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SpaceRnglr · 12-04-2018, 09:13

Wife said diesel smell had to go so the project to inspect the tank moved up the list. I am glad it did as when I removed the tank there was a puddle of diesel under the tank. I think the tank had a small leak, but a very slight poke with a scraper went straight through. Time for a new tank...

I have posted a picture of Elessar's tanks and a schematic of current and options. Elessar has 1 diesel tank (~180 liters) and 4 water tanks (310 liters total). She also has a water maker so I think I can live with less freshwater. The idea is to convert one of the water tanks to diesel. Actually it will have to be a new tank as the water hose connections are on the bottom of the tank...

There is very little space around the tanks so I need small and simple. Does my schematic below look reasonable? Any comments on either of my alternates?

RaymondR · 12-04-2018, 10:36

Why not just replace the diesel tank?

Sailorman Ed · 12-04-2018, 11:03

We had the same issue, took out the AL tank, wirebrushed it and ended up with lots of pinholes. Took it to a shop and they "wrapped" the bottom, did a nice job welding it on, leaked tested and painted for us.
Not cheap but a fraction of the cost of a new one.

SpaceRnglr · 12-04-2018, 15:56

Quote:

Originally Posted by RaymondR

Why not just replace the diesel tank?

The diesel tank will get replaced with a copy of the current tank. Getting access to everything was quite a job so I thought while I am at it i can convert the water tank to get more diesel storage. The I would have 2 diesel tanks good for about 28” litres. Not sure of best practice in the plumbing and hence the question.

01kiwijohn · 13-04-2018, 08:13

would it not be practical to have a plastic tank welded up? I have a Vetus, plastic, 50 gal tank on the boat I bought and it seems to be doing the job. It stays very clean, won't corrode and doesn't require a fuel gauge as I can put a flashlight on it and see what's in there. (I did put graduated level lines on a tape, applied to the outside, where I can see it from one of the cockpit lockers.)

Seadoc777 · 13-04-2018, 09:00

I carry 120 gal of bio diesel. I switched from petroleum diesel five years ago to get rid of the smell. Bio can be hard to find I get mine in Marathon Florida at $3 per gallon. I have a 41’ ketch burning one gallon per hour at 2500 rpm - fill ups are infrequent. Sometimes I am asked if I’m baking cookies? The French fry story is slightly true. Try it you’ll like it.

Lodesman · 14-04-2018, 07:04

How about a third option?
I see your plans as being somewhat backwards. The large tank should be storage, and the smaller tank in use (day tank). Leave the fill arrangement to fill the 180L tank. Reverse the pump in your middle diagram to fill the 80L tank from the 180L tank, and run the 80L tank to the Racor/engine. You'd have to put the fuel return line back to the 80L tank and I recommend a separate vent for it.

SpaceRnglr · 14-04-2018, 07:54

Thanks for the good feedback on plumbing. Actually I would like to run dual fuel lines to the engine as described by Scout 30, but I don't have space for all the necessary fittings and pumps where I need them to be. Same problem with Loadesman's advice, it is very difficult to get fuel lines from the smaller tank back to the engine. That is why I was thinking just a simple connection from the smaller tank to the bigger one would work best.

Actually, all this has me thinking... The best place in the boat for fuel tanks is under the aft bunks. I have the original manufacturing drawing and this is where they were originally shown, but they were scratched out and moved to the current location (I believe at the factory). I am tempted to install 2 larger tanks in that location as it would allow plenty of space for the dual fuel lines to the engine.

My only issue is that the holding tank and water heater are located under the bed. I think I could install a holding tank where the fuel tank was located, my only concern being it would be shaped like a pancake and that might make it hard to suck out all the poo.

Argh - why is it that all boat project start as a "let me just have a peak under the diesel tank" and now have me contemplating having 3 new tanks made, changing every diesel fitting on the boat, changing all the low pressure water system, reinstalling the hot water heater, and replacing all of the toilet piping...

Most alarming, I got a quote from a local aluminum fab shop that makes small boats and they want US$2,600 for a not-very-complicated 190 liter tank! What does BOAT stand for again, I think I forgot...

Deepdraft · 12-04-2018, 13:11

I had a small leak in a 30yo steel tank. I ended up cutting the top of the 70 gal tank out. I inserted a fuel cell from ATL, using the old tank sides and bottom as support. The poly tank comes with foam inserts that can be removed in order to collapse the tank and squeeze it through the available floor access. In my case it was a 13 inch square. Once the poly tank was inside the foam can be reinserted. I’ll upload a few pictures.

http://atlinc.com/marine.html

Regards,
Neil