I'm needing some advice with locating a diesel tank in my motor sailer. One option is for the cylinder shaped tank to Be placed athwart under the cockpit. As I will be motoring and sailing at times with the boat on a lean is there a way to run the fuel line so if half full it doesn't suck air? If I run a line out from each end with a lower Y join? ( I'm a novice at this )

Gutiz that approach sounds like a recipe for sucking air, which is not ideal, if that's your only tank location perhaps a take off amidships might be a better option. Is it a gravity feed set up ?
Not gravity feed as the Yanmar will pump fuel. It's too long to fit length wise there so the other possible location is under a bunk on the port side. This is not as low in the hull re getting the weight as low as possible.
Not gravity feed as the Yanmar will pump fuel. It's too long to fit length wise there so the other possible location is under a bunk on the port side. This is not as low in the hull re getting the weight as low as possible.
Hi, it appears that the tank really is inappropriate for the location, perhaps it's time to seriously contemplate one that is, I believe that diesel safe plastic tanks made to fit the available space are not really all that expensive. Or possibly if you are good with fibreglass that could be an alternative.
I would be trying to install it vertical. If it does not have baffles that would stock fuel slopping about.
Thanks for the suggestions l. That tank is 300mm diameter and one meter long capacity 70 litres. The one Ihave always had mounted in the transom is also 300 diameter at 600 long giving a capacity of 40 litres. It has a cone shaped sump that I regularly drain so I might remove it from the transom and put it length ways under the cockpit floor towards but just off the centre line. The longer tank might be better placed under the deck on the port side and boxed in to make a seat. Not ideal because better to position low as possible but it seems the most suitable for space etc. This way it is also for and aft and could be used as a reserve holding tank so as to keep the 40 ltr tank topped up. Here's a pic of the shorter 40 Ltr tank in position:
And on the concrete to show the sump.


I think this is a better solution
Diesel being approximately .85 kg/ l that brings your 70 litre tank in about 60kg. Not a great impost
for a ballasted vessel, also easily offset by holding or water tanks. Interestingly on my AWB I installed a generator Honda 11hp, I guess 6kva, two blokes can handle it ok, there is some additional ballast in the rudder compartment to compensate for the 6 cylinder GM being replaced with 4 cylinder job, anyway it was obviously causing a list and the ballast need to be rearranged, note the AWB is a motor vessel so doesn't have a ballasted keel to offset the top hamper of a sail vessel