Thanks for all the input!
Just found out that the tank design I have now is the one I'm stuck with. I actually had not planned to build this tank for atleast another year or so. However, I was having a "few" beers with a friend and spitballing ideas about it recently and he offered to make me one at material cost. I immediatly accepted his offer ofcourse and a case of bear for his troubles! Unfortunately for me he informed me that he was leaving his company end of this month to seek his fortune elsewhere and then he would not have the needed equipment available anymore.
Ofcourse as always with this sort of thing I had to go to Singapore for work within days after our night out on the town. So the next day (ignoring the huge hangover) I pulled out and dismantled the old tank and gave him all the fittings. None of it will be reused as it turns out.. I had also done the measurements of the available space for the tank and we made a quick draft in autocat. I flew to singapore the next day which made researching, discussing design alterations with my friend, parts ordering etc. Quite challenging... The 7 hour time difference doesn't help either...
Anyway, very long story short... He sent me a messsage today that all the fittings have arrived, the cutting template is ready and that the sheet metal will be cut out somewhere next week
Picture of cutting template:
This is not the detailed one and some alterations have been made afterwards (including some extra baffles) but it will give you an idea.
The tank's shell (or whatever it's called..) will be cut out in one piece and then folded together so there will be only one weld running across the length of the tank.
All going well the tank should be ready and waiting for me when I get back home somewhere next month. It's not perfect and given time and I might have done it another way but in any case I learned a lot and was fun to do
Currently the unimog still sitting in a shed with half the engine dismantled, oil leaks from engine, gearbox and axles but hope I to have it ready in time for a trip to Iceland this summer together with another unimog and will let you know how the tank performed.
P.S. I did consider punctures and is one of the reasons I had it made out of stainless steel, its a lot tougher then aluminium or even normal steel. I also carry 2 jerrycans with fuel just in case...
(I found some really usefull tips on emergency field repairs of tank punctures on a dutch truckers forum, they have used everything from ratchet strap and rags to bars of soap, axle grease and ducktape...).
I thought about a dual tank system but I don't have room to place 1 tank higher to transfer it from (there is a container box on top). So the remaining option is to have 2 smaller tanks placed behind each other and use them as communicating vessels or separate with a transfer pump between them. I didn't want to have communicating tanks with a connection at the bottom because of the higher risk of tearing it of. I read somewhere that trucks ( lorry's ) with communicating tank always have the suction tank placed slightly higher than the storage tank).
