The Gascony was sunk by torpedo in January 1918. At the time there was some confusion as to whether it was a torpedo or a mine, but post war examination of U-boat records confirmed it was a torpedo fired by UC75, a submarine of the same class as UC70.
With the wreck virtually upside-down, then collapsed to starboard leaving the port side more exposed, getting your bearings is difficult. My trick in these circumstances is to take a compass bearing on the lay of the shot line before descending and to assume it will be reasonably similar by the time I hit the bottom. To get to the more interesting port side of the wreck head to the north or north-west side of the wreckage.
The stern is reasonably intact and almost completely upside down. The propshaft protrudes from the keel, but the propeller has been salvaged and as already noted, the rudder lies on the seabed below. A few plates have rotted through and fallen clear to provide some holes to look inside, but nothing big enough to comfortably fit through.
Descending the slope of the hull back towards the port side, there is a large hollow triangular section standing upright and a box section resting next to it. Interesting shapes, but not something I can identify as a particular part or function on the ship.
It is just forward of these that the most interesting part of the wreck can be found, the remains of a cargo of gun carriages. Heavy duty spoked wheels getting on for 1½ metres across, some broken, but many intact and some even still attached to their axles.
The area of the engine room is quite interesting. Tucked back beneath the plates are the remains of the propshaft tunnel and the crankshaft from the engine, together with the usual scraps of grated decking.
A broken cylindrical tube with coiled pipes inside is the remains of a condenser, a component that was often one of the first bits to be salvaged from wrecks of this age, but for some reason was never removed from the Gascony.
The four boilers are clear of hull plates and two are tilted at unusual angles. When the Gascony sank it went down by the bow and was seen to break its back before disappearing beneath the surface. This would explain how the boilers are clear of wreckage from the upturned hull and how the tip of the bow has noticeably twisted back relative to the line of the wreck. It has also twisted almost 180 degrees on the axis of the ship, because it is actually resting on its port side and you are suddenly on the starboard side of the keel! I can't imagine how the wreck could have collapsed this way, so the damage must have happened at the time of sinking. The wreck went down bow first, so maybe the bow was broken loose as it hit the seabed, with the rest of the wreck then rolling in the opposite direction as it sank.
Within the break lie the anchor winch and a large pile of anchor chain. On the far side of the wreck as we look at it, there is a swim through beneath the upturned hull, coming out across the wreck from the winch. I couldn't find anything of significance in there, but swim throughs can be fun just for the sake of it.