Anyway, I think I've given Taricus too much time already. Let's discuss the other proposals.
Narwhal guided torpedo : A highly problematic design. Intends to be both long ranged yet reliant on wire guidance. Giving the expected survival time of any of our destroyers in the face of the enemy, I can not see this thing being effective.
UF-ATGM-41 Saltseeker' Pattern A : All in all, a pretty good idea. Unlike the torpedo, here the wire guidance is for fairly short range, not dozens of kilometers. Only worry is ambition, the shitty variant of this design was only made in 1951
UF-41-LFT "Golden Salamander" : Flamethrower tank. Should be good at holding the Jungle and storming fortifications, probably going to suffer in other areas. Has the advantage of being based on the salamander, and thus being nautically capable. This should benefit enormously when storming beach fortifications. (Oh, and includes finally fixing our attempts at Explosive Reactive Armor)
UF-41-HSB "Peregrine" : A jet powered light bomber. Should stop the enemy from negating our bomber advantage, and should the enemy naval advantage a bit.
UFN-DD-41 "Ranger" : Replaces the Bumblebee with rockets, gets extra torpedo tubes, and more goodies. Seems like it would run out of ammo in 2.3 seconds.
UF-41-VT : Proximity fuses, a design literally hailed as something that won the war, on the same level of importance as radar. Should dramatically increase lethality of all large caliber weapons. Any narrow miss becomes a hit, dramatically improving accuracy of all designs. May be a bit ambitious.
UF-ASA-41 'Overcompensator Mrk II' : A spectacular and daring investigation to see if Sensei has a difficultly level below trivial. Really, this is a revision.
UFAF-MTA-39 'Maximum Effect' A spectacular and daring investigation to see if Sensei has an expense level above theoretical. Really, 16 jet engines?
UFS-CV-40c Sea Haul An interesting idea to solve naval TC problems without having to deal with the Sea. Will not help us in the short term, and is hence not that usefull.
UFS-SUB-40c "Hunter" A rather peculiar submarine design. Includes a deck gun for if the captain is feeling suicidal, and a full radar and sonar system, making it the largest submarine ever designed. [Our radar is huge, it takes up an entire cargo ship]
UFS-CL-41 'Cavalier Class' Cruiser A cruiser which is the direct equivalent of the enemy Seaweed cruiser, except with slower firing weapons, no fire control systems, and designed by Forenians, who have no idea what they're doing.
Incompensation Actually, a very good radar design. Probably my second most favorite on the list currently.
Archer pattern S.T. "Narwhal Ranger!" Basically, a combination of the Narwhal design and the Ranger
Ana-bomb2000-1941-foo "Large Rock" Anti-radar missile An attempt to build a type of missile dating 1965, but with our current subpar radar tech
UF-RDN-1941-S 'Virgil' A rather conservative radar revision.