Matrix Games Forums

Noting the revision to deck armor re carriers as a concept

and noting what we learned about inconsistent durability ratings re carrier data

I am wondering if

a) we might not want to try to re rate side armor to account for vast differences between ships

b) we might not want to insure gunship durability is done to a consistent standard (as auxiliaries are and carriers are)?
which - in the process - might also be affected by an adjustment to a similar to what we did with deck armor

The deal is this: USN "all or nothing" armor - and IJN Yamato "box armor" - weigh a lot - and provide uniform protection to a vast vital area including engines and magazines and steering gear -

but many ships have minimal protection - say only for steering gear or magazines -

and most have vast variations in the side armor - tapering toward the ends and also tapering vertically

So the "maximum thickness" standard is applied wether this is just 1 per cent of the target area (steering gear) or 50 per cent or more (all or nothing).

The reason WITP modeled this way is the complexity of modeling anything else is vast. We would need a formula to figure out a consistent standard. There would be several factors -

1) are engines protected?

2) are magazines protected - and to the same standard?

3) is steering gear protected - and to the same standard?

4) is the side armor uniform - or tapered - and to what extent?

5) What is the impact of variations from a true box?

6) is there "end enclosure" armor? (transverse bulkheads) and is it the same as side standard?

7) What about vertical height?

This might be like aircraft maneuverability - hard to come up with.

The main thing that determined how many hits were needed to sink a ship (in the absence of protection) was waterline area, with subdivision limiting the area flooded or destroyed by a given hit. Protection then determined whether a hit was actually effective. Underwater hits generally had twice the effect of the same amount of explosive delivered by bombs or shells. The area destroyed by a hit scaled as the 2/3 power of the warhead weight. Carriers and tankers were very vulnerable to burnout, and all warships were vulnerable to magazine explosions. Japanese cruisers had large torpedo warheads to worry about, too.

Yes that is a big problem.

First - you need to know how WITP system works. For example does the game simulates frontal hits when some TF crosses the T of another?

Second - find what are the chances of an hit in diverse places.

Third - find detailed data about every ship armor. There are several ships that are very good at close distance and poor at medium or long distance.

Fourth - build a "belt" armor rating knowing that it also works for Torpedo hits.


It is even worse for CL's since there are many variations.

The WITP system is more or less semi-abstracted. Instead of a detail model - where is a very crude model - and "die rolls" are used to simulate a range of possible outcomes. If there were more factors under consideration - there would be more fields which contained the data involved. However - I must say that the fundamental system is far better than I would have expected possible - on theoretical grounds. Coming from a world in which about an order of magnitude more fields are used - I am more than a little impressed at how well the outcomes work most of the time.

Since we can not change the system at its core - what we do is result oriented programming. We have been able to add a number of things not intended by GG when the design was done - and I think we can do that again here. His system considers durability and the maximum thickness of armor of at least two types (apparently tower armor is not actually related to any sort of damge - although it is related to reports). It is not clear if armor has any impact on underwater attacks - but clearly durability does.

Sometimes we (in RHS anyway) use "CL" (or other warship designations including CA, DM, DMS) for the effects we get when code sees them (permitting some missions, responding more aggressively as is appropriate for some vessels - say a raider - or the ability to lay or sweep mines) without regard for the fact these vessels have no armor. And indeed some AMC and CML didn't have any armor IRL as well. Then too there is the peculiar case of "micro cruisers" in USN - ocean going, six inch gun armed, also armored "gunboats" - a wierd case if ever there was one. I think this works out well in all variations because of the presence of armor fields we can enter zero in if appropriate. Whatever armor would do for a "real" cruiser - it does not do it when it isn't there.

First pass algorithm:

assume a cruiser (battleship, name it) has about 25 per cent of length devoted to engines, 5 per cent to magazines, 5 per cent to areas involving neither forward of those, and 5 percent aft = 40 per cent. If we want to have some room in our formula for "ends" - we might rate the after "end" at = 5 per cent of length - the fore end at 4 per cent - and steering gear at 1 per cent. This brings the total to a convenient 50 - so we can double all the factors to get 100 per cent.

Now - the base case is an "all or nothing" ship with uniform armor over all the surfaces under consideration. In that case we will keep maximum armor thickness as it now is - so 100 per cent times maximum side armor = current side armor. BUT we have a way to calculate all the other cases:

For the contribution of side armor over engineering spaces - use 50 per cent of the armor in mm.

for the contribution of side armor over the magazines - use 10 per cent of the armor in mm.

for the contribution of side armor which is bigger than just engineering and magazines - we have two cases - fore and aft - use 10 per cent of the value. IF it is the same - use the same value. IF the armor thins - use 20 per cent of the thin value (or 10 per cent fore plus 10 per cent aft if in some case they were different).

for the contribution of "ends" - transverse bulkheads - use 10 per cent of the aft armored bulkhead and 8 per cent of the forward one -

and for the contribution of steering gear protection - use 2 per cent of the thickness.

Add all these up - and you have a composite value.

Second pass algorithm correction:

What if armor is in more than one layer?

The new side armor = 100 per cent of the thickest layer plus half of the sum of all other layers.

First pass durability algorithm:

use standard displacement divided by X

where x = 400 (apparent WITP base value)

or x = 333 (value now used for carriers derived from CHS values for Akagi and Kaga)

or x = 200 (used by auxiliary ships with naval damage control systems and parties)

Second pass durability correction factors:

1) If the ship is bulged - add 10 per cent

2) If the ship has extraordinary damage control - e.g. Prinz Eugen type remote controlled watertight doors - add 10 per cent

3) If the ship is armored - add half the difference between maximum side armor and the new adjusted side armor

4) If the ship is Japanese - subtract 10 per cent

ORIGINAL: el cid again

First pass durability algorithm:

use standard displacement divided by X

where x = 400 (apparent WITP base value)

or x = 333 (value now used for carriers derived from CHS values for Akagi and Kaga)

or x = 200 (used by auxiliary ships with naval damage control systems and parties)

That looks backwards.

Shallow draft should increase durability, while deep draft should decrease it.

ORIGINAL: el cid again

Second pass durability correction factors:

1) If the ship is bulged - add 10 per cent

2) If the ship has extraordinary damage control - e.g. Prinz Eugen type remote controlled watertight doors - add 10 per cent

3) If the ship is armored - add half the difference between maximum side armor and the new adjusted side armor

4) If the ship is Japanese - subtract 10 per cent

Date of construction was very important, affecting compartmentation, torpedo resistance, and simple care in detailed design. WWI warships were about twice as vulnerable to torpedo damage as WWII designs.

There is also the issue of steel quality.

ORIGINAL: Dili

There is also the issue of steel quality.

That was relatively marginal (+/-10%)

ORIGINAL: herwin

ORIGINAL: el cid again

First pass durability algorithm:

use standard displacement divided by X

where x = 400 (apparent WITP base value)

or x = 333 (value now used for carriers derived from CHS values for Akagi and Kaga)

or x = 200 (used by auxiliary ships with naval damage control systems and parties)

That looks backwards.

Shallow draft should increase durability, while deep draft should decrease it.

First - this is the foundation of WITP design theory - ship durability is mainly a function of size - and the primary question if we want standardized data (instead of data all over the dart board from many inputters) is what is x?

Second - this is correct in naval theory. I was required to go to damage control school - in spite of it not being my rating - after a terrible accident on a carrier (USS Forrestall???) which killed about 120 pilots - because NON damage controlmen didn't know what to do. I scored 100 per cent on both practical and written tests (unfortunatly) and earned the unique "gold certificate" which only can be awarded to one person. Another sailor also scored perfectly - unusual - and the school decided I got the certificate because he was a senior damage controlman - so it "must be harder for another rating to do it." Anyway - the main reason a ship sinks is it loses the ability to float. [It can be a mission kill - weapons and electronics and cargo burned out or rendered useless by this or that - but it is not lost until it sinks] In naval DC we define things in terms of "full load displacement" because - when the total weight of a ship = full load displacement - the ship sinks. Now for various reasons - not mainly damage control related - standard displacement is more related to "how much stuff makes up the ship"? The full load is that plus the fuel, boiler feedwater, lube oil, ammunition and cargo. One might argue we should use full load vice standard - but full load data is not available for many ships - and standard is. Since cost to build is more related to standard - it is a compromise and it is pretty good.

Anyway - a ship IS harder to sink as its sheer volume increases. This may or may not be related to draft - it usually is - but need not always be. Some large ships have shallow drafts for various reasons - but in all cases - when total weight of hull and stuff in the hull = full load - the ship sinks - regardless of draft.

I am not sure why deep draft makes a ship more vulnerable in your view? I assume it makes it more likely to hit a mine, or be hit by a torpedo, but while that is true it does not directly affect us here. That should be addressed in the weapons routines - and either it is or it can be some day. I am pretty sure it is easier to hit a large target - the data seems to support that - and that is true even if one is using shells or bombs. A bigger target should mean more hits. And that should result in easier sinking. But it is not strictly related to draft.

ORIGINAL: herwin

ORIGINAL: el cid again

Second pass durability correction factors:

1) If the ship is bulged - add 10 per cent

2) If the ship has extraordinary damage control - e.g. Prinz Eugen type remote controlled watertight doors - add 10 per cent

3) If the ship is armored - add half the difference between maximum side armor and the new adjusted side armor

4) If the ship is Japanese - subtract 10 per cent

Date of construction was very important, affecting compartmentation, torpedo resistance, and simple care in detailed design. WWI warships were about twice as vulnerable to torpedo damage as WWII designs.

This could be a factor. In more complex models I consider the quality of compartmentation - but here I only considered the extreme cases (German being a plus, Japanese being a minus). We could make WWI era ships a minus factor too. But the chance of sinking is not proportional to durability - the smaller the durability the chance of sinking rises far greater than linear proportion. A smaller value is more likely to be overwhelmed - a larger one may reach port and stay afloat long enough to repair.

ORIGINAL: Dili

There is also the issue of steel quality.

Well - is there any possibility of getting such data for all ships? can you provide a rule of thumb that is reasonable? Otherwise it is moot.
No data = we cannot consider it.

IF we could get or assume reasonable data - what would the impact be?
I hate to say this - but armor is not all the same either. We probably cannot get into this kind and that kind - and the data would take a decade to assemble even if available - which it probably is not for the whole set.
But tell me what you have in mind - how to get the information needed without taking a lifetime - and how to apply it if we did get it?

ORIGINAL: el cid again

ORIGINAL: herwin

ORIGINAL: el cid again

First pass durability algorithm:

use standard displacement divided by X

where x = 400 (apparent WITP base value)

or x = 333 (value now used for carriers derived from CHS values for Akagi and Kaga)

or x = 200 (used by auxiliary ships with naval damage control systems and parties)

That looks backwards.

Shallow draft should increase durability, while deep draft should decrease it.

First - this is the foundation of WITP design theory - ship durability is mainly a function of size - and the primary question if we want standardized data (instead of data all over the dart board from many inputters) is what is x?

Second - this is correct in naval theory. I was required to go to damage control school - in spite of it not being my rating - after a terrible accident on a carrier (USS Forrestall???) which killed about 120 pilots - because NON damage controlmen didn't know what to do. I scored 100 per cent on both practical and written tests (unfortunatly) and earned the unique "gold certificate" which only can be awarded to one person. Another sailor also scored perfectly - unusual - and the school decided I got the certificate because he was a senior damage controlman - so it "must be harder for another rating to do it." Anyway - the main reason a ship sinks is it loses the ability to float. [It can be a mission kill - weapons and electronics and cargo burned out or rendered useless by this or that - but it is not lost until it sinks] In naval DC we define things in terms of "full load displacement" because - when the total weight of a ship = full load displacement - the ship sinks. Now for various reasons - not mainly damage control related - standard displacement is more related to "how much stuff makes up the ship"? The full load is that plus the fuel, boiler feedwater, lube oil, ammunition and cargo. One might argue we should use full load vice standard - but full load data is not available for many ships - and standard is. Since cost to build is more related to standard - it is a compromise and it is pretty good.

Anyway - a ship IS harder to sink as its sheer volume increases. This may or may not be related to draft - it usually is - but need not always be. Some large ships have shallow drafts for various reasons - but in all cases - when total weight of hull and stuff in the hull = full load - the ship sinks - regardless of draft.

I am not sure why deep draft makes a ship more vulnerable in your view? I assume it makes it more likely to hit a mine, or be hit by a torpedo, but while that is true it does not directly affect us here. That should be addressed in the weapons routines - and either it is or it can be some day. I am pretty sure it is easier to hit a large target - the data seems to support that - and that is true even if one is using shells or bombs. A bigger target should mean more hits. And that should result in easier sinking. But it is not strictly related to draft.

This comes from an OR study I was involved in about 30 years ago where we investigated the detailed effect of various hits. While it is full load displacement that is overwhelmed when the ship sinks, the resistance of the ship structure to floatation damage is much more pronounced in the horizontal directions than it is in the vertical direction.

ORIGINAL: el cid again

ORIGINAL: Dili

There is also the issue of steel quality.

Well - is there any possibility of getting such data for all ships? can you provide a rule of thumb that is reasonable? Otherwise it is moot.
No data = we cannot consider it.

IF we could get or assume reasonable data - what would the impact be?
I hate to say this - but armor is not all the same either. We probably cannot get into this kind and that kind - and the data would take a decade to assemble even if available - which it probably is not for the whole set.
But tell me what you have in mind - how to get the information needed without taking a lifetime - and how to apply it if we did get it?

NO has the data. It's basically a national parameter. Like I wrote, marginal.

ORIGINAL: el cid again

ORIGINAL: herwin

ORIGINAL: el cid again

Second pass durability correction factors:

1) If the ship is bulged - add 10 per cent

2) If the ship has extraordinary damage control - e.g. Prinz Eugen type remote controlled watertight doors - add 10 per cent

3) If the ship is armored - add half the difference between maximum side armor and the new adjusted side armor

4) If the ship is Japanese - subtract 10 per cent

Date of construction was very important, affecting compartmentation, torpedo resistance, and simple care in detailed design. WWI warships were about twice as vulnerable to torpedo damage as WWII designs.

This could be a factor. In more complex models I consider the quality of compartmentation - but here I only considered the extreme cases (German being a plus, Japanese being a minus). We could make WWI era ships a minus factor too. But the chance of sinking is not proportional to durability - the smaller the durability the chance of sinking rises far greater than linear proportion. A smaller value is more likely to be overwhelmed - a larger one may reach port and stay afloat long enough to repair.

This was a biggy, at least in the statistics. There was a lot of development between WWI and WWII. The three major categories I identified were ships designed before they really understood the danger of torpedoes (i.e., designed to about 1916 or so), ships designed to be resistant to torpedo damage (post war), and carriers (for some reason, probably involving large open spaces in the design). If a WWI ship could absorb 2 torpedoes before sinking, a WWII ship could absorb 4 and a carrier could absorb 3.

Some data here:

http://www.navweaps.com/index_nathan/metalprp2002.htm

Index link:

http://www.navweaps.com/index_nathan/index_nathan.htm

ORIGINAL: Dili

Some data here:

http://www.navweaps.com/index_nathan/metalprp2002.htm

Index link:

http://www.navweaps.com/index_nathan/index_nathan.htm

Yes, when I refer to NO, that's him. I did German to English translations of some of that stuff for him about 30 years ago.