[LukeFF]

Yep, it's one of the cool things the devs added to 1.5: the ability to upgrade the sonar equipment. Early on in the war, you will have to rely heavily on your bridge watch to spot targets, because sonar doesn't track that far, and the early SJ radar has a max range of just over 7 miles. Come ~September 1943, though, and things start to really improve. JP-1 sonar and SJ-1 comes online, the problems with the Mark 14 get fixed, and the wakeless Mark 18 is introduced as well (albeit in very small numbers at first).

S boat fans...well, let me just say, get used to being the red-headed stepchildren of the fleet. No JP sonar, no SJ radar for the S-18s until November 1942 (and no SD radar ever), and SJ and SD radar for the S-42s starting only in March 1943.

Another nice little feature we did was make the Mark 10 cost 100 renown points each for the fleet boats. We wanted to mimic the reality of fleet boats taking Mark 10s on patrol but at the same time depict how this wasn't a common occurance. However, the biggest issue with this was trying to find a solution to a player just skirting around the Mark 14's problems by just loading up on Mark 10s each and every patrol. This solution still allows the player to load up the Mark 10 on the fleet boats but at a high cost. Of course, for the S boats they will remain free.