The object in the water is the top of the torpedo shown in the previous photo before it was lowered. I'm guessing that the photos show the torpedo being lowered into the water, rather than lifted out of it. Corrections welcome! The head of a crew member is just visible next to the torpedo in the water. The submarine has been identified by William Richmond Fell as HM Submarine L20. It is in a group of his 1928 photos from Hong Kong.
Date picture taken
1928 (year is approximate)
Comments
Practice torpedo?
On a tour of a military museum they showed us a practice torpedo, that didn't carry any explosives, and would inflate a float at the end of its run so it would rise up to the surface for collection and reuse. Perhaps that's what is happening in this scene? (Also see: https://gwulo.com/comment/53870#comment-53870)
Article on practice torpedoes
Very interesting article. Thanks David.