Just a quick rundown of the vessels included in the game with some comments.
Salta and San Luis (German Type 209 class SS)
These show up in just one scenario (13D Falklands) where they are dueling with the British SSN Swiftsure. The Argentine subs are hard to detect with a detection value of 7 and two "no attack" boxes on the contact level track. They are dangerous offensively, with a +3 attack value, but may have trouble detecting targets with a senor value of just 2. A single hit always sinks them.
Shtorm (Kilo class SS)
Appears in Scenario 13G Turning the Tide as part of a wolfpack attacking a convoy. Hard to detect and track, with a detection value of 7 and two "no attack" boxes. Only takes one hit to sink. Offensively has a 3 sensor but just a +2 attack, making it mediocre in game terms.
Molniya (November class SSN)
Appears in Scenario 13B Search and Destroy where it's really little more than a target. The worst sub in the box, with a detection value of 5 making it as easy to find as a surface ship, a sensor value of 1 making it nearly deaf and an attack value of +2 if it manage somehow to detect something. Can possibly survive a hit with two boxes each in its sensor and attack value tracks.
Admiral Lapshin and Kotov (Victor I class SSNs)
Both appear in scenario 13F Mounting the Threat as reinforcements. Not as bad as the Molniya, but still not very good submarines. They have a detection value of 6 and only have a sensor value of 2, putting them at a disadvantage against the NATO subs. The +2 attack value is mediocre. Like most subs they have two boxes in the sensor and attack tracks, making some, but not most, hits survivable.
Ivan Rogov and Skvortsov (Victor III class SSN)
Much better subs than the older Victors, with detection values of 7 and sensor values of 3, making them competitive with NATO subs. Offensive potential is still relatively low, with a +2 attack value.These appear in several scenarios. The Skvortsov is in Scenarios 13A (Sub Duel); 13B (Search & Destroy); 13C (Breakout); 13K Flattop; 13L Wolfpack and 13M Convoy Screen. Her sister, the Ivan Rogov is in all the same scenarios except for 13B, and also appears in Scenario 13H (Boomer).
Dekabrist and Grif (Alfa class SSN)These are about equal to the Victor I boats, except their high speed means Close/Open Range cards played by them can only be cancelled by a random number draw of 4 or more. The Dekabrist appears in Scenario 13C, the Grif in 13M and both in 13L.
Sura and Donets (Charlie II class SSGN)
These subs are optimized for attacking surface ships, with a +3 attack value. Unfortunately they are also easy to detect (a 5) and have poor sensors (a 2) reducing their chances of actually pulling off a shot. They don't have much chance of hurting any attack subs, either, with just a +1 attack against subs. Both appear in 13G where they have a nice juicy convoy to attack. In both 13C and 13M one of the subs appears, and in each case its main contribution to victory is to successfully exit.
Bolshaya Neva and Yenisey (Oscar II SSGN)
Much more dangerous ships than the Charlies. While still easy to find, with a detection value of 5, they have a decent sensor value of 3 and an antisurface attack of +4 which gives a high probability of success. They're also tougher than the typical sub, with 3 boxes per value track. Both subs are part of the force stalking the USS Kennedy in Scenario 13K (Flattop) and the Yenisey also appears as one of the subs trying to exit in scenario 13M (Convoy Screen).
Zarnitsa (Typhoon class SSBN)This sub appears only in scenario 13H (Boomer) where it is the target. It is hard to detect, with a value of 7, and can easily turn the tables on an attacking SSN with a sensor value of 3 and attack value of +2. It's tougher to sink than usual for a sub, with three boxes on the value tracks.
Oppokov (Improved Typhoon class SSBN)
This is essentially a "Hunt for Red October" style scenario, where the Oppokov is being hunted by Soviet surface ships in scenario 13E (Rebel Without a Cause). It's the same as the Zarnista except for one more "no attack" box on the contact level track, making it very tough for the Soviet surface forces, which are neither numerous nor high-quality.
HMS Valiant (Valiant class SSN)
A good all-around boat, with detection value of 6, a sensor value of 4 and an attack value of +3. The Valiant attacks a Soviet convoy is Scenario 13F (Mounting the Threat) in its only appearance.
HMS Swiftsure (Swiftsure class SSN)
Basically a quieter Valiant, with a detection value of 7, which is fortunate, because it's facing two quiet opponents in the Salta and San Luis in Scenario 13D (Falklands)
HMS Trafalgar (Trafalgar class SSN)The best British boat, it is very hard to detect, with both a high detection value of 7 and an extra "no attack" box on the contact level track. Its 5 senso value means it will quickly achieve a firing solution and its +3 attack gives it a good chance of success when it does attack. This boat is a reinforcement in both of its scenario appearances: 13C (Breakout) and 13I (Sink the Moskva)
USS Baltimore and USS Los Angeles (Los Angeles class SSN)
Dangerous boats, with a 5 sensor and +3 attack making them very potent offensively. They have to be careful, however, as the 6 detection value makes them vulnerable to the better Soviet ships. Both boats appear in 13A (Sub Duel), which is probably the most-played scenario. The LA is also in 13F, 13J and 13M
USS Annapolis and USS Asheville (Improved Los Angeles class SSN)
Much quieter than the earlier boats, with a detection value of 7 and the extra "no attack" box on the contact level. Both boats are stalking the Moskva in scenario 13I (Sink the Moskva). The Asheville is also in 13H (Boomer) and 13J (The Return Home).
USS Seawolf (Seawolf class SSN)
The most powerful sub in the game, with extremely potent offensive ability. It has a sensor value of 6, making most detection attampts close to a sure thing. It fires at a +4, and by special rule it's "swimout" torpedo firing are not subject to passive sonar detection. Defensively it's a 7 with two "no attack" boxes, which makes it as hard to attack as any ship in the game. In Scenario 13C it gets to face three Soviet boats alone, at first. In 13H it's the main nemesis for the Boomer, while in 13J it's the lead gunslinger against the Soviet capital ships.
Nearly all surface ships have detection values of 5, which means they are easy to find. Mitigating that, in the game, is the fact that they share contact information, allowing powerful combined action against subs.
Kiev (Kiev class CVHG)
This powerful ship shows up in just one scenario 13J (The Return Home) where it's essentially a target. Sinking it or the Kirov, below, wins the game for the USA. Although it's a target, it's not a helpless one, and it will be playing a major role in its own defense. Its primary strength is the ability to launch up to four helicopters and keep them in the air with its good endurance number of 2. It's own sensor value of 2 is just passable and its attack value of +1 poor, so it will be relying on the helicopters for its offensive punch. It's a fairly tough ship to sink, with five boxes on the sensor/attack tracks.
Kirov (Kirov class BCGN)
The other target in 13J, The Kirov adds two more potential helicopters with an endurace of 3 and an attack value of +2 to the fleet defense. Being a little easier to sink, with just four hit boxes, it's the likely target of any attack.
Moskva (Moskva class CHG)
Also a target, this time in Scenario 13I (Sink the Moskva), the Moskva is much like the Kiev, except without any attack value of its own, which is a minimal difference, because the Kiev generally won't use its own attack value anyway.
Nikolayev and Tallin (Kara class CG)
Older Soviet escort cruisers, with the ability to launch one endurance-5 helo. Their sensor value is a minimal 1 and they have an attack value of +2. Both ships appear as escorts in 13J while only the Tallin escorts the Moskva in 13I. In neither scenario are the NATO subs likely to waste a shot on them. The Nikolayev may very well be a target in Scenario 13F, however, where it joins the Udaloy and two Victor I class boats in facing two NATO SSNs. If hit, the ship may survive, as it has three hit boxes.
Simferopol and Udaloy (Udaloy class DDG)
The best of the Russian escorts, with a 2 sensor, a 3-endurance helo and an attack value of +2. Both destroyers are part of the force hunting down the Oppokov in 13E, while the Udaloy is also in 13F and 13I.
Neukrotimyy and Revnostnyy (Krivak II FFG)
Small, helicopter-less escorts whose major value is adding another card to the Russian player's hand and a +2 attack platform. Their sensor value is a 1 and they are easy to sink, taking just two hits, although it's probable no one will bother to shoot at them. The Revnostnyy is also part of the force hunting the rengade Oppokov in 13E and appears as an escort with its sister ship in 13I. The Neukrotimyy is also in 13J.
Predanyy (Grisha II class FFL)
This would be the most pitiful surface ship in the game (Sensor 1, Attack +1, One hit to sink) except that it is the only ship that doesn't appear in any of the scenarios. As the game doesn't include any official design-your-own scenario rules, this ship probably doesn't get played much.
HMS Invincible (Invincible class CVH)
The lead ship fighting off a Soviet wolfpack in Scenario 13L (Wolfpack) and the probable main target for the Russians, as sinking her gives them enough points to win instantly. With a mediocre sensor value of 2 and no attack value, the CVH's only real contribution is its three endurance-2 helicopters. It has four hit boxes, so there's a good chance the Russians will have to attack the ship at least twice.
HMS Sheffield (Boxer, Type 22 Batch 2 class DDG)
Its higher detection value of 6 is of little use in the one scenario it appears in (13L) because the Russians will be gunning for the carrier anyway. The ship doesn't add all that much to the task force with its meagre 1 sensor, anemic +1 attack and single endurance-5 helo. Its main value, as a matter of fact, is to beef up the hand size.
HMS Norfolk ( Duke, Type 23 FF)
A good, all-around escort, with a sensor value of 3 and antisub value of +2. It will be taking the lead in many attacks. It also contributes an endurance 3 helo to the task force in Scenario 13L, its only appearance.
USS John F. Kennedy (JFK class CV)Its the target carrier in Scenario 13K (Flattop) but certainly no pushover, able to put up as many as four endurance-2 helicopters. While it has no sensor or attack values of its own, the helos are a formidible force, as long as the weather holds. The toughest ship in the game, it has six boxes in each of its sensor and attack value tracks. While any ship can go down with a "sunk" result, it's probable that multiple successful attacks will be needed to sink the JFK.
USS Virginia ( Virginia class CGN)
In a game that doesn't include any air attacks, this air defense escort is basically just another target. Its sensor value of 2 is nothing special, while its +2 attack is mediocre. It has no helos. The cruiser appears in 13K, as part of the JFK CVBG, where it's not likely to get shot at. But it's also in 13B (Search and Destroy) where it's the main target.
USS Arleigh Burke (Arleigh Burke class DDG)
A good escort, except for the fact it doesn't have a helicopter. It has a better-than-average detection value of 6, a sensor value of 3 and an attack value of +3, making it one of the most dangerous surface combatants. It only appears in Scenario 13M, where it will be dueling with a large force of Soviet subs.
USS Semmes (Charles F. Adams class DDG)
This antique appears as part of the escort of the Invincible. Like the Sheffield, its main value is to increase the British hand size, as it has a lousy sensor value of 1 and a mediocre +2 attack value, with no helicopter.
USS John Rodgers (Spruance class DD)
Probably the best all-around US escort ship, it's quiet (detect 6) and well-eqipped (sensor 3) and carries an endurance-3 helicopter. Only its +2 attack value is disappointing. This workhorse shows up several times. It's in 13G (Turning the Tide); 13K (Flattop) and 13M (Convoy Screen). As a fairly large ship, it has three hit boxes, meaning it will probably survive at least one attack.
USS Simpson and USS Taylor (Oliver Hazard Perry class FFG)
These ships are the mainstay of the NATO escorts. The Simpson is the Virginia's best hope in Scenario 13B, as well as a key part of the escorts in 13G and 13K, along with its sister the Taylor. Quiet (detect 6), well sensored (value 3) and helicopter-equipped (endurance 3) they only have an attack value of +1, so the helo will probably take the lead offensively.
USS Bowen (Knox class FF)
This ship is similar to the Perry-class ships, except for a better attack +2 but less-reliable chopper (endurance 5). The Bowen accompanies the USS Arleigh Burke in Scenario 13M.
Transports. There are three in the game. All three are used in Scenario 13G and 13L. They are purely targets, with no combat values and they do not add to the hand size. Each has four hit boxes, so they will generally need to be hit twice to go down.