If you are trying to get to the one that is being built you need to go through the warehouse entrance.

After you set the explosives on the second tank go in the warehouse( I think it's across the way) take out the guard and go from there.

Stuck in the tank depot, found 2 of the tanks, but can't get to the 3rd, stuck behind barbed wire - any ideas????

go around the wire

have tried, can't seem to find a way through, whereabouts?

i found my way around. go the length of the wire until you run into something hard like a wall. other than that i dont remember