a small inspection mirror, the bottom side of the steel plate looked reasonably clean and scale free. With that, I wire brushed the fuel gauge which had a black thin paint-layer thick coating. Cut a new gasket, and bolted that back down.

Maybe this is just lucky. I'm fairly certain these lids have not been in off in the last 35 years(I have a good history of the last owner-longest owner to date). I'm satisfied now with the state of the fuel tanks. I wonder why some tanks go so bad so quickly and others(like these) seem to be fine? Is it the climate the boat is kept in? Maybe the regular use and fresh fuel my boat cycles through?
 
Jan 27, 2012
12
I've cleaned many fuel tanks on our tugs- a little different though as our big tug holds 38,000 gallons in 4 seperate tanks. There are man hole covers you unbolt and then climb in with a pressure washer and detergent. The black crud (we fondly call it whale buggers) is from a bacteria that grows on the interface between the water in the bottom of the tank and the fuel. I've been told it eats fuel and this stuff is the by- or may be end- product. If you keep the water out you have very little problem. I wonder if there is a little water intrusion around the keel bolts and this supplies the necessary formula for bacterial growth.

There are products on the market that can be used to keep this problem at bay. We've used Biobor with success but beware! the first time it is used the crud is emulsified and thus goes directly to your filters rather than staying at the bottom of your fuel tanks. Just be prepared to change a lot of filters to start with if you do have a problem. Obviously the best solution is to clean the tanks and then use a biocide to maintain things.
 
Dec 30, 2013
3
We own 959A, Diana, and she had water leaking into the fuel tanks. I looked at the posts concerning fuel tanks and did not find an easy answer. The tanks on the Zephyr are essentially the same as the Challenger. Finally after working around the problem for several years, last summer I had Hartge's pull the covers on the tanks. I think only two of the bolts had to be replaced. As others have found the tanks were very dirty and were cleaned. In addition and the answer to the problem; a number of the keel bolts, the tops of which are at the bottom of the tanks, were broken. All the keel bolts on the Diana were replaced. The original steel covers were sandblasted and painted with a special paint designed for oil tanks. New gaskets were fitted. Problem solved. Pictures are available.

J. Frank
 

TomY

Alden Forum Moderator
Jun 22, 2004
2,664
Alden 38' Challenger yawl Rockport Harbor
J. Frank said:
We own 959A, Diana, and she had water leaking into the fuel tanks. I looked at the posts concerning fuel tanks and did not find an easy answer. The tanks on the Zephyr are essentially the same as the Challenger. Finally after working around the problem for several years, last summer I had Hartge's pull the covers on the tanks. I think only two of the bolts had to be replaced. As others have found the tanks were very dirty and were cleaned. In addition and the answer to the problem; a number of the keel bolts, the tops of which are at the bottom of the tanks, were broken. All the keel bolts on the Diana were replaced. The original steel covers were sandblasted and painted with a special paint designed for oil tanks. New gaskets were fitted. Problem solved. Pictures are available.

J. Frank
Hi Frank. Please do post any photos. In the beginning you said 2 keel bolts were replaced, then you said, "a number of the keel bolts were broken". Can you clear that up?

This is a common problem area and any photos of the tanks, closed, opened, etc. are an enormous help. Thanks.
 
Dec 30, 2013
3
Tom

Sorry for the confusion. The first reference to bolts was to the bolts that hold the tank lids in place. Each cover plate has between 40 and 50 bolt; I did not count them. These bolts are epoxied in and we were surprised that only two could not have the nut broken loose or cut off. They cleaned up OK and new nuts were used.

The keel bolts, as mentioned, terminate inside the fuel tank at the bottom. They were 5/8 inch bronze and had a square plate, about 2 X 2, and a nut. The new ones were glassed over.

The aft cover is shown in the picture before sandblasting. The fuel gauge was repaired. The forward cover was rusted more than the aft but on the outside of the tank.

J. Frank
 

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