WesWorld

There was a desire to look at the current Design Rules for Gentlemen expressed in another thread (German ZL-100). I'm starting a thread here for discussion on this topic.

My personal thought is that it might be worth reexamining where the break-point is between a required hull strength of 0.50 and 0.75. Currently, the breakpoint is 4,000 tons, it might make more sense to set this breakpoint at 3,000 tons, for cruisers above and destroyers below.

0.5-0.75 HS 0-3000tons

0.75 HS up to 6000tons if speed is >34knts

I'll try and sim Arethusa to see if this is sensible. I believe it should work for the moment until the engine weight problem with SS is sorted out.

For Capitani Romani, the HS is ~1.00 with the actual weight of her engines compared to the 0.47 that SS gives. So once we have improvements to SS, we change the rules once again to reflect this sort of thing.

One thing that would be good is to make clear whether the tonnage sizes specified in the Design Rules are light displacement, standard displacement, or what.

If not otherwise stated (like for material costs) we´re talking standard displacement.

Works for me, we should just be clear what it is.

I'd like to see the tonnages and hull strength correlations be somewhat less generous. Would this give us more realistic designs:

Under 24 knots: HS must be 1.00 or above.

Over 24 knots: [list]
1 to 2000 t: HS = 0.5
2001 to 4000 t: HS = 0.75
4001 to 6000 t: HS = 0.90[/list]

Quoted

2001 to 4000 t: HS = 0.75

This would make larger destroyers, like the Fletcher's, Mogador's, Z-23's, etc pretty difficult to design, I'd think.

Doc, looks good.

How do we deal with vessels already build to the actual rules?

If built or underway as of Q2/29, they're "grand-fathered" and considered legal.

Quoted

Originally posted by Hrolf Hakonson

Quoted

2001 to 4000 t: HS = 0.75

This would make larger destroyers, like the Fletcher's, Mogador's, Z-23's, etc pretty difficult to design, I'd think.

How about

Quoted

2001 to 4000 t: HS=0.65

?

Have to try it and see, I suppose. It may not matter much, though, since the problem-children are all products of the late 30s by which time we should (knock on wood) have SS 3.0 or later to use.

Nobody else who thinks he should add his opinion?

20001ton-4000tons with 0.75 or 0.65 HS is impossible.

How do you get Mogador or Le Fantasque?

I'm inclined to agree, though simming those ships with SS 2.1 may not be necessary if SS3.0 is out by then. How did your test of Arethusa come out? Tromp would be another ideal testbed for such a test.

1.00 is a good point for ships of 5000-6000tons. Arethusa comes out at about that level. Definitely not 0,75 HS.

Hmmmm. Maybe:
0-3,000 tons at 0.5
3,0001-4,500 tons at 0.75
4,501-6,000 at 0.9?

I'm doubting Tromp could be built at 1.0, and if Arethusa was over-built or stronger than she actually needed to be that would be no great surprise. The above would allow for Mogador and other large destroyers, give an ability to build Tromp if desired, but not overly benefit ships in the 5-6000 ton range vs ships in the 6,000+ ton range.

Alternatively:
0-3,000 tons at 0.5
3,0001-4,500 tons at 0.75
4,501+ at 1.0

This would assume that Arethusa is not over-built. It might be problematic for some smaller cruisers that have already been built, though I haven't looked to see if there would be a problem here or not.

Has anybody simmed these odd-balls (Tromp, Arethusa, Mogador, etc)? Seeing what their sims give would help me make a more informed decision.

Here's a version of Mogador, based on the info on http://navalhistory.flixco.info. The dimensions, armament (ammunition should be around 190 rds per gun, though), range, and standard displacement are all correct (freeboard I'm strictly guessing at, no data), but the speed is low by 2.3 knots and the engine output is low by about 25,000 shp. But at a cross-sectional strength of 0.50, this is about as close as I can get it.

Mogador, French Contre-torpilleur laid down 1934

Displacement:
2,760 t light; 2,885 t standard; 3,249 t normal; 3,541 t full load

Dimensions: Length overall / water x beam x draught
450.76 ft / 442.91 ft x 41.57 ft x 14.99 ft (normal load)
137.39 m / 135.00 m x 12.67 m x 4.57 m

Armament:
8 - 5.46" / 139 mm guns (4x2 guns), 89.50lbs / 40.60kg shells, 1934 Model
Breech loading guns in deck mounts with hoists
on centreline ends, evenly spread, 2 raised mounts - superfiring
4 - 1.46" / 37.0 mm guns (2x2 guns), 1.55lbs / 0.70kg shells, 1934 Model
Anti-aircraft guns in deck mounts
on centreline ends, evenly spread
4 - 0.52" / 13.2 mm guns (2x2 guns), 0.07lbs / 0.03kg shells, 1934 Model
Machine guns in deck mounts
on side, all forward
Weight of broadside 722 lbs / 328 kg
Shells per gun, main battery: 150
10 - 21.7" / 550 mm above water torpedoes

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 67,367 shp / 50,256 Kw = 36.70 kts
Range 4,000nm at 18.00 kts
Bunker at max displacement = 656 tons

Complement:
214 - 279

Cost:
£1.996 million / $7.983 million

Distribution of weights at normal displacement:
Armament: 82 tons, 2.5 %
Machinery: 1,722 tons, 53.0 %
Hull, fittings & equipment: 931 tons, 28.6 %
Fuel, ammunition & stores: 490 tons, 15.1 %
Miscellaneous weights: 25 tons, 0.8 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
778 lbs / 353 Kg = 9.6 x 5.5 " / 139 mm shells or 0.4 torpedoes
Stability (Unstable if below 1.00): 1.50
Metacentric height 2.7 ft / 0.8 m
Roll period: 10.7 seconds
Steadiness - As gun platform (Average = 50 %): 43 %
- Recoil effect (Restricted arc if above 1.00): 0.48
Seaboat quality (Average = 1.00): 0.75

Hull form characteristics:
Hull has rise forward of midbreak
and transom stern
Block coefficient: 0.412
Length to Beam Ratio: 10.66 : 1
'Natural speed' for length: 24.17 kts
Power going to wave formation at top speed: 66 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 15.00 degrees
Stern overhang: 1.64 ft / 0.50 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 23.16 ft / 7.06 m
- Forecastle (20 %): 16.40 ft / 5.00 m
- Mid (50 %): 16.40 ft / 5.00 m (14.73 ft / 4.49 m aft of break)
- Quarterdeck (15 %): 14.73 ft / 4.49 m
- Stern: 14.73 ft / 4.49 m
- Average freeboard: 16.11 ft / 4.91 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 191.2 %
- Above water (accommodation/working, high = better): 98.5 %
Waterplane Area: 11,850 Square feet or 1,101 Square metres
Displacement factor (Displacement / loading): 71 %
Structure weight / hull surface area: 44 lbs/sq ft or 215 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 1.26
- Overall: 0.55
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate
Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

25 tons reserved for 40 mines.



If you go to a required composite strength of 0.75, you have to slow to 34.3 knots and a engine output of 51,133, vs the real ship at 92,000+.

Could we be getting the horsepower wrong due to our own misunderstanding? SS reads out shp or Shaft Horsepower, which might not be the same as plain Horsepower output of an engine, as some horsepower is lost in transfering it to the shafts.

Right?

I don't think that's the problem, since the speed is also showing a serious difference. When I had the speed set to the actual speed of 39 knots, SS was showing a shp of 88,000 or so, so it might have been taking into account transmission losses (though I doubt it).