American "Perry" class Frigate contrasted to British "Cornwall" Type 22/3 Frigate.

 

I was feeling in an analytically mood. I didn't have the patience to game out an encounter, and found myself wondering what vessel would be "better" between an early model American frigate (I ended up choosing the Perry) and a later build British vessel (which ended up being the Cornwall).

 

I know next to nothing about any warship and saw this as an exercise to contrast some strengths and weaknesses. One of my first problems was how to define "better"? For the sake of this exercise I decided it would come down to "which vessel would I rather be on", or more simply, it became a matter of survivability. However I could see the merit in trying to make a call on which vessel better achieved its stated goal. And so suddenly, instead of comparing stats from my data annexes I found myself at wiki ...

 

The Perry was built as an inexpensive, general purpose escort ship. Originally designed as a specialist anti-submarine ship, the Cornwall developed into a general purpose frigate for use against submarines, other surface ships and aircraft. Soooo both are frigates and general purpose in nature, however I expected the Cornwall to be better suited to ASW and the Perry better in a picket line shooting down incoming missiles.

 

 

Physically

The older (1977) Perry is smaller (2770std) than the 1988 built Cornwall (4280std) but both are considered small and quiet for game purposes. The Cornwall is 1knt faster at 30kts to the Perry 29kts. The difference in size partly accounts for the difference in damage points. 86 damage points for the Perry and 152 for the Cornwall. The 1977 model Perry also is a single shaft so engineering critical hits are doubled. Advantage: Cornwall

 

Sensors

One of my intrigues was comparing an OLDER American ship against a NEWER British one. America is usually seen as being more technologically advanced but in this case there is a "time" handicap since the Cornwall is 11 years younger. I thought this difference would show itself in the quality of sensors. For ease of comparison I will contrast them item by item

 

Perry ACM: 2G towed ECM: 3G Decoy ESM: 3G

Cornwall ACM: 2G towed ECM: 3G Decoy & Jam ESM: 3G

 

Pretty close huh? The only difference being the Cornwall has Jaming electronic countermeasures. Small advantage Cornwall.

 

I also include Radar and sonar under sensors. Looking at Radars first;

 

Perry surface radar 36 32 18 10 6

Cornwall surface radar 41 23 13 7 4

 

Interesting the Cornwall can detect large ships at a greater distance than the Perry, but all other ship sizes the Perry has the smallest advantage.

 

Perry air radar 284 213 159 68 20

Cornwall air radar

 

I am unable to find the Cornwalls Radar 967/968 rader in my data annex (J naval radar)? Any ideas anyone?

 

Sonar

Perry has a hull mounted sonar with an active range of 3.0nm and a passive range of 1.3nm, medium frequency.

Cornwall has a hull mounted sonar with an active range of 4.3nm and a passive range of 2.1nm, medium frequency.

 

The difference in ranges doesn't appear much. However when hunting (or being hunted!) by a submarine, the ranges are "close", and the way H4.1 rules work with 25%/50%75% detection percentages, range differences are critical.

 

For example lets look at both units trying to detect the same very quiet soviet submarine travelling at 5kts.

Perry 25% chance at 2.3nm 50% chance at 1.7nm 75% chance at 0.6nm

Cornwall 25% chance at 3.2nm 50% chance at 2.4nm 75% chance at 0.9nm

 

The ranges still look close, hardly worth it. But a submarine travelling at 5kts moves 0.25nm in a 3 minute tactical turn. Both ships trying to detect the sub with range closing by 0.25nm per tactical turn looks like this.

 

Turn Range Perry Cornwall

1 3.2nm 0% 25%

2 2.95nm 0% 25%

3: 2.7nm 0% 25%

4 2.45nm 0% 25% by the barest of margins (50% kicks in at 2.40nm)

5 2.20nm 25% 50%

 

I think this simple table shows despite how close the sonars look, the impact is huge. The Cornwall gets 4 tactical turns to detect a submarine at 25% while the Perry has no chance at all. At a range of 2.2nm the Perry finally gets the chance to detect the sub at 25%, while by now the Cornwall has a 50% chance.

 

The Cornwall was advertised as a specialist an anti-submarine unit, comparing their sonars i feel this is Advantage Cornwall.

 

 

I've ruled a line at the year 1988. Thats when the Cornwall first came out. So thats the basis of this comparison. The Cornwall is the third edition of the Type 22 (Broadsword 22/1, Boxer 22/2 and Cornwall 22/3) so it is the most advanced. Ruling a line at 1988 means many of the improvements made to the Perry don't come into play. Is that fair? Well, the aim of this exercise was too compare an old model against a brand new model. The Perry did receive many improvements post 1988 but then we'd be comparing a new Cornwall against a re-fitted Perry and we'd be missing the point. So 1988 it is.

 

3. Weapons

Defence first.

The Perry has a single barrel 76mm air defence gun that covers the port and starboard side. Range is 3.5nm and close/long probability hit numbers of 40% and 25%.

The Cornwall has two LS-30B 30mm air defence guns, one covering port side, the other starboard each under local control (sea skimmer capable). Range 1.6nm and close/long range hit numbers of 15% and 5%.

 

It looks like the Perry has twin advantages of range and hit probability. But there is more information contained in the comments. The Perry is not sea skimmer capable, so must halve to hit numbers against sea skimmers while the Cornwalls 30mm is under local control and so it is SS capable. After taking this into account, "to hit" numbers are pretty close. Perry is still marginally in front due to its longer range (possibly preventing air burst if a missile is engaged at close range).

 

Also the Cornwall has small magazines and is manually loaded. Manual loading is covered at 5.2 "assume it takes 2 tactical turns (instead of automatically being reloaded in the next engagement turn) to reload". I have not been able to find a section detailing the impact of small magazines.

 

My take is, against non-SS targets its advantage Perry (range, probability to hit, reloading time). Against SS targets it is small advantage Perry (range, reload time, almost equal probability to hit). The only advantage the Cornwall has is it is able to engage two targets are a single time rather than one. In my mind this is cancelled out by the slower reload times.

 

Air defence guns: Advantage Perry

 

In 1988 both units had air defence missiles.

Perry has a single forward facing SM1MR Block IV/V. Air range 25.0nm, second generation, ATA of 4.5. ROF = 3

Cornwall has forward and aft Sea Wolf. Air range 2.7nm, second generation, ATA of 5.0. ROF = 4 See skimmer capable.

 

I'd have to say advantage Cornwall here. Slightly higher ROF, but more importantly being SSC is the advantage. As with the 30mm gun, the Cornwall has to manually load the Sea Wolfs. The Cornwall has 12 Sea Wolves loaded at a single time. So I do not see the manual loading being as large an issue as it was for the air defence gun. 12 Sea Wolves with a ROF of 4 means 3 salvos have been fired before reloading is required, at that point it may become an issue, but given modern day engagements, the engagement may well be over one way or the other by then anyway. The Perrys advantage is range of 25.0nm but i do not see it being enough to outweigh Cornwalls sea skimmer capability and slightly higher ROF. Advantage Cornwall.

 

Overall advantage is hard to say. In the short term i think the Cornwall is better able to defend itself in the first round or two before reloading is required. While I feel like the Perry would hold up better under a sustained attack over a number of minutes since its able to reload faster. Even.

 

 

Offensive capability

The Perry has its 76mm gun with surface range 7nm and close/long probability hit numbers of 65% and 33% doing 12 or 3 points of damage.

It also has SM1MR Block IV/V with a surface range of 25nm doing 5 points of damage, ROF = 3.

 

The Cornwall has 114mm gun with surface range of 12nm and close/long probability hit numbers of 65% and 33% doing 8 or 2 points of damage.

The Cornwalls Sea Wolfs cannot engage surface targets.

 

The surface guns are even, the Perrys SM1 gives it a slight advantage which might have been more if it didn't do so little damage (5 points). Small advantage so far to the Perry.

 

The Perry has 6 torpedo tubes and 3rd generation Mk 46 torpedos with a range of 6.0nm moving at 45kts doing 11 points of damage against submarines only.

The Cornwall has 6 torpedo tubes and 3rd generation Stingray torpedos with a range of 4.3nm moving at 35kts doing 23 points of damage against submarines only.

 

Which do you value more? Mk 46 range and speed or the singrays extra damage? Even? I'm leaning towards declaring the Cornwall better simply because it has the better sonar, and therefore its more likely to be in a position to use its torpedoes. But then i think the short range of the Stingrays mean it will need to be really close to an enemy submarine to be in effective range. I'm going to declare this even, unless anyone can mount an argument for either unit.

 

Both ships have 2 x helicopters. I have not looked at helicopters. And while I know they are vital in the anti-submarine role I'm going to rule this even.

 

 

Overall

 

1. Physical advantage Cornwall

2. Sensors small advantage Cornwall. Radar incomplete. Sonar, advantage Cornwall

3. Weapons. Air defence guns advantage Perry. Air defence missiles advantage Cornwall. Anti-surface ability small advantage Perry. Torpedoes even. Helicopters even.

4. Overall its feeling like the Cornwall comes out on top. The Perry has an advantage in guns (anti-air and ship). However the Cornwall has advantages in all the other areas (exempting ties). The biggest argument for me is the Cornwall being able to take almost twice as much damage as the Perry before sinking. The Cornwall wins easily in this regard and accumulates most of the other advantages as well.

 

The Perry is billed as an all round escort. It is well rounded in regards to electronic, acoustic and ESM sensors, and its weapon systems. While i knew nothing about either ship prior to this I expected the Perry to be better suited in a picket line, and this proves correct (Cornwalls slower manual loading and small magazines being negatives in this role).

 

The Cornwalls main task is anti-submarine and it wins out over the Perry (as expected). And it might also be better rounded overall than the Perry.

 

I'd pick the Cornwall, the more modern ship. If you allow upgrades to the Perry to be included in later years the situation might change (harpoons!).

 

This exercise took a good couple of hours. Starting from zero I have learnt about two similar vassals. Vital information can be found in "remarks" or "comments" to help differentiate between units. I hope the write up has been useful/interesting. I think more value would be gained if the units being compared were pitted against one another (ie NATO v Soviet). Feel free to correct me in any areas or make your own judgements using your own rational.

 

 

 

 

TO FOLLOW SHORTLY

1. Physical comparison

2. Sensors

3. Weapons

4. Final call

I'm looking forward to your analysis. You touch upon a very important point by questioning the definition of 'better'.

 

An oft-cited criticism of the Perrys is that they have only one propeller shaft vs the Type 22/3 that has dual shafts.

 

On the ASW front I would expect the Perry to be very capable with its towed array and dual helicopters. Frankly I wouldn't want to be on the Perry if SSMs were headed my way since I would have been considered an expendable picket/missile sponge with little real air defense capability.

Yes, interesting focus of the question ...

I call Perrys Overhead Projectors, because they're about as much as one.

Hey, thanks for the comments.

Main post updated. Fingers crossed another slow day at work and i can finish this off.

 

Next, i hope to do a similar comparison of a NATO v Soviet unit that may have gone head to head.

 

Well done TonyE about the Perrys single screw ... i had picked it up in the Perrys notes of my data annex (double engineering critical hits) and hoped it would be a surprise to people! Still, i'm happy that the game is able to take the real life issue into account somehow, it lends credability to the rules and makes each unit unique rather than each cardboard ship being the same as the next.

 

I'm sure the issue of "best" and how to define a "winner" will come up again when i get to the end and am able to take everything into account. I'm sure others reading this may have their own views also.

 

I wonder what the split is here between USA and European based posters? And if nationality will colour anyones thinking?

Next, i hope to do a similar comparison of a NATO v Soviet unit that may have gone head to head.

 

I wonder what the split is here between USA and European based posters? And if nationality will colour anyones thinking?

 

Or examine the Cornwall vs the current Australian Perrys .

 

My experience here is that nationality does color the thinking of our astute members and not always in the expected way. Seems we all agree the Perrys aren't invincible warships without peer. There might be more non-USA members willing to defend them than USA members. I look at a Burke or a Tico and think the Perry is awful but it isn't just a question of overall capability, it is that eternal balance of capability, cost, and training.

I am unable to find the Cornwalls Radar 967/968 rader in my data annex (J naval radar)? Any ideas anyone?

 

Country System Function Perf (nm) RCS (dbsm) BPV RCS Rng vs. Lge PRF Rng (nm) Max PV Clutter ECCM Gen # Large Medium Small VSmall Stealthy Mod IOC Remarks

 

UK Radar 967/968 AS 50 5 63.0 18 106 Inst 150 87.0 20 10 106 74 53 21 6 1979 Paired back-to-back antennas

 

UK Radar 967/968 SS 18 45 5.2 62 48 Inst 50 68.0 10 0 48 27 15 9 5

 

 

From June 2011 annexes (sorry about the ugly format.

Just realised i missed "sonars" under the sensors write up. I'll adress it tonight when i put the next update up.

About the surface search radar ranges:

The American ships are usually taller ships and have bigger masts.

You can constate it with good profile drawings of the ships and a ruler (I do it from years ago from DB editing ...), to obtain the height about the sea of the SS radar antenna (or of a concrete lookout post in older ships and DBs, without radar).

As result of my old meditions, the Perry is a taller ship (in the DB Mast Ht: Large Ship (40 m)), and the Type 22/3 Cornwall is a shorter ship (in the DB Mast Ht: Medium Ship (29 m)).

As consequence, and using the paper rules (4.2.2.2.) as basis and reflected in the game engine of the computer game but with other range values, the Perry can "see" with the surface search radar the Cornwall at a maximum of 27 nm range (maximum radar horizon for a ship with Large mast), and the Cornwall can "see" the Perry at only a 16 nm range (maximum radar horizon for a ship with Medium mast)

(I'm not sure on this moment of the 16 nm range value in the Game Engine, but we can do some testing later).

Full discussion up.

Nice comparison!

 

ASW

Stingray is actually 4.3 nm at 45 knots. Don't forget to look at Maximum Depth and Remarks for torpedoes.

Stingray max depth is Deep III, Mk46 series is Int V.

Stingray has DE warhead, Mk56 Mod 5A(S) is Shallow Water capable.

 

Cornwall has Sonar 2031 towed array, OHP has SQR-18 or SQR-19 towed array also.

 

If a scenario takes place in shallow water, sonar frequencies are also important. Lower frequency sets are 1/2ed in shallow water, have no CZ, etc.

 

 

Air Defence

If its a mid-Atlantic scenario against Soviet bombers, OHP has a longer ranged AS radar and can contribute to shooting down a High altitude stream of AS-4 or AS-6 missiles.

Cornwall has improved sea defence against seas skimming missiles - but cannot contribute to area air defence.