Q1. Yes, mainly surface vessels and aircraft

Q2. Yes, new Sonar determine direction, range, and depth, and controlled the Hedgehog launched contact charges (18 fired at once in a circled area circumference). Later, the squid 3 depth charges were controled and fired with sonar guidence. New aircraft radar could detect a surfaced U-Boat at a 26km range. Hunter/killer groups; these ships were dedicated to U-Boat detection and destruction.

Q3. Late 1943 extremely deadly

Q4. WWII U-Boats were designed as a surface vessel with the ability to submerge. They were limited to about 2 days submerged at very low speed. The Type 21 was the introduction of a U-Boat that was desogned for submerged travel, but it's arrival was too late in the war for Germany.

Q5 Definitely, The Brits and the US Navy knew the moves of the German Navy in real time. The UK and the US developed the Bombi machine [The National Cash Register Co. (NCR), Dayton, Ohio, built many of these machines for use by the Allies]. These could decode the enigma intercept extreemly fast.

I hope this helps,

Regards,
Don_

"A man's got to know his limitations..."
Harry Callahan, SFPD