I hope we're not in danger of overcomplicating simming these ships though with considerations about ballast and wet and dry sims etc.
Well, the one thing you have to remember is that the actual speed and range are higher than you sim. That is also a 'problem' I encountered with submarines in SS where I originally thought "It
must have that speed" only to realize years later "Hey! We sim the sub 'in awash condition, just about to go under' meaning in reality the submarine will be higher in the water with the ballast tanks empty thus speed and range are a bit higher than is simmed".
When something like an LSD is underway, the well deck is empty and so are the ballast tanks, so for the actual speed and range you need to resim the ship but then lying higher in the water to get the correct speed for the given amount of power and the correct range for the given amount of bunkerage.
I've always assumed the boats on the boat were paid for as misc weight allowances for such craft in the report. I think there was an agreement to that effect somewhere at some time.
Yes. While I could not find the original mentioning of that agreement, I did see Hooman mention it in a thread discussing the LST rule. To me it only makes sense.
Below a test of the USS Ashland. There are two sims: one empty and one that takes the water in the well deck and in the ballast tanks into account. I actually went from the empty one to the loaded one which was kinda of a mistake as I just kept making changes over and over and over and over again altering the draught and freeboard values. The best way is probably to do it the other way around. The empty sim is purely there to calculate the amount of power needed for 17 knots and the amount of bunkerage for 8000nm at 15 knots. Ideally I would think that the empty displacements for both sims should be the same but I got tired of working on it so it is not perfect...
USS Ashland (empty), USN LSD laid down 1942
Displacement:
5,938 t light; 6,111 t standard; 6,806 t normal; 7,362 t full load
Dimensions: Length overall / water x beam x draught
457.97 ft / 453.33 ft x 72.18 ft x 14.56 ft (normal load)
139.59 m / 138.18 m x 22.00 m x 4.44 m
Armament:
1 - 5.00" / 127 mm guns in single mounts, 62.50lbs / 28.35kg shells, 1942 Model
Dual purpose gun in a deck mount with hoist
on centreline forward, 1 raised gun
8 - 1.57" / 40.0 mm guns (2x4 guns), 1.95lbs / 0.89kg shells, 1942 Model
Anti-aircraft guns in deck mounts
on side, all aft, all raised mounts - superfiring
4 - 1.57" / 40.0 mm guns (2x2 guns), 1.95lbs / 0.89kg shells, 1942 Model
Anti-aircraft guns in deck mounts
on side, all forward, all raised mounts - superfiring
16 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1942 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 90 lbs / 41 kg
Shells per gun, main battery: 600
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 6,216 shp / 4,637 Kw = 17.00 kts
Range 8,000nm at 15.00 kts
Bunker at max displacement = 1,252 tons
Complement:
374 - 487
Cost:
£1.527 million / $6.109 million
Distribution of weights at normal displacement:
Armament: 11 tons, 0.2%
Machinery: 162 tons, 2.4%
Hull, fittings & equipment: 2,614 tons, 38.4%
Fuel, ammunition & stores: 868 tons, 12.8%
Miscellaneous weights: 3,150 tons, 46.3%
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
19,111 lbs / 8,669 Kg = 305.8 x 5.0 " / 127 mm shells or 3.1 torpedoes
Stability (Unstable if below 1.00): 1.13
Metacentric height 3.9 ft / 1.2 m
Roll period: 15.4 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.02
Seaboat quality (Average = 1.00): 2.00
Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.500
Length to Beam Ratio: 6.28 : 1
'Natural speed' for length: 25.30 kts
Power going to wave formation at top speed: 34 %
Trim (Max stability = 0, Max steadiness = 100): 35
Bow angle (Positive = bow angles forward): 8.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 32.99 ft / 10.06 m
- Forecastle (20%): 23.22 ft / 7.08 m
- Mid (50%): 23.22 ft / 7.08 m
- Quarterdeck (15%): 23.22 ft / 7.08 m
- Stern: 23.22 ft / 7.08 m
- Average freeboard: 24.00 ft / 7.32 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 60.7%
- Above water (accommodation/working, high = better): 268.1%
Waterplane Area: 22,672 Square feet or 2,106 Square metres
Displacement factor (Displacement / loading): 191%
Structure weight / hull surface area: 81 lbs/sq ft or 397 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.91
- Longitudinal: 2.36
- Overall: 1.00
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable, can fire her guns in the heaviest weather
USS Ashland (loaded), USN LSD laid down 1942
Displacement:
5,985 t light; 6,222 t standard; 10,019 t normal; 13,056 t full load
Dimensions: Length overall / water x beam x draught
457.97 ft / 454.15 ft x 72.18 ft x 21.39 ft (normal load)
139.59 m / 138.42 m x 22.00 m x 6.52 m
Armament:
1 - 5.00" / 127 mm guns in single mounts, 62.50lbs / 28.35kg shells, 1942 Model
Dual purpose gun in a deck mount with hoist
on centreline forward, 1 raised gun
8 - 1.57" / 40.0 mm guns (2x4 guns), 1.95lbs / 0.89kg shells, 1942 Model
Anti-aircraft guns in deck mounts
on side, all aft, all raised mounts - superfiring
4 - 1.57" / 40.0 mm guns (2x2 guns), 1.95lbs / 0.89kg shells, 1942 Model
Anti-aircraft guns in deck mounts
on side, all forward, all raised mounts - superfiring
16 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1942 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 90 lbs / 41 kg
Shells per gun, main battery: 600
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 6,216 shp / 4,637 Kw = 16.04 kts
Range 37,315nm at 15.00 kts
Bunker at max displacement = 6,835 tons
Complement:
499 - 650
Cost:
£1.538 million / $6.151 million
Distribution of weights at normal displacement:
Armament: 11 tons, 0.1%
Machinery: 162 tons, 1.6%
Hull, fittings & equipment: 2,661 tons, 26.6%
Fuel, ammunition & stores: 4,034 tons, 40.3%
Miscellaneous weights: 3,150 tons, 31.4%
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
27,612 lbs / 12,525 Kg = 441.8 x 5.0 " / 127 mm shells or 4.8 torpedoes
Stability (Unstable if below 1.00): 1.27
Metacentric height 4.7 ft / 1.4 m
Roll period: 14.0 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.01
Seaboat quality (Average = 1.00): 2.00
Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.500
Length to Beam Ratio: 6.29 : 1
'Natural speed' for length: 25.32 kts
Power going to wave formation at top speed: 33 %
Trim (Max stability = 0, Max steadiness = 100): 35
Bow angle (Positive = bow angles forward): 8.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 27.16 ft / 8.28 m
- Forecastle (20%): 16.39 ft / 4.99 m
- Mid (50%): 16.39 ft / 4.99 m
- Quarterdeck (15%): 16.39 ft / 4.99 m
- Stern: 16.39 ft / 4.99 m
- Average freeboard: 17.25 ft / 5.26 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 41.9%
- Above water (accommodation/working, high = better): 142.1%
Waterplane Area: 22,713 Square feet or 2,110 Square metres
Displacement factor (Displacement / loading): 281%
Structure weight / hull surface area: 84 lbs/sq ft or 408 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.94
- Longitudinal: 1.63
- Overall: 1.00
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable, can fire her guns in the heaviest weather
Actual range: 8000nm @ 15 knots (empty well deck and ballast tanks)
Actual bunker at max displacement 1252 tons
Actual speed 17 knots (empty well deck and ballast tanks)
Well deck = 101.8x13.41m Forward part 16.87 meters from 13.41m wide to minimum of 7.32m. Depth max 2 meters.
Well deck volume 3080 cubic meters (= 3080 tons)
Water in ballast tanks = 2503 tons