"How a warship's weight breaks down?" Topic

Tinkering with some ideas for rules and found myself wondering how a ships mass breaks down. Since my physical library doesn't really stretch to this kind of thing I hit the internet and turned up the detail I was looking for on a grand total of one ship. HMS Hood, which apparently broke down as approximately 70% for hull and armour, machinery 13% and armament approximately 13%. Seems reasonable, but can anyone point me at sources of other vessels, particularly other classes?

Siegfried Breyer's Battleships and Battlecruisers, 1905-1970 does a pretty good job of this.

Conway's 1905-1921 and 1922-45 books are also useful. Remember
"Hood" was a WW I battlecruiser design.

Conway's are great but they really do not give the kind of breakdown that Breyer's does for most (but not all) classes. For example, Breyer lists

Hull, auxiliary machinery and equipment – 31.4%
Armor – 39.9%
Weapons – 23.2 %
Engines – 5.5%

for the North Carolina Class. Conways does not get into this. Never-the-less they are great for a stinkload of other details.

Note that when comparing WW2 ships of different nationalities that weight categories differed from country to country, making direct comparisons difficult. For example, I recall that the US and the UK differed on the definitions of at least some of the following categories: "hull", "armament", "armor", and "machinery".

Don't know if Breyer took this into account.

MH

Problems begin to arise when the armour is part of the strength structure of the hull. Is it part of the weight allocated to armour or is it included in the hull weight?

I'm sure that a David Mankey will be able to give a more detailed answer.

I'm curious as to how you would make use of this information (even if it were fully available and compatible between different navies). Perhaps you could tell us something about the rules you mentioned and why this weight distribution might be useful, please?

For US ships, Norman Polmar's design studies are very useful.

Mr Polmar's books are very good but Norman Friedman's Illustrated Design History series on US battleships, cruisers, destroyers, carriers, submarines, small combatants cover the ships in great detail link

Thanks guys. In lieu of a (free) online source I may well shelve my thoughts on this subject. Since extending my library to cover this looks like a seriously expensive proposition. I got lucky recently with a copy of Jane's 1906-1907 reprint on eBay and I really wish I'd picked up the WWII re-print when I saw it in a remaindered book store years ago for a few quid – I did get the WWI version. Clearly issues of classification and definition will make a neat unified dataset nigh on impossible, but at least initially I was just trying to get some indicative numbers.

As for the rules it initially started with thinking about using GW's old Space Fleet rules for pre-dreadnoughts and then kind of drifted into old school floatation box damage tracks and whether I could do something clever with that merging the boxes and hit location for a simple fast play game.

Rules-wise it might be worth looking at the General Quarter series, if you haven't already. GQ3 is more granular than GQ1&2, but both use combined flotation/speed damage tracks.

Hi ROUWetPatchBehindTheSofa,
Here is a suggestion. If you are looking to determine ship survivability, I suggest that you ignore displacement; displacement represents only what is already underwater. Consider "Reserve Buoyancy" as the determining factor. Speaking in very broad terms, reserve buoyancy = the areal plan-form of the ship x freeboard x ~0.65 (permeability factor). That will approximate (once again in broad terms) the volume of flooding necessary to eliminate the ship's positive buoyancy (i.e. – sink it). "Permeability Factor" = the percentage of internal volume not otherwise occupied by equipment. stores, etc. I consider a loss of 50pct of reserve buoyancy as an abandon ship trigger due to loss of stability. Ships rarely sank without first having first either capsized or reached the point of no return on their transverse stability curve.

FWIW, this approach works very nicely for my WW1 rules, right across the entire spectrum of vessel sizes.

- – -

BTW, do not trust the ballistic data which appear in Jane's or Brassey or Weyer. Their relationship to reality is, one might say, "tenuous".

B

Blutarski….In the use of reserve buoyancy, More info please…. Do you figure RB for the ship and assign blocks of: X amt per block, to each ship? Or is it just a number assigned? Then How do hits of various size affect the RB? I assume larger shells can reduce it faster than smaller shell size hits. And is it only hits below the WL or any hull hit? Might as well ask about torpedoes too… what RB affect/amount does a torpedo hit give and is it standard across the board or based on type of ship hit?
thanks….

Hi BuckeyeBob,
You wrote – "In the use of reserve buoyancy, More info please…. Do you figure RB for the ship and assign blocks of: X amt per block, to each ship? Or is it just a number assigned? Then How do hits of various size affect the RB? I assume larger shells can reduce it faster than smaller shell size hits. And is it only hits below the WL or any hull hit? Might as well ask about torpedoes too… what RB affect/amount does a torpedo hit give and is it standard across the board or based on type of ship hit?
thanks…."

Lots of questions. I will do my best . . . . .
Once the RB (Reserve Buoyancy) value is determined, I create a rectangular field of five rows of hit boxes, with each row being of an equal number of boxes. If the RB value of the ship is not evenly divisible by 5, any differential is accounted by the lower rows possessing fewer boxes. Example: if the RB value = 63, then rows 1, 2 and 3 would count 13 boxes each, while row 4 and 5 would count 12 boxes each.

Damage effected by projectile hits varies according to: projectile weight; projectile type (AP/CP/HE); armor penetration versus protection; and a randomizing factor. This will at first appear a bit odd compared to typical rules (the grouping of 14in, 15in and 16in in the same damage effect category, for example) but the modifiers act in favor the bigger calibers .

Shell Weight – - – - AP – - – - – CP – - – - – - HE – - – - – - Examples of guns
(in pounds)

</= 10 – - – - – - – - – - – - – - – - – - – - -- – - – - D-4 – - – - – 6-pounder TB gun)
</= 20 – - – - – - – - – - – - – - – - – - – - – - – - – D-3 – - – - – 12-pounder
</= 40 – - – - – - – - – - – - – - – - – D-3 – - – - – D-2 – - – - – 88mm, 4in, 4.1in
</= 75 – - – - – - – - – - – - – - – - – D-2 – - – - – D-1 – - – - – 4.7in, 5in
</= 150 – - – - – - – - D-2 – - – - – D-1 – - – - – D+0 – - – - 5.5in, 6in, 6.7in
</= 300 – - – - – - – - D-1 – - – - D+0 – - – - – D+1 – - – - – 8in
</= 600 – - – - – - – - D+0 – - – - D+1 – - – - – D+2 – - – - – 9.2in, 10in
</= 1200 – - – - – - – D+1 – - – - D+2 – - – - – D+3 – - – - – 11in, 12in
</= 2400 – - – - – - – D+2 – - – - D+3 – - – - – D+4 – - – - – 13.5in, 14in, 15in, old 16in
</= 4800 – - – - – - – D+3 – - – - D+4 – - – - – D+5 – - – - – 18in

D = the score one six-sided die; +/- modifiers adjust D6 score for projectile size and weight.

- – -

Vertical (belt) armor classes =
XX – - – - – no armor – - – TBs, DDs, Merchant ships.
CL – - – - – </= 3in – - – - – Light Cruisers
PC – - – - – </= 5in – - – - – Protected Cruisers
CA – - – - – </= 7in – - – - – Armored Cruisers; Invincibles & Indefatigables
B/BC – - – </= 9in – - – - – Predreadnoughts; Later British Battlecruisers
BB – - – - – </= 11in – - – - Early dreadnoughts
BA – - – - – </= 13in – - – - Super-dreadnoughts
AA – - – - – </= 15in – - – - Unusually heavy armoring (CT, turret face.
Example of determining damage effect -

A 13.5in CP projectile scores a hit upon a German BB, on the unprotected side of her bow above the forward belt or upon the unarmored forecastle deck.

Assume that the vertical AP capability of the projectile at the striking range = PC (5in)

13.5in CP = D+3 basic value.
Armor penetration (CP) = two levels above target ship protection at the point hit = +2.
Net damage effect = D+5 (Note – if striking superior armor, a penalty of -2 per difference in level is imosed).

Throw 1D6.
Add +3 and +2 to base D6 score
Possible results are
1 + 5 = 6
2 + 5 = 7
3 + 5 = 8
4 + 5 = 9
5 + 5 = 10
6 + 5 = 11

Square the result and divide by 10 to obtain points of damage
Note – I know this step seems superfluous, but it makes an important difference with smaller caliber shells.

6 x 6 = 36 / 10 = 3.6 = 4 points damage
7 x 7 = 49 / 10 = 4.9 = 5 points damage
8 x 8 – 64 / 10 = 6.4 = 6 points damage
9 x 9 = 81 / 10 = 8.1 = 8 points damage
10 x 10 = 100 / 10 = 10 points damage
11 x 11 = 121 / 10 = 12 points damage

The AVERAGE damage effect will be 7.5 points of damage.

Applying the damage to the RB boxes (read carefully) –
> Each point of damage caused by a projectile hit above the waterline is considered to ruin the watertight integrity of one RB box without necessarily flooding it. These reserve buoyancy hits (called RB hits) are marked off from left to right starting with the top row of boxes by putting a single diagonal slash through one box for each point of damage.
> Each point of damage caused by a projectile hit on the waterline or by an underwater weapon below the waterline is considered to have not only ruined the watertight integrity of one RB box, but also to have flooded it. These flooding hits (called FL hits) are marked off from right to left starting with the bottommost row of boxes by marking it out completely with an X in the box.
> When no open boxes remain , each point of damage from a new RB hit converts one box with existing RB damage into a flooded box and each point of damage from a new FL hit causes two boxes with existing RB damage to be concerted to FL damage.

As each row of boxes is filled with FL damage, the speed of the ship is reduced, with system damage to engines and/or boilers causing additional loss of speed over and above. When all the boxes are marked off as FL damage, the ship is considered DIW (as opposed to sunk) and will be abandoned by her crew.

Damage effects of underwater weapons are a different issue, which I will tackle in a follow-up post.

B

Reserve buoyancy points for any conventional ship =

[W/L] x [Beam] x [Amidships Freeboard]
16,000

Note – this formula has been simplified to a single denominator for ease of computation; the original formula includes corrections for: curved ship's planform curvature versus LxB rectangle; internal permeability; long ton volumetric measure; 50 percent critical limiting factor.

One buoyancy point = the volume occupied by 100 long tons of sea water. The computed number of buoyancy points actually = one-half the total theoretical volume. For game purposes, the one-half mark is deemed to represent the point where progressive flooding and reduced transverse stability of the damaged ship have reached a point of unacceptable risk.

B

Blutarski
thanks for the info. It seems our thinking along these lines is very similar. I had just read a PDF on the internet on how to figure RB and the diagrams it had covered many of the aspects you mentioned.
PDF link
So far I had come up with a partial formula based on my reading:
W/L x beam x amidships freeboard x .65 but felt it was missing something….I see if I divide this result by 10,000 I come up with a very similar number that your formula does.
Many rules use flotation points per ship, a flotation point being a box, but most times this is based on a displacement formula. I was also stuck with how to handle hits above the WL as I felt they could affect flotation but not to the extent as a hit below WL. I like your tracking RB methodology concerning the slash for above WL hits and x for below WL, and how they are marked off once all RB boxes have a mark in them.
What got me interested in this issue was my reading the Battlestations! rules by A. Zimm. There is something in those rules where a bouyancy formula is used to calculate capsizing…I recall that the player needed to figure 15% and 25% of something for the ship…have to reread that section….which got me thinking about bouyancy versus reserve bouyancy and metacentric height….

Thanks once again for your explanation.

Hi BuckeyeBob,
I too have a precious copy of "Battle Stations". It had a great influence upon me. Alan Zimm incorporated much good material from the WW2 era US Naval War College wargame rules ("professional quality") into "Battle Stations". As I recall, the paper "Battle Stations" was then morphed into the PC-based "Action Stations" – a highly regarded game in its day – which sadly was unable to keep pace with the new O/S's and graphics standards.

B

Blutarski,
Thank you for the explanation. I too have been looking for a similar solution. Originally my rules used displacement as the basis for survivability, but during the lifetime of a real ship modifications and additions usually increase the displacement and actually mean less reserve of buoyancy. For instance during WW2 the addition of radar and light AA raised the centre of gravity sometimes resulting in ballast being added to a ship or fuel levels not being permitted to fall below a certain level.
Now my rules are still based on displacement but take into account compartmentalisation freeboard etc. Sometimes it is a "finger in the air" job, but it seems to work.

I managed to track down my torpedo data. Is anyone still interested?

B

Blutarski
Of course I am interested. Thanks for going thru the trouble of finding it and sharing with us.

Damage effects of underwater weapons

Factors to be considered –
> Explosive power of the warhead.
> Size of the stricken ship.
> Compartmentation/watertightness of the stricken ship.
> Resistance of the torpedo defense system, if in fact present.
> Depth of the torpedo hit relative to the ship's waterline.
> State of ship's battle-readiness.
> Damage control and pumping capacity.

A dreadnought battleship with a displacement of 25,000 long tons occupies a volumetric space below the waterline of 25,000 x 40 = 1,000,000 ft3. A long ton of steel occupies only ~4.667 ft3 versus a long ton of water, which occupies 40 ft3. Allowing for a permeability factor (0.65?) to account for fuel, stores, ammunition, equipment, furniture etc, this implies a large unoccupied volume theoretically at risk of flooding.

This is important to appreciate. Any part of the underwater hull opened to the sea by a torpedo or mine hit will typically fill rapidly and, once the amount of flooding =/> reserve buoyancy, the ship will sink. In order to minimize the risk of sinking, the underwater volume of a ship is carefully sub-divided into a number of individually watertight zones by means of transverse watertight bulkheads. For example, 16 major watertight transverse bulkheads divided the hull of SMS Seydlitz into 17 individually watertight zones. Any of these zones might well be further subdivided by additional transverse and/or longitudinal bulkheads to create separate engine/condenser spaces or to make smaller boiler rooms and so on. Numerous partition bulkheads will also exist, but they are typically not watertight.

The above is all fairly obvious; I just wanted to lay out the "landscape", so to speak.

OK. What happens when a torpedo strikes a ship (and explodes)? Answer: it depends upon:
1 – The power of the warhead.
2 – Where the torpedo strikes the ship.

Power of the warhead (WW1 era)
This is most commonly expressed in pounds of TNT equivalent. WW1 torpedo warheads contained a variety of explosives – wet guncotton (WGC), TNT, Amatol, Hexanite to name a few. In order to establish warhead power, start with the warhead weight and adjust for explosive type.

Examples (Likelihood of rupturing a transverse watertight bulkhead at 10 from detonation point -
200lb WGC warhead = 0.50 @ 10ft; 0.00 @ 20ft
320lb TNT warhead = 1.00 @ 10ft; 0.40 @ 20ft
515lb TNT warhead = 1.00 @ 10ft; 0.60 @ 20ft
440lb Hexanite warhead = 1.00 @ 10ft; 0.60 @ 20ft
A ruptured transverse bulkhead means, of course, that two adjacent watertight zones may be compromised.

More Later …..

Here is how I have approached torpedo damage effects –

First you need a (simple) underwater plan of the target ship. I take the waterline length of the ship and divide into three equal segments: , forward, midships, and aft. The midships section is a long rectangle containing the boiler spaces, engine spaces and any midships or wing turret positions. The forward section is drawn as a long thin isosceles triangle representing the bow including forward turret(s), torpedo flat, etc. The after section is another isosceles triangle containing stern turret(s), steering machinery, torpedo flat, etc. Just the stuff important to the game.

In the midships section, draw in the major W/T bulkheads that define boiler rooms, engine and condenser rooms, magazines. If the ship has a torpedo defense system, represent it by a line parallel and close to the long sides of the rectangle amidships rectangle.

In the forward and after sections, draw in transverse bulkheads to distinguish turret/magazine positions, torpedo flats, steering spaces. Separation between transverse bulkheads in these areas should be no less than 30ft apart.

We have just created a basic underwater plan of the ship and now must fill in appropriate flooding values for each section/compartment. This map represents the hole in the ocean occupied by the underwater hull of the ship. The official displacement of the ship = the number of tons of sea water that would be required to fill said hole if the ship were not there.

Let's assume that the official displacement = 24,000 tons. Allowing for 0.67 permeability factor, we get a net floodable volume within the underwater hull of 24,000 x 0.67 = 16,000 tons, which equals 160 "hit boxes" worth 100 tons of flooding each. We now need to assign flooding values to all the little compartments drawn into the underwater map. Based upon the geometry of the map diagram, the midships section accounts for one-half (80 hit boxes) and the forward and after sections each account for one-quarter (40 hit boxes each).

For the midships section, assign an appropriate number hit boxes to each compartment based upon its share of the total area of the midships section.

For the forward and after sections, look at the keel line length of the triangle from tip to base. If the length of the triangle has been divided evenly, use the following rule of thumb, depending upon the number of divisions –

Divisions – - – - – Relative shares of hit boxes per division
2 – - – - – - – - – - – 1 / 3
3 – - – - – - – - – - – 1 / 3 / 5
4 – - – - – - – - – - – 1 / 3 /5 /7
5 – - – - – - – - – - – 1 /3 /5 /7 /9
6 – - – - – - – - – - – 1 /3 /5 /7 /9 /11

Example –
The forward section of the ship is divided into five units of equal length on the keel line. The units, starting from the tip of the bow have relative share of the forward section flooding volume = 1, 3, 5, 7 and 9, making a total of 25. The total underwater volume of the forward section = 160 x 0.25 = 40 hit boxes. These 40 boxes are apportioned to the five subdivisions in the forward section as follows
1/25 = 0.04 x 40 = 1.6
3/25 = 0.12 x 40 = 4.8
5/25 = 0.20 x 40 = 8.0
7/25 = 0.28 x 40 = 11.2
9/25 = 0.36 x 40 = 14.4

Which rounds off to 2 + 5 + 8 + 11 + 14 = 40 hit boxes for the forward section.

Since a modern torpedo has a high likelihood of disrupting a nearby transverse bulkhead, the likely outcomes of a torpedo hit in the forward section could yield the following sorts of results –

Counting from the bow –
Subdivisions 1 and 2 flooded = 700 tons flooding
Subdivisions 2 and 3 flooded = 1300 tons flooding
Subdivisions 3 and 4 flooded = 1900 tons flooding
Subdivisions 4 and 5 flooded = 2500 tons flooding (unless there are longitudinal torpedo bulkhead protecting the magazines.

- which, in terms of flooding values, are within the realm of historical reason. You can get the basic flooding and system damage effects with a single look at the underwater hull diagram – no charts or calculators required.

In the next installment, the issues of length of shell plating destruction, risk to transverse bulkheads, value of torpedo protection systems versus torpedo warhead size will be discussed.

I'm hoping that you are finding this useful. Do let me know if this is not up your alley. It has been a bit of work to re-assemble all this stuff from dusty files and type it up.

B

Blutarski
Very interesting. Did Battlestations! influence how you came up with this? It has a similar division of spaces methodology.
If I understand what you are doing here…You determine one of 3 areas a torp hits; bow, midsection, stern. Subdivide each into a number of boxes. Then based on its explosive power mark off a number of the boxes in that Section.

It is a bit of work when typing up old notes etc. But I find it fun to review work I started on 30-40 yrs ago on various games or rulesets and think about how they evolved over time and how I play them now.

thanks for the information….
Glen aka buckeyebob

I certainly appreciate seeing it. Thanks.

I'm taking somewhat of the same approach in dividing a ship into historic sections/transverse bulkheads. I had a problem determining the damage and flooding so this discussioon helps.

I'm using this link to help quantify torpedo and underwater damage: link

If you can determine the with of the blast and where it hit you can determine how many compartments and transverse bulkheads will be affected. Then it determining the floooding, component and system damage and shock damage.

Wolfhag

Thank you, gents. Onward and upward, then.

Hi BuckeyeBob –
1 – Yes. Alan Zimm's "Battlestattions" rules first put me onto this approach. Looking back on "the journey", I don't think there is any other way to properly quantify/model torpedo flooding effects.
2 – Re hit location, it is not exactly the way you surmised it. I use 2D10 to generate a 1-100 value, with each unit = 10ft. However I only notate/quantify the locations of the transverse bulkheads. If the 2D100 location of a torpedo hit falls on (or near enough depending upon torpedo warhead size) the transverse bulkhead is deemed to have failed and the adjacent compartment will also flood.

Hi Wolfhag -
Stay tuned for the next installment. It will discuss structural damage effects versus warhead weight, based on some work done back in the day by DK Brown. It will cover three issues –
> shell plating destruction/compromise
> risk to transverse bulkheads
> torpedo defense systems (a sticky topic).

B

Next installment – Physical torpedo damage effects.
This is based largely upon material presented by DK Brown and collected by me over the years.

Introductory remark –
As I am trying to keep this simple, the discussion below assumes the same standard of WW2-era warship construction quality, design efficiency and quality of materials. Adjust as you see fit for various eras and ship ages.

- – -

Warhead weight = equivalent value in terms of pounds of TNT, where –
One pound of Wet Gun Cotton (WGC) = 0.5 pounds of TNT.
One pound of Hexanite = 1.6 pounds of TNT.

Other types of high explosive (Amatol, Torpex for example) were employed over the years in torpedo warheads. TNT equivalency for these can be found via a little research.

Width of shell plating damage in feet = 5 x [Warhead Weight]^1/3

Likelihood of rupturing a transverse bulkhead –
Warhead weight in equivalent pounds of TNT divided by the square of the number of feet from point of torpedo impact x 0.50 = the percentile likelihood of rupturing a transverse W/T bulkhead.

- – -

Examples –

400-lb TNT warhead:
Overall width of damaged shell plating – 37 ft (i.e. within +/- 18.5 ft of impact point)
Hit proximity from point of impact to give 100pct chance of transverse bulkhead failure – 14 ft
Hit proximity from point of impact to give 50pct chance of transverse bulkhead failure – 20 ft

800-lb TNT warhead:
Overall width of damaged shell plating – 46 ft (i.e. within +/- 23 ft of impact point)
Hit proximity from point of impact to give 100pct chance of transverse bulkhead failure – 20 ft
Hit proximity from point of impact to give 50pct chance of transverse bulkhead failure – 28 ft

1350-lb TNT warhead:
Overall width of damaged shell plating – 55 ft (i.e. within +/- 27.5 ft of impact point)
Hit proximity from point of impact to give 100pct chance of transverse bulkhead failure – 26 ft
Hit proximity from point of impact to give 50pct chance of transverse bulkhead failure – 37 ft

Although any distances and/or percentages of likelihood can be computed, I have tended to round off plate damage dimensions and torpedo impact distances to the nearest 10ft increment for the sake of simplicity. Likewise, I compute transverse bulkhead failure risks for 100pct and 50 pct only. IMO, complexity and detail beyond those thresholds do not justify themselves. YMMV; if so, go for it.

- – -

Applying to actual game play –

Each ship needs a simple underwater ship chart showing the various important watertight compartments and their assigned flooding volume (as discussed in a previous post). I use 10ft dimensional increments, which permits a torpedo impact point to be randomly located along the waterline length of any warship by the throw of two differentiated D10s to generate a 1-100 number (i.e. 100 = 1,000 ft). Only the transverse bulkhead positions need to be numbered for location.

The BIGGEST problem is accounting for the influence of Torpedo Defense System (TDS) that might be present. Generally speaking – TDS in WW1 are typically only found with newer dreadnoughts (and rarely with certain monitors); in WW2 they will be found in all modern capital ships, rebuilt dreadnoughts and many aircraft carriers.

Torpedo Defense Systems are customarily "rated" according to the size of attacking torpedo warhead they are believed to be capable of withstanding. These ratings are normally based upon physical tests of the TDS design versus real explosives. But problems may arise when tests are not carried out properly; other difficulties may arise when the nature of the test is artificial to the degree that it requires extrapolation to estimate the rating of a TDS as ultimately built. The reliability of these values therefore may not = holy scripture. The age of the ship (old ships = tired ships = leaky ships) can be a factor. An interesting example of this last case is the experience of USS NEVADA at Pearl Harbor. She was a WW1 era super-dreadnought re-built in the mid-1920s to incorporate (among other things) a new 22ft deep early design liquid-loaded TDS rated to resist a 400lb TNT warhead. A single 18in aerial torpedo with a warhead estimated at 400lbs TNT equivalent breached her TDS by splitting/tearing the seams of the innermost holding bulkhead; along with some minor bomb damage forward, the watertight integrity of the ship was found to be in terrible condition and the ship sank in the channel as a result of uncontrollable progressive flooding. Those TDS rating are not reliable predictors in every case.

Some other issues with TDS: they typically only cover the vitals of the ship, and they may be reduced to slightly less resistant system depths at the extremities.

I'm still pondering how to tackle this TDS issue in a reasonable way. Meanwhile, back to our scheduled programming –

Assume a 400 lb TNT torpedo
Shell plating damage w/in +/- 20ft of impact point.
100pct chance of transverse bulkhead destruction w/in 10ft.
50pct chance of transverse bulkhead destruction w/in 20ft.

This torpedo hits at position 24 (240ft from the bow). There is a transverse bulkhead at position 26.

1 – If shell plating damage exceeds distance to the bulkhead, the torpedo defense system (TDS) of the adjacent compartment (if present) will flood; if no TDS present, the adjacent compartment will flood. The shell plating damage does not exceed the distance to the transverse bulkhead.

2 – There is a 50pct chance of destroying the transverse W/T bulk at 20ft from impact point. A 50/50 throw of the dice destroys the bulkhead and the adjacent compartment is marked off as flooded.

3 – Add up all those flooding value of the affected compartments and mark off as flooding hits on the previously described reserve buoyance chart.

4 – Mark off any systems engine rooms, boiler rooms, magazines, etc lost due to flooding and reduce speed and armament accordingly.

- – -

Next post will be a short discussion re ship stability in a damaged condition and the effects of lists upon shipboard operation.

B