Many fuel tank drains don't have a sump, this one included, which makes a drain pretty ineffective. Among my makeshift tools I keep at work is a cheap inline electric fuel pump (exteral, not tank mounted) with a filter and hose attached that I run from a booster pack. I actually have two, one is dedicated to fuel only. That contraption filters anti-freeze for re-use, collects chunkies as you transfer fuel out of a tank for service, drains resivoirs, fills resivoirs, pretty much anything you want except gear lube, provided you're not in a terrible hurry.
One of the many things they are great for is getting into the CORNER of a fuel tank where a drain plug could never be effectively located. In the case of an M35 if I suspected water in the tank, or if I wanted to remove a couple of gallons of the "wettest" fuel in the tank as a PM on a regular basis, I'd back the left rear wheels over something I didn't want any more (a couple inches is all that's needed), remove the strainer from the filler neck, and stick the hose right to the lowest part of the tank. Which incidentally, I can now inspect provided the fuel is actually diesel fuel. That's actually a common task, because the cowboys at work who drive our tow trucks like to drive around with the fuel caps dangling from the tether chain all winter.