The DF rating for ships

[Curtis Lemay]

ORIGINAL: Lobster

The Titanic displaced 52k tons and had a crew of about 1000. The Warspite displace 32k tons and had a crew of about 1000. The Titanic would not have been more durable than the Warspite, it had no armor. Except in TOAW. Could be displacement does not equal durability? Just a thought.

Right. Being a merchant vessel, WitP recognized that such would have less durability per displacement than warships. Armor is independent of durability, though. Also note that the Titanic's compartmentalization was not water tight - which is why she's on the bottom.

Crew was mostly stewards and such. Not quite like a warship's crew.

BTW, is it possible to have critical hits? As in the Hood.

Already there.

[Lobster]

ORIGINAL: Curtis Lemay

If ship-to-ship combat is going to be by missile, and ships now have missile defense systems...isn't that about the same as armor was to gunnery? So, one way to model that might be as armor. [:D]

Oh oh. This made me think about land based anti projectile systems developed from the Phalanx. Works against mortars and artillery too. Can engage ground targets to defeat nape of the earth targets. Range is limited but they are point defense systems. But they would be deadly against incoming.

[cathar1244]

The Titanic displaced 52k tons and had a crew of about 1000. The Warspite displace 32k tons and had a crew of about 1000. The Titanic would not have been more durable than the Warspite, it had no armor. Except in TOAW. Could be displacement does not equal durability? Just a thought.

Warships and merchantmen are calculated differently.

Per the calcs above for a rough durability rating, Warspite at 32k tons would come in at "128" and the Titanic (rated as a merchantman) would come in at "104".

"Rough" the calc is as it does not look at things like crew training, fire suppression systems, and so forth. Or, in my example using the Sheffield, something like construction using aluminum that burned when hit with the Exocet missile.

As TOAW provides a limited set of ship characteristics, some of this will have to be WAG'd by scenario designers. As Curtis pointed out, one could look at a close-in defense system as a form of armor. Something like that is tough to assess with readily available sources.

Cheers

[Lobster]

The Phalanx has had a few miscues. One report I read was where it was supposed to target incoming missiles but instead fired on the defensive chaff released by another ship, hitting the other ship. I do believe the incoming missiles were destroyed by anti missile missiles fired by a third ship.

The ground based Phalanx makes an attempt at reducing collateral damage by tracer limited rounds. Maybe another mechanism also. But not so the naval model. Been awhile since I read all of this since I don't care too much for how TOAW models modern warfare so I don't recall all of the specifics.

[Lobster]

The Titanic did have watertight bulkheads. Oh, and there were no fires or explosive damage. Unfortunately the extent of the damage extending across several of them resulted in flooding beyond what it was designed to mitigate. Four and it survives. More than that and it sinks. Even a warship would be hard pressed to handle damage across such a broad area of the hull. Also, unfortunately, the damage was all at the bow causing the flooding to sink the ship by the bow overflowing the bulkheads. Perhaps if it had been amidships it would have still survived six ruptured watertight bulkheads.



But this is all blah blah blah. I still have reservations about tying how tough a ship is by how much it weighs.

[cathar1244]

The ship ratings spreadsheet is interesting in terms of this discussion.

A "Fletcher" class destroyer has a durability that suggests it was calculated from the displacement divided by 250 (warship).

An older "Paulding" class destroyer, by comparison, suggests it was calculated from the displacement divided by 350 ('navalized'). Why? No idea, although one might assume that ship design for destroyers advanced between the World Wars. The Paulding also had far less displacement, so perhaps less survivable in terms of bulk.

Cheers

[cathar1244]

Some commentary on the close-in systems versus projectiles.

Could a modern destroyer intercept an incoming shell, such as a 14 inch, with a CWIS Phalanx or other modern, computer operated system?
Yes. The CIWS, or it’s land based CRAM version, can intercept and destroy projectiles far smaller than a battleship main battery projectile. The only real issue with the battleship round would be if it was a standard base fuzed armor piercing round. In such a round there is a quite small bursting charge and a very thick steel casing and nosecap. the CIWS operates by hitting the inbound round with either 20mm slugs or a 15mm sabot projectile and detonating the bursting charge. With the very thick skinned AP round and extremely rugged, base-mounted fuze, that might be difficult.

With “high capacity” battleship rounds, it’s a much different story. Furthermore, these are far more likely the round of choice for a battleship to fire at a modern, “thin skinned” destroyer. The casing is MUCH thinner that a classic heavy naval round and the fuze is more often nose mounted. Hit the fuze or penetrate the casing and the bursting charge will detonate. The warheads on the ASCMs that were the design target for CIWS are often “semi-armor piercing” and intermediate in difficulty between the AP and ““high cap” battleship rounds.

But this brings us to the real and abiding problem with a CIWS defending against a battleship projectile. Even if the inbound round is detonated a couple of thousand feet away from the destroyer, you still have a couple of thousand pounds of hot steel shards headed for the destroyer at high velocity. That’s almost certainly better than a hit on the destroyer with a high capacity round, but an aegis radar face would not fare well against the shower of fragments.

Cheers

[Lobster]

Not much to worry about. Not many battleships around. [;)]

But this does point out why the Japs had such a problem with Taffy 3. They thought they were engaging capital ships so were using armor piercing rounds that went right through the destroyers and destroyer escorts. [:D]

Which again raises the question, should durability be tied to tonnage?

All hail Taffy 3. [&o]

[Curtis Lemay]

In an age of anti-ship missiles, how would a BB (or any other gunnery platform) get close enough to use its guns?

[Curtis Lemay]

ORIGINAL: Lobster

The Titanic did have watertight bulkheads.

Not from the top.

[Lobster]

ORIGINAL: Curtis Lemay

ORIGINAL: Lobster

The Titanic did have watertight bulkheads.

Not from the top.

I already mentioned that:

ORIGINAL: Lobster
Also, unfortunately, the damage was all at the bow causing the flooding to sink the ship by the bow overflowing the bulkheads.

[Lobster]

Not all of Warspite's bulkheads go to the top deck. But that's not the issue. In any event we all know nothing will change don't we. [;)]

[Lobster]

A sad day for a fine ship.

[cathar1244]

Interesting bit from the hazegrey site.

During the Falklands War, SHEFFIELD was hit by an Argentine Exocet missile which among other things disabled the fire fighting mains, and although the fires were put out she sank under tow several days later. COVENTRY was sunk by Argentine bombs during the same campaign. The oft repeated story about the loss of these ships due to the use of aluminum in their superstructures is a myth.

The question of armor representation for modern ships is not straightforward. If the one quote about a CIWS being able to stop incoming shells is correct, then one could go to an extreme and give the modern ships armor such that it could withstand a strike from a 16-inch cannon.

That would not be a good representation. What the Falklands War brings out is that modern ships are fragile. When too many threats emerged for the ship to counter, the damage took them out of action.

Seems like straits and narrows would offer shore based guns an opportunity to engage modern ships. Not sure about today, but the Warsaw Pact countries had 130mm batteries to defend the Baltic coastline during the Cold War.

Cheers

[Lobster]

In the 1970s several batteries were installed near Vladivostok to protect against the Chinese. If I recall there were Soviet coastal guns active somewhere in the Baltic/Gulf of Finland.

Also, see Battle of the Dalmatia Channels.