Logi's Springsharp

[Nobody]

I remembered some more stuff, it is from Stefan Zima's "Ungewöhnliche Motoren" (in English: Unusual Engines)

The 12000 HP Engine (1917, SMS Prinzregent Luitpold)
A 6 cylinder double-acting two-stroke in-line engine. Aside from some nice, but not very useful details (nothing about weight and size - apart from a picture I'm almost certainly not allowed to post) the interesting part is this (loosely translated by me):
"At 12160 PS a fuel consumption of 214 g/PSh Carbolineum and 29 g/PSh ignition oil was measured." So that's a total of 243 g/PSh for near maximum output.

MAN MZ 42/58 family (Deutschland-Class)
Fuel consumption: 163 g/PSh, but requires auxiliary engine (see previous post)

MAN MZ 65/95 (1938, H-class)
http://www.deutsches-museum.de/en/collections/machines/power-engines/combustion-engines/diesel-engines/large-diesel-engines/marine-diesel-engine-1938/

MAN ZV24 32/44 (1942, "Spähkreuzer" Z51)
Sometimes also named "V12Z32/44". A 24 cylinder double-acting two-stroke V-engine.

		specific weight
continues power	10000
max power	12500 to 12600	5.2 kg/PS
with ATL ("Turbo")	15000	4 kg/PS

The sole survivor is on display in Sinsheim

Other places were stuff like this was discussed before:
http://warships1discussionboards.yuku.com/topic/20470/German-Capital-Diesel-Engines
http://www.forum-marinearchiv.de/smf/index.php/topic,9602.320.html
http://www.kbismarck.org/forum/viewtopic.php?f=37&t=775&start=15

[Logi]

A small clarification desired;

	Deutschland/Lützow	Admiral Scheer	Admiral Graf Spee
Machinery output at 250 rpm	48.390 shp	52.050 shp	54.000 (Pse)

M9Z42/58 details		Deutschland/Lützow	Admiral Scheer	Admiral Graf Spee
peak power	7100 PSe
continuous power	6655 PSe
fuel consumption	~200 g/PSh
engine weight [t]		900	982	1013
specific weight (design/actual) [kg/PSe]	11,5	12,4	13,53	13,96
machinery weight				1716 t

I assume the second table details the per engine weight and power output and the first table details the total power output on the ship?

[Logi]

I've been working on a suggested formula published in a research paper. Unfortunately, the paper is modern, so most definitely the machinery weights are also modern estimates. I've been able to derive a formula using the suggested one to be accurate to ±10% during the period of interest. In general, I would not do this, preferring to rely on the standard methods of naval architecture, but the alternative is neither simple nor pretty. I also have to mod my existing modifier value for Geared/Direct/Turbo-electric drives.

[Nobody]

A small clarification desired;

	Deutschland/Lützow	Admiral Scheer	Admiral Graf Spee
Machinery output at 250 rpm	48.390 shp	52.050 shp	54.000 (Pse)

M9Z42/58 details		Deutschland/Lützow	Admiral Scheer	Admiral Graf Spee
peak power	7100 PSe
continuous power	6655 PSe
fuel consumption	~200 g/PSh
engine weight [t]		900	982	1013
specific weight (design/actual) [kg/PSe]	11,5	12,4	13,53	13,96
machinery weight				1716 t

I assume the second table details the per engine weight and power output and the first table details the total power output on the ship?

Yea more or less. First table is per ship the second was supposed to be per engine. However, machinery and engine weight is also per ship, while the specific weight is basically "engine block" only.

On a side note: in the late 50s the specific weight of a civilian/merchant diesel engine was ten times higher (at 40 to 50 kg/PS) than that of the ZV 32/44 almost 20 years before!
Smaller engines have a better specific weight. For example aircraft and airship diesel weighted about 2 kg/PS. The submarine engines on the other hand are no better the ones used on Admiral Graf Speed or the H-class, achieving 14.4 kg/PS in their latest incarnations (the highly charged M6V 40/46 used in the type XXI for example).

MAN W10V 26/33 (1926, K-class light cruisers)
A normal 4-stroke engine. About 730 kW, but only 900 WPS - so almost 10% loss trough the (hydraulic) gearing to the screw. Design target: 5 kg/PS.

[Logi]

Thanks to the data provided by Nobody, I've managed to resolve the Engine/Bunker issue.

The only details left to do are in order of difficulty:

• Weapons and Ammo Weight
• Subtract Deck Weight for Barbette Holes
• Deck & Hull Space Calculation
• Crew Size Estimation

Hopefully (fingers-crossed), I'll have enough time next weekend to finish all the math and move onto developing a usable GUI.

As a preview of added features to look forward to:

• Simple Superstructure Simulation
• Ship Parallel/Smooth Midbody Choice
• Ship Aftbody Shape Choice
• Tapering and Sloped Belt Armor
• Adjustable Depths (Below Waterline) Belts
• Individual Deck Thickness and Height
• Ship Speed in Trial and Actual Service by Region
• Weight and Fuel Variation by Direct/Geared/Turbo-Electric and Diesel/Reciprocating/Steam

Perhaps you would be happy to hear, Nobody, that all the entire file is in metric.

Edit: Belt Slopes completed
Edit2: Bulkhead (TDS) completed
Edit3: Conning Tower Armor Weight completed

[Logi]

I've converted the majority of the formulas and details into a simple command line C++ file.
Currently it does not include the option to add guns/armor and does not calculate hull strength, I'll have to spend some time (not this weekend most likely!) to wrangle it into user-friendly I/O.

If you want to test on the current file for kicks, download it here

It'll output the detailed report to the console and write it to "Report.txt" in the same directory. The "Report.txt" is formatted into a nice table that this forum accepts, so it'll look neat and tidy like the sample below!

Also, here is a current sample Report:

Length:	160.00 m
Beam:	16.00 m
Draft:	7.50 m
Freeboard:	6.00 m
Depth:	13.50 m
Block Coefficient:	0.527
Midship Coefficient:	0.951
Prismatic Coefficient:	0.554
Waterplane Coefficient:	0.675
Displacement:	10119 t
Wetted Surface Area:	3440 sq. m
Waterplane Area:	1727 sq. m
Max Speed:	34.0 kn
Cruise Speed:	18.0 kn / 10000.0 nm
Power Delivered:	110738 hp
Power Effective:	107141 hp
Froude Number:	0.442
Bunker Size:	2966 t
Service Allowance:	25%
Hull Weight:	2277 t
Wood & Outfit Weight:	557 t
Machinery Weight:	3071 t
Equipment Weight:	464 t
Superstructure Weight:	279 t
Admiralty Coefficient:	21.77
Engine:	Geared Steam Turbine
Length of Superstructure:	35.00 m
Aftbody Shape:	V
Longitudinal Center of Buoyancy:	-8.38%
Longitudinal Center of Gravity:	2.80%
Vertical Center of Gravity:	6.99 m
Metacentric Height:	1.07 m
Roll Period:	6.65 s
Tonnes per centimetre immersion:	17.70
Moment to change trim one centimetre:	143.14
Bow Entrance Angle:	5.25 deg
Total Efficiency:	0.97%
Length of Engine Room:	70.04 m

[Logi]

A small update:

After a while of on and off work on this I've managed to get high-speed vessels like the IJN Shimakaze working in this. Some stats:

User Inputs

Length:	126m
Beam:	11.2m
Draft:	4.15m
Avg Freeboard:	4m
Std Displacement:	2,610t
Power Delivered:	75,000 shp
Design Speed:	39kn
Shafting Type:	Geared
No. of Shafts:	2
Aft Body Shape:	V
Transom Stern?	Semi
Design Year:	1941
Engine Type:	Steam Turbine
Cruise Speed:	18kn
Range:	6000nm
Percentage Coal:	0%

Which spits out a corrected speed of 40.19kn. If I switch the engine power to 79,200 shp, which is the power at which Shimakaze achieved it's 40.9 trial speed, the corrected speed becomes 40.92kn.

I've tested the new calculation method for USN and IJN ships from ~1910 to 1950 and the results are very close - varying at most by less than 1 kn. I haven't tested it for older or newer ships though.

It's reliant on three correction factors: Power Density, Size, and Year
These are 0.913, 0.784, and 1.041- respectively for Shimakaze (it's not a linear equation though).


The only thing missing on propulsion is stuff like Nuclear, Gas, and Diesel powerplants - I had partially solved it at one point, but I seem to have lost my notes in the intermission.


The question I have though is whether the value of 2,352.63t for displacement consumed by the ship without weapons/armor is reasonable. Given what SS seems to think Shimakaze's armament weighed, it seems to be about 80t too light.