Webster

like RR said, they were ww1 boats so they were so old it was a crap shoot for them to just work at all.

with the speed listed at 12 knots that was the speed of the boats when new back in ww1 so add 20+ something years of wear and tear to those engines and then they reasonably shouldn't be able to put out that top speed but I wasn't going to make them un-playably slow so I settled on 10 as a reasonable speed a minority of very well maintained boats might be able to do.

it is realistic that unless the ships came right to you, there was really nothing you could do to attack them if they were not heading in your direction.

the best strategy with s-boats is to ambush like a sniper by hiding and let the target come to you and when he is in the kill zone you rise up and sink them.

almost without exception you are not going to be using your engines as much for setting up your attacks like you do with the fleet boats, its a different way of thinking for your strategy.

think of yourself as a slow moving fragile leaky mobile mine platform and your torps are your mines so you wait in a good spot where shipping will have to come to you then let then fly and drop into a hole somewhere and be very quiet hoping you don't die.