Eh, you want free rules on this stuff? By tomorrow? Ha ha, yeah right. The best I can do for you is to come up with some fast and light d20 rules for you.
Pretty much all you can do is assign HP, Hardness, Maneuverability, AC and Speed to each kind of ship, then give them weapons with range increments of your choice.
Here's a few examples (I know very little about the capabilities of the ships you're talking about, so I'm pulling these out of thin air here except for speed).
WWII German U-Boat (late model Type 45) HP 40, Hardness 50, Maneuverablity Class D, AC 15 Speed 200 Dive 20 Max Depth: 185
Beyond Max Depth the sub takes d6 damage per minute, ignoring hardness. Beyond 2.5 times the Max Depth (460 ft) the sub takes 1d6 damage per round.
Torpedoes: 4 racks 12 each. Speed: 310. Torpedoes work differently from normal shells. There isn't a "to hit" roll; send it on an intercept vector and hope it hits. Torpedoes can be shot at +-90 degrees from the shafts. If you want, you can substitute this for a "to hit" roll with a range increment of 310'. The max range on a torpedo of this sort is 27,720 ft. Penetration 80 Dmg 20d6.
20 mm deck gun: Range increment 400', Penetration 30, Dmg 10d6.
Sonar DC roll: 0 + 1 for every 50 feet of vertical or horizontal distance.
Real world data courtesy of
http://www.btinternet.com/~k.barltrop/u_specs.htm
Soviet Delta III Nuclear Submarine: Sorry, this thing's classified. Beef up the German submarine a lot and you should have a Soviet sub.
US Naval
Spruance Class Destroyer: HP 200, Hardness 90 Manueverability Class C, Speed 340 (actually, it's higher, but the real speed is classified. I've heard rumors that they can go as fast as 50 knots (Speed 575). Weapons: 2 5" guns (Dmg 40d6, Range 1000', Penetration 50), 2 20mm Phalanx AA guns (Dmg 3d12, Range 500', Penetration 20), 6 MK-46 Torpedo launchers (See torpedo rules above. Damage, speed and penetration should all be higher. Naturally, it's classified on ours.).
Research vessel: That doesn't give me anything to go with, really. Low HP and Hardness, with few if any armaments.
If you don't like any of my stats, feel free to change them. All of them except ship and torpedo speeds are fabricated. I'd recommend setting the average damage for each weapon to sink ships as fast as you think they should. If you think two torps should sink a destroyer, set the damage for the torps so that they do.
Hope this helps.
Destroyer stats:
http://www.chinfo.navy.mil/navpalib/factfile/ships/ship-dd.html
