WOW ! this is some dive , no BCD ! my hat is off to you ! I love U-boats but for this depth I would do the ANDREA DORIA first . As to the ammo locker hatch, in all my dives this hatch is under alot of silt and to me not worth making a deadly cloud of silt for rusty ammo that in every boat I was on the charter boat captain made that diver throw the stuff back over the side, even when I use my buddies boat he would not allow any of this on his boat! If you want it will be found in the floorboards just after you pass through the control room hatch going towards the radio room. I have never been diving in Greece so I do not know the bottom conditions, is it more sandy than silt/mud ? , if so this is better for you , if so just stick your hand in the sand and feel for a hand catch and pull up ( this should be in the center of the trap door in the floor boards). May I ask what are looking for U-boat ammo or just trying to avoid it ?If you look at pictures of a u-boat before it was sunk ( may I suggest DEUTSCHE U-BOOTE GEHEIM 1935-1945 by RICHARD LAKOWSKI ) and when you enter this boat you will be in for a big shock! EVERYTHING is covered in silt and rust, the floor covered over in silt / sand ,wires hanging down , rotten wood from the oak wall paneling etc.Getting into the boat via the conning tower hatch I take off my DACOR BCD/tank setup and enter the control room,hookup my penetration line to the bottom of the ladder then put on my tank. When I started diving on U -boats some 20 years ago things were not as bad as today,as time goes by the more these boats fillup with sand and silt. When I first dove the U-853 she still had her 37mm gun barrel and flak shield still in place, this has now fallen off. I would respect any unexploaded ammo laying about but would not worry about it , I would be more concerned about your exit points, if you kick up a silt cloud stay ahead of it and get out as soon as possible. If your exit point is where you started from and you must go through a blinding silt cloud this is where your penetration line with glow sticks attached comes in as your life saver ( no joke ,I know this first hand ).