Here is the result so far of jos, Archie and myself.
Base is the story of Archie who visited this bunker part by entering via the door opening 4-5m above ground level (M1).
Some text is in Dutch, sorry for that.
One issue is that "people tell" that there is no passage between the part above the pump room and the side under the cupola.
According to Archie from point M1 (his entrance) there is a staircase going up (left) and one going down (right). As seen is the cross cut. He also entered the electrical room from this part of the bunker, which makes it a mystery where this room is.
One option is that there is a middle section with room(s) M3. But this conflicts with the staircase,
Also when there is a staircase going down you should think that there would be access to the ground level rooms BG2 and BG3.
- St Nazaire - Schleussebunker 107 - cross cut
- St Nazaire - Schleussebunker 107 - inside rooms
- St Nazaire - Schleussebunker 107 - side view
All rooms fit in the width given for the pump room which is 800cm. Except (!) the upper three crew rooms, B2, B3, B4.
I also did a comparison with the aerial picture from Dirk.
- St Nazaire - Schleussebunker 107 with Normandy lock door bunker.
Patrick your measurements on the aerial picture are not correct (sorry) at the right side. The last part is the side wall of the bunker and therefore not part of the overall width.
I made that mistake too but you can see the big groove from the roof going to ground level.