Jonathan_S wrote:saber964 wrote:IIRC the SS Beaverford was a faster than normal merchant ship. Also she ducked in and out of the smoke screen.
Wiki confirms she was, steam turbine powered and capable of 15-16 knots. Whereas iirc most merchant ships of the day were more like 10 knots. Though SS Beaverford was no faster that HMS Jervis Bay. The difference in their relative survival times seems to be largely due to the smoke screen. Though I don't have info on the relative acceleration and turning rates of the two ships. It's possible Beaverford could dodge around more effectively - and with just pop guns if seems that there would be less temptation to hold a steady course to improve your own gunnery. So the smokescreen may not be the only significant factor.
Yes and no on the speed of merchant ships. It really depended on what the merchant was hauling.
Passenger and passenger/cargo ships were typically the fastest at 21-24 knots.
Perishable goods or refrigerated stores were typically 18-21 knots
The rest were dependent on size and cargo type but ranged between 8-14 knots
The Liberty ships depending on engine type had a speed of 10.5-12.5 knots
The Victory ships were faster with some reaching 18 knots but most were 16-17.5 knots
During WWII they had two different convoy speeds.
Fast 7 knots speed of advance
Slow 5 knots speed of advance
Speed of advance was the ships cruising speed with zig-zagging factored in which was 2/3 of a ships cruising speed.