WesWorld

Perhaps, but I figured the lake boats could trade speed, range, and firepower for misc. weight to a degree that might not work for coastal chasers.

I guess that's fair enough.

My gut instinct on the subchaser is that the 105mm gun feels... too large for the displacement. Most ships I'm familiar with in that size bracket - the USN subchasers coming to mind - only had a 3" or 40mm deck gun. They might be fine, but they just... "feel over-armed" to me.

Valid concern. I'll see if anybody else wants to weigh in there.

Quoted

Originally posted by The Rock Doctor
Valid concern. I'll see if anybody else wants to weigh in there.

Don't look at me! I've tried putting a 7.5" gun on a 500t trawler. And I have a design somewhere for a 1500t ship with an 18" gun, if memory serves.
[size=1](everything should have a way of putting big holes in other things. i have a sickness.)[/size]

Most of my subchasers are modeled on historical American designs which have a similar displacement. All mount 3" or the newer 2.95" guns. If I were to ever consider mounting a larger gun I'd want a larger hull.

German boats carried 10.5 or 8.8 guns in WorldWar too.
Those where SB-boats or AF-boats. betwin 30-80 metre.

Been a while since I've designed a submarine, so feedback would be appreciated. This here's a small ocean-going boat intended to have the range to wander up or down the west coast of South America and generally make a nuisance of itself.


P-6, Peruvian Submarine, laid down 1941

Displacement:
750 t light; 772 t standard; 858 t normal; 927 t full load

Dimensions: Length overall / water x beam x draught
181.43 ft / 181.43 ft x 24.61 ft x 13.45 ft (normal load)
55.30 m / 55.30 m x 7.50 m x 4.10 m

Armament:
1 - 4.13" / 105 mm guns in single mounts, 35.32lbs / 16.02kg shells, 1941 Model
Dual purpose gun in deck mount
on centreline forward
1 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1941 Model
Anti-aircraft gun in deck mount
on centreline aft
1 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1941 Model
Machine gun in deck mount
on centreline aft
Weight of broadside 36 lbs / 16 kg
Shells per gun, main battery: 250
6 - 21.0" / 533 mm submerged torpedo tubes

Machinery:
Diesel Internal combustion engines plus batteries,
Electric cruising motors plus geared drives, 2 shafts, 3,000 shp / 2,238 Kw = 17.85 kts
Range 8,000nm at 10.00 kts (Bunkerage = 155 tons)

Complement:
79 - 103

Cost:
£0.254 million / $1.016 million

Distribution of weights at normal displacement:
Armament: 4 tons, 0.5 %
Machinery: 79 tons, 9.2 %
Hull, fittings & equipment: 466 tons, 54.3 %
Fuel, ammunition & stores: 108 tons, 12.6 %
Miscellaneous weights: 200 tons, 23.3 %
-170 t: Ballast tanks (=19.8% of normal displacement)
-20 t: 10 reload torpedoes (8 F, 2 A) or equivalent in mines
-5 t: Sonar
-5 t: Weight Reserve

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
230 lbs / 104 Kg = 6.5 x 4.1 " / 105 mm shells or 0.2 torpedoes
Stability (Unstable if below 1.00): 1.07
Metacentric height 0.7 ft / 0.2 m
Roll period: 12.3 seconds
Steadiness - As gun platform (Average = 50 %): 0 %
- Recoil effect (Restricted arc if above 1.00): 0.00
Seaboat quality (Average = 1.00): 0.00

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.500
Length to Beam Ratio: 7.37 : 1
'Natural speed' for length: 13.47 kts
Power going to wave formation at top speed: 60 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 0.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 0.00 ft / 0.00 m
- Forecastle (20 %): 0.00 ft / 0.00 m
- Mid (50 %): 0.00 ft / 0.00 m
- Quarterdeck (15 %): 0.00 ft / 0.00 m
- Stern: 0.00 ft / 0.00 m
- Average freeboard: 0.00 ft / 0.00 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 139.0 %
- Above water (accommodation/working, high = better): 0.0 %
Waterplane Area: 2,974 Square feet or 276 Square metres
Displacement factor (Displacement / loading): 218 %
Structure weight / hull surface area: 112 lbs/sq ft or 545 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 3.48
- Longitudinal: 2.52
- Overall: 2.74
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is extremely poor
Ship has quick, lively roll, not a steady gun platform
Caution: Lacks seaworthiness - very limited seakeeping ability

I fear I have never designed a submarine in Springsharp myself, but what I see seems reasonable enough to the untrained eye.

It has a reasonable size, armament and radius of action to be combat-worthy without being too large. It certainly would be a headache for the neighbors (which I suspect would be the purpose).

Good to know - what are you using to design subs with?

Quoted

Originally posted by The Rock Doctor
Good to know - what are you using to design subs with?

It's a program called "Brockpaine"

Looks good to me. Comparing with similar sized designs I've done it looks fine.

Catch-up time.

This is the trawler Rio Maranon, which was converted into service as a fisheries research vessel. She's got a limited armament for policing and wartime purposes.

Enter ship name, Enter country Enter ship type laid down 1938

Displacement:
1,021 t light; 1,051 t standard; 1,199 t normal; 1,317 t full load

Dimensions: Length overall / water x beam x draught
204.35 ft / 196.85 ft x 36.09 ft x 9.84 ft (normal load)
62.29 m / 60.00 m x 11.00 m x 3.00 m

Armament:
1 - 4.13" / 105 mm guns in single mounts, 35.32lbs / 16.02kg shells, 1938 Model
Dual purpose gun in a deck mount with hoist
on centreline forward, 1 raised gun
1 - 1.46" / 37.0 mm guns in single mounts, 1.55lbs / 0.70kg shells, 1938 Model
Anti-aircraft gun in deck mount
on centreline aft, 1 raised gun
2 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1938 Model
Anti-aircraft guns in deck mounts
on side, all amidships, all raised mounts - superfiring
Weight of broadside 37 lbs / 17 kg
Shells per gun, main battery: 300

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.98" / 25 mm 0.39" / 10 mm 0.98" / 25 mm
2nd: 0.79" / 20 mm 0.39" / 10 mm -
3rd: 0.39" / 10 mm - -

Machinery:
Coal fired boilers, complex reciprocating steam engines,
Geared drive, 2 shafts, 4,000 ihp / 2,984 Kw = 17.92 kts
Range 6,000nm at 10.00 kts (Bunkerage = 265 tons)

Complement:
101 - 132

Cost:
£0.416 million / $1.664 million

Distribution of weights at normal displacement:
Armament: 5 tons, 0.4 %
Armour: 3 tons, 0.2 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 3 tons, 0.2 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 244 tons, 20.3 %
Hull, fittings & equipment: 381 tons, 31.8 %
Fuel, ammunition & stores: 178 tons, 14.8 %
Miscellaneous weights: 389 tons, 32.5 %
-105 t: Accomodation for 33 scientists and/or marine constables
-100 t: Trawl gear
-100 t: Labs and workspace
-74 t: Weight reserve/deck cargo
-10 t: Rails, Throwers, and 30 depth charges

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1,490 lbs / 676 Kg = 42.2 x 4.1 " / 105 mm shells or 0.6 torpedoes
Stability (Unstable if below 1.00): 1.16
Metacentric height 1.4 ft / 0.4 m
Roll period: 12.7 seconds
Steadiness - As gun platform (Average = 50 %): 51 %
- Recoil effect (Restricted arc if above 1.00): 0.06
Seaboat quality (Average = 1.00): 1.64

Hull form characteristics:
Hull has raised forecastle
Block coefficient: 0.600
Length to Beam Ratio: 5.45 : 1
'Natural speed' for length: 14.03 kts
Power going to wave formation at top speed: 64 %
Trim (Max stability = 0, Max steadiness = 100): 31
Bow angle (Positive = bow angles forward): 10.00 degrees
Stern overhang: 3.28 ft / 1.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 23.95 ft / 7.30 m
- Forecastle (20 %): 21.00 ft / 6.40 m (13.12 ft / 4.00 m aft of break)
- Mid (50 %): 11.81 ft / 3.60 m
- Quarterdeck (25 %): 13.12 ft / 4.00 m
- Stern: 15.09 ft / 4.60 m
- Average freeboard: 14.82 ft / 4.52 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 104.8 %
- Above water (accommodation/working, high = better): 122.2 %
Waterplane Area: 5,196 Square feet or 483 Square metres
Displacement factor (Displacement / loading): 131 %
Structure weight / hull surface area: 43 lbs/sq ft or 209 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.82
- Longitudinal: 5.43
- Overall: 1.00
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

Really large and fast for a 1940s trawler...