for ss2

you can keep 24/40 speed with :
1x super vetted engineer
1x airman
1x empty sonarman
1x full torpman
1x empty torpman (backward)
1x empty BO


for ss3

you can keep 24/40 speed with
engineer , airman, sonarman, torpman but empty BO and backward torpman
if you put belt + bulge or 1 more sailor into the R mount, your speed will drop to 23/39


for ss4, you can put 2 repaiman if you don't like machine gun.
Trust me, it don't work well

Thank you both for your advice. I will plan carefully.

As the other say enginer is better. For many reason, when you dive your speed decrease.
You need speed to be a good hunter. The repair only help when you ss need to eb repair.
But the enginer is usefull any time. And the other is that is you are a KM you will see
that the enginer of km have chief and the repair don't. think about it

Engineer.

A rep can be placed on the gun slot.

Speed is your friend, particularly when you don't have range.