1) Things have changed with the advent of nuclear-powered submarines since the 1960's, but WW2 submarines were small - and had a small crew. Even the largest U-boats, the Type VII and it's cousins, were only 67m (220 ft) long, and with a deck only about 10 feet wide for most of the length. They are quite a bit smaller than even the smallest destroyers, and with a much cleaner deck,as shown below for a late-war u-boat.
Type VII U-boat
Even under North Atlantic combat conditions, it is hard to imagine being on-deck without being aware of what else is happening in those close quarters.
2) Yes, there were protocols for diving.
Note specifically from (56) below: "The Commander is personally responsible for opening and closing the conning tower hatch.". The buck, very emphatically, stops with him. However (47) - "The senior man in each room reports readiness to dive to the Engineering Officer." also means it is the responsibility of every team lead to ensure no-one is missing from their station before reporting readiness of the room/team. At every stage of the dive preparation, not only is every order repeated at least twice, but every man expects to be notified, and aware, of the overall boat status.
Section I - General Regulations
A. Instructional language and commands
All orders, reports and feedback given while flooding, diving, surfacing, blowing etc. are to be repeated to guarantee they are understood correctly. The report of execution must follow every order.
When orders concerning the operation of shut off valves are given only the words "open" and "close" are to be used. In feedback about the position of the valve only the words "on" and "off" are to be used. Words such as "shut, tight and opened", are prohibited.
Only standardized nomenclature (in accordance with the sketch book) is to be used in the naming of piping, shutoff valves etc.
B. Diving board, assignment board
Diving boards listing the steps which must be taken to prepare for diving are issued for every type of boat. The sailors who implement these measures or must take over responsibility for correct execution are listed on the assignment boards.
The measures concern:
I. Upper deck:
II Below deck:
By compartment from aft to forward.
Section III - Readiness to dive
- The Commander gives the order:
Commander: "Prepare to dive",
if necessary with restrictions (e.g. "except for diesels")
If circumstances require, it is first ordered:
"Upper deck prepare to dive"
"Below deck prepare to dive".
- This command is only given to the Engineering Officer. The Engineering Officer repeats it and passes it to all rooms verbally man to man.
B. Actions to be taken
Actions to be taken by the Watch Officer:
a) prepare the upper deck to dive (Seamanship),
- Explanation of 43:
In preparing the upper deck to dive the following directives are to be particularly emphasized:
No loose items may lie under the upper deck. All objects, such as lines, fenders, torpedo loading device, gangway, dingy, must be lashed, so that they cannot be knocked loose and foul the anchor or rescue equipment, air, diesel exhaust and vent ducting or also the propellers. The dogs of all access hatches and other fasteners must be checked for proper closing. Attention must be paid to the fact that the access hatches are closed correctly and do not rattle. The signal buoy (if installed) must be latched and secured. The drain and plug screw of the dingy must be open.
In readying the bridge, attention is to be paid to the fact that all folding seats are well secured because otherwise, they will rattle during submerged cruise. All wooden gratings need to be checked.
The speaking tube cocks are closed on the order of the Commander. If they remain open at prepare to submerge, they must be closed not later than by the closing of the conning tower hatch.
- The senior man in each room reports readiness to dive to the Engineering Officer.
The Commander receives the following reports by the Watch Officer (meaning the responsible Section Officer in each case):
a) "Upper deck ready to dive",
b) "Torpedo armament ready to dive",
c) "Artillery ready to dive" and
d) "Communications ready to dive".
- The Commander is personally responsible for opening and closing the conning tower hatch. After opening or closing the Commander notifies the boat:
Commander: "Conning tower hatch is open or closed".
After the ready to dive condition report has been issued there should be no interruptions. If however, an interruption is necessary, the Commander, the Engineering Officer and the Watch Officer must be informed simultaneously.
- Condition of the boat:
Boat is ready to dive, crew is at diving stations.
Orders and reports:
Commander: "Closing conning tower hatch".
Commander: "Conning tower hatch off. Negative pressure test".
The Order: "Coning tower hatch off" is passed to all rooms verbally man to man.