but I am not convinced!

Just a picture from a naval magazine

Now judging by the deep level on concentration of the after planesman face [right of the hand*] who controls the angle of the dive, and the fore planesman's face [to his right] who controls the depth of the dive,  one could believe that the boat is dived on the watch [by just a third of the crew approximately]  instead of by the whole crew at diving stations. Mind you, the afterplanesman [always a senior rate] doesn't appear to be looking either at his depth gauge or his clinometer [spirit level bubble] but in between the two devices. Now take a look at the three depth gauges - two identical large gauges with a small one in between - forget the two smaller ones below. The large ones are for surface to mid-depth indication: the small one is for mid to deep-depth indication. When going deep, the two large depth gauges are shut off and only the small one is used.  All three show that the boat is on the surface i.e., they are showing zero feet.

* The hand belongs to the panel watchkeeper, an ERA or an Engine Room Mechanician, and they control the diving and surfacing systems plus the trim of the boat before and after diving, for either fore and aft leveling or overall weight of the boat for a quick dive or a more leisurely dive.

 Now look at the periscope, the after one of two, where you can see one of the control handles : there is another handle at 180 degrees to it.  Note that there are two plugs hanging on chains, dangling in mid air. Note also that there are two pipes [joined together approximately half way up] which are connected to the holes vacated by those plugs. This is part of the periscope desiccation process, where to dry the inner parts of the periscope mirror systems, warm air is pumped in on one hose and the damp air is sucked out on the other hose. This is done in harbour!

So, all in all, a recruitment photograph taken in harbour with the men dressed in their clean, neat and natty No8 working dress, instead of the "pirate rig" allowed at sea in lieu of service uniforms.

Moral of this story: either get the photograph right or make sure the title of the photograph is right.