Hit Locations

[miketr]

I am going to be working on a program to take a SS report and generate a location chart for determine hits.

In basic the program will take the length, freeboard of the hull and generate an area.  Then it will determine home much of said area is covered by upper belt, end belt, main belt, un armored, primary guns, secondary guns, etc.  End result will be a percentile table with location noted and armor at that location.

EX (don't pay attention to the numbers here this is just an example to show people what I am talking about in general terms)

1-20, Main Belt, 9.84" / 250mm
21-30, Upper Belt, 0" / 0mm (un armored)
31-40, End Belt, 5" / 127mm
etc...

This table is checked only after any to hit table is used.

A couple of thoughts I have.

1) How do we want to handle below the waterline hits in terms of the total "hitable" area?

2) Chance of a deck hit / other turret location hits. For the former I would like to break things down into a short, medium and long range table but what percent of hits should be within those three brackets and what do we want to call short, medium and long range?

3) How do we want to handle turret and other above deck weapons hits in terms of chances relative to the hull. 

4) Related to #3 hull mounted secondaries.

[P3D]

Whether a shell hits horizontal or vertical armor, it depends on angle of fall - should be in the relevant gun tables.

My 'algorithm' to determine hit location table was the following - for hits against vertical armor.

1. Assume a valid target area = Length x Height.
Height is freeboard height + 1-2 deck height for superstructure + some nominal height (say 1m) below the waterline.

Hit zones - mainly area ratio
A. waterline&below. Say +-1m from battleline with relevant end/main belt length. This would allow water into the ship thus reducing flotation.
A1. Machinery - assume say 67% of MB is machinery unless you are willing to do more calculations
A2. Magazines
A3. Plunging shells. In case of a waterline hit, there's a chance the shell goes under armor. Depending angle of fall, coverage, ship facing etc.
B. Main belt Above Waterline
C. Ends AWL - armored or not
D. Upper belt

Above calculations all area-based. About hits on all other stuff, they are usually fall into the 1-2% range. I will send you  the examples I had.
So give 1-2% chance for the following special hit locations:
- each main gun turrets (might be more, would need some calculations)
- each main gun turret barbette (might be more, would need some calculations)
- each secondary mount/hoist, or groups of such
- CT
- radio room
- Bridge
- Foremast (say main FC/spotting)
- Mainmast (say secondary FC/spotting)
- Funnel uptakes within hull (might be more, would need some calculations)
- boats

Rest goes into general unarmored hull/superstructure.

[miketr]

Yours is a little more detailed but we are on the same page in general.

So you want H vs. V hit figured by the gun table?  Thats fine with me.  For the horizontal table things to hit would the following.

1) Deck Armor
2) Turret tops
3) Other gun tops

I will PM you my email address to send me what you have.  Its been a while since I coded anything so it will take me a week to three to come up with something.

Michael

[miketr]

OK Its been a while but I want to attempt to get back into this.  I think for now I am going to make an excel sheet to do this and then maybe, perhaps, dig out the code books.

For right now I am going to say we keep this simple.  Two custom to hit locations, one horizontal and vertical.

Now for the vertical table.

We have the area that can be hit broken into 3 sections.

1) Hull area below water level (draught x length)
2) Hull area above water level (average freeboard x length)
3) Deck structures such as turrets, conning tower, funnels, secondaries, etc. 

Now I have two problems I need to figure out.

First is that most of the time when a shell hits the water it deflects and looses energy so in effect the under water area of a ship is actually smaller.  The question is how much smaller?  Should we halve the under water area?  Reduce it by X% but what is X?

Second is how much area do the various other structures take up?  We have turrets, barbettes, secondary, tertiary, etc gun mounts, funnels, range finders, bridge, conning tower, supper structure, etc., etc.

Any suggestions for these two issues?

So we will get something like this.

Class Name:	Nation Name:	Ship Type:
Percentile	Location	Armor
1-5	Aft Ends Belt	4"
6-10	Fore Ends Belt	4"
11-20	Upper Belt	6"
21-26	Main Belt, Machinery	12"
27-40	Main Belt, Magazines	12"
41-42	Main Turret, Face; #1	12"
43-44	Main Turret, Barbette; #1	10"
45-46	Main Turret, Face; #2	12"
47-48	Main Turret, Barbette; #2	10"
49	Secondary / Casement; #1	6"
50	Secondary / Casement; #2	6"
51	Secondary / Casement; #3	6"
52	Secondary / Casement; #4	6"
53	Secondary / Casement; #5	6"
54	Secondary / Casement; #6	6"
55-57	Tertiary or other gun mounts	2"
58-73	General Hull	0
74-78	General Superstructure	0
79	Mast	0
80	Conning Tower	12"
81	Bridge	0
82-87	Funnel	0
88-89	Below Waterline, Aft Ends Belt	4"
90-91	Below Waterline, Fore Ends Belt	4"
92-94	Below Waterline, Main Belt, Machinery	12"
95-100	Below Waterline, Main Belt, Magazines	12"

[Kaiser Kirk]

First is that most of the time when a shell hits the water it deflects and looses energy so in effect the under water area of a ship is actually smaller.  The question is how much smaller?  Should we halve the under water area?  Reduce it by X% but what is X?

It's significantly.  I don't know if I can dig up the information or not, but once a shell hits the water it only will travel a very short way before becoming destabilized and tumbling to continue base first, likewise it will only dive so deep before turning up. This creates a very small, albeit critical, danger space.  As I recall, both are factors of the shell, not the target.

I've got a couple ideas where I may have run across the info, I'll try to browse them in the next couple of days. 

As for locations, with varying heights of belts and freeboards, the belt/non belt areas are not going to be consistant proportions. 

[maddox]

As I can recall, it's a question of meters before a heavy shell just sinks. 

Or if the fuse is triggered, explodes only a few meters under water. With the small bursting charge of an anti armor shell, that ain't a too big issue.

For smaller unarmored or very light armored ships, it's more than annoying. Heavies are another matter of course.

[miketr]

As for locations, with varying heights of belts and freeboards, the belt/non belt areas are not going to be consistant proportions. 

The user would enter the size of the various belts, the size of the hull itself and that will give us two area's and then the spreadsheet would create the custom table to assign the various hit values.

On the below water area, any help would be great.  Perhaps I should grab a copy of Jutland: An Analysis of the Fighting by John Campbell and look up the historic results there.

Michael

[miketr]

As I can recall, it's a question of meters before a heavy shell just sinks. 

Or if the fuse is triggered, explodes only a few meters under water. With the small bursting charge of an anti armor shell, that ain't a too big issue.

For smaller unarmored or very light armored ships, it's more than annoying. Heavies are another matter of course.

Any suggestions for the math sir?

Michael

[maddox]

I have only 1 direct reference, water is 830 times as dense as air at sealevel.

Taking in acount the quadrating effect of distance, I can see a shell losing speed very very fast.

[miketr]

Some other person has borrowed Jutland: An Analysis of the Fighting by John Campbell from the library.  I got no real direction from the Warships1 board other than its possible and could be devestating but very unlikely.  As such I am going to suggest that we reduce reduce the effective size of the underwater area of a hull to 20%.  I may update this whenever I get access the Campbell's book but that might be a few weeks.

OK I have another issue, the ships superstructure.  It occurs to me that as we go forward in time tht superstructures became larger and there for became larger targets.  Any suggestions as to how much of a target they reprsent over time?

I will try to have something in a few days for people to look over.

[miketr]

For Magazine and Machinery area of the hull I need some suggestions for those in the know.

I would assume machinery space would be from about 2/3 of the height of the main belt above the water line and all the way down.  Spring Sharp provides us some info for length with the minimum needed to cover machinery and magazines.  So as a generic value home much of that length goes to Mags and how much to machinery?

[Guinness]

Simple answer is: it depends :)

Helpful, I know. Magazine size is dictated by two values: the weight of the ammunition and the number of main battery shells. Let me crack open SS in my little .net decompiler thing and I can try to tell you the actual formula.

Similarly, machinery length (well really machinery volume, I suspect) is going to be dictated by S/IHP and engine year, I believe.

More in a little while hopefully.

[Guinness]

Deconstructed .net makes me want to cry, but...

SS calculates whether you have enough armor to cover magazine and machinery spaces thusly:

first it calculates magazine size by multiplying the first battery's number of shells by the shell weight by number of barrels. That's pretty straightforward.

Then it divides 1 by the caliber of each of batteries 2-5 and adds 1 to that, multiplies that by the number of shells in the first battery's magazine, and multiplies that by the number of barrels, and multiplies that by the weight of the shells for that battery.

Then it adds up all those weights to get the total magazine weight, divides that by 2240 to get the weight in long tons instead of pounds, and multiplies that by 1.244444. That gives us the final magazine weight in tons.

Then it calculates armor belt coverage by simply dividing main armored belt length by waterline length by 0.65.

Then it calculates how much room there is in the hull. For this I'll just copy and paste the pertinent code:

    this.roomHullFloat = (((((this.magazine + (this.displacement * 0.02f)) + (this.gunsUnfixedWeightAll * 6.4f)) + (this.engineWeight * 3f)) + this.miscWeight) / (this.displacement * 0.94f)) / (1f - this.torpHullSpace);
    if (this.armWeightTorpBulk > 0.1)
    {
        this.roomHull = (this.roomHullFloat * this.beam) / (this.beam - 20f);
    }
    else
    {
        this.roomHull = this.roomHullFloat;
    }

I think the reader can guess what all the variables there are. Displacement in SS is usually "normal" unless otherwise specified. torpHullSpace is the product of another calculation to discern how big the underwater torpedo rooms, etc. are, which is similar to the magazine calculation.

The actual comparison is just checking to see if the value for the Armor Belt coverage is greater than the value for hull room.

So in reality it makes no assumptions or evaluations here based on how tall the belt is, only how long it is, and then only as a function of weights, etc. Hope that helps.

[P3D]

Between the wars, the U.S. Naval War College developed a number of correction factors to allow for the effects of variation in conditions.  For example, starting at 100% -- i.e. baseline  conditions -- they would reduce hits by 20% if the ship were under concentrated fire, another 10% if the ship had turned more than 30 degrees in the last 3 minutes, another 20% for a large ship in rough seas (as opposed to 40% for a small ship in rough seas), and another 30% if the ship were firing nearly into a low sun, or if the ship were in the funnel smoke of the vessel immediately ahead.