WesWorld

These ships are to be laid down Q4 of 1930.

The Gruno and Tijgerhaai are gunboats, primarily for inter-island patrol and trade protection in the DEI. Opposing forces would be hypothetical raiding destroyers or less.

The Humboldt is an updated version of the 1922 seaplane tender (which will be in the next post...)
The DeGroot is a new Seaplane carrier class.

I had troubles figuring out how much the seaplane vessels could "hold". Flight deck is not applicable, the springstyle notes on GRT require loaded submergence, which doesn't seem to show up in the report. So I punted.
The Humboldt... I kept the rear end clear and hoped 4 floatplanes could fit there.
The DeGroot wound up with 4,000misc tons for seaplanes. The Jane's notes on the IJN Notoro indicates that 16 was the maximum stowage and she was 8,000 tons gross, so I used half that for the max seaplane load.

Any pointers on those issues?

====================
Humboldt, Netherlands Seaplane Tender laid down 1930

Displacement:
1,910 t light; 1,979 t standard; 2,565 t normal; 3,033 t full load

Dimensions: Length overall / water x beam x draught
315.01 ft / 301.84 ft x 41.01 ft x 14.11 ft (normal load)
96.01 m / 92.00 m x 12.50 m x 4.30 m

Armament:
4 - 3.94" / 100 mm guns (2x2 guns), 30.51lbs / 13.84kg shells, 1930 Model
Dual purpose guns in deck mounts with hoists
on centreline, all forward, 1 raised mount - superfiring
4 - 1.57" / 40.0 mm guns (1x4 guns), 1.94lbs / 0.88kg shells, 1930 Model
Anti-aircraft guns in deck mount
on centreline aft, all raised guns - superfiring
8 - 1.57" / 40.0 mm guns (4x2 guns), 1.94lbs / 0.88kg shells, 1930 Model
Anti-aircraft guns in deck mounts
on side ends, evenly spread
Weight of broadside 145 lbs / 66 kg
Shells per gun, main battery: 200

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 1.18" / 30 mm 195.01 ft / 59.44 m 9.84 ft / 3.00 m
Ends: Unarmoured
Main Belt covers 99 % of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.18" / 30 mm 0.79" / 20 mm 0.98" / 25 mm
2nd: 0.59" / 15 mm - -
3rd: 0.59" / 15 mm - -

- Armour deck: 0.59" / 15 mm, Conning tower: 0.79" / 20 mm

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 7,557 shp / 5,638 Kw = 20.00 kts
Range 10,000nm at 15.00 kts
Bunker at max displacement = 1,053 tons

Complement:
179 - 234

Cost:
£0.478 million / $1.910 million

Distribution of weights at normal displacement:
Armament: 18 tons, 0.7 %
Armour: 203 tons, 7.9 %
- Belts: 97 tons, 3.8 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 11 tons, 0.4 %
- Armour Deck: 91 tons, 3.6 %
- Conning Tower: 3 tons, 0.1 %
Machinery: 229 tons, 8.9 %
Hull, fittings & equipment: 805 tons, 31.4 %
Fuel, ammunition & stores: 654 tons, 25.5 %
Miscellaneous weights: 655 tons, 25.5 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
4,462 lbs / 2,024 Kg = 146.2 x 3.9 " / 100 mm shells or 1.5 torpedoes
Stability (Unstable if below 1.00): 1.05
Metacentric height 1.5 ft / 0.4 m
Roll period: 14.3 seconds
Steadiness - As gun platform (Average = 50 %): 75 %
- Recoil effect (Restricted arc if above 1.00): 0.14
Seaboat quality (Average = 1.00): 1.59

Hull form characteristics:
Hull has raised forecastle
Block coefficient: 0.514
Length to Beam Ratio: 7.36 : 1
'Natural speed' for length: 17.37 kts
Power going to wave formation at top speed: 53 %
Trim (Max stability = 0, Max steadiness = 100): 47
Bow angle (Positive = bow angles forward): 18.00 degrees
Stern overhang: 6.56 ft / 2.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 20.34 ft / 6.20 m
- Forecastle (20 %): 20.34 ft / 6.20 m (12.34 ft / 3.76 m aft of break)
- Mid (50 %): 12.34 ft / 3.76 m
- Quarterdeck (30 %): 12.34 ft / 3.76 m
- Stern: 12.34 ft / 3.76 m
- Average freeboard: 13.94 ft / 4.25 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 63.4 %
- Above water (accommodation/working, high = better): 109.7 %
Waterplane Area: 8,354 Square feet or 776 Square metres
Displacement factor (Displacement / loading): 175 %
Structure weight / hull surface area: 59 lbs/sq ft or 288 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.97
- Longitudinal: 2.32
- Overall: 1.06
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

The USN's Barnegat seaplane tender was the starting point.

25 tons are true misc.
5 ton meteorological .
500 tons are given over to seaplane support.
It is presumed 4 float planes and 1 catapult are embarked and others can be tended (125 tons).

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DeGroot, Netherlands Seaplane Carrier laid down 1930

Displacement:
7,994 t light; 8,230 t standard; 9,776 t normal; 11,013 t full load

Dimensions: Length overall / water x beam x draught
470.26 ft / 452.76 ft x 62.34 ft (Bulges 72.18 ft) x 17.72 ft (normal load)
143.34 m / 138.00 m x 19.00 m (Bulges 22.00 m) x 5.40 m

Armament:
4 - 4.92" / 125 mm guns in single mounts, 59.59lbs / 27.03kg shells, 1930 Model
Dual purpose guns in deck mounts with hoists
on side ends, evenly spread
16 - 2.24" / 57.0 mm guns (8x2 guns), 5.65lbs / 2.56kg shells, 1930 Model
Anti-aircraft guns in deck mounts with hoists
on side, evenly spread
4 - 0.52" / 13.2 mm guns in single mounts, 0.07lbs / 0.03kg shells, 1930 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 329 lbs / 149 kg
Shells per gun, main battery: 200

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 0.79" / 20 mm 294.29 ft / 89.70 m 9.84 ft / 3.00 m
Ends: Unarmoured
Main Belt covers 100 % of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.59" / 15 mm 0.31" / 8 mm 0.39" / 10 mm
2nd: 0.59" / 15 mm 0.31" / 8 mm 0.39" / 10 mm
3rd: 0.59" / 15 mm - -

- Armour deck: 0.39" / 10 mm, Conning tower: 0.79" / 20 mm

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 16,696 shp / 12,455 Kw = 21.00 kts
Range 13,000nm at 15.00 kts
Bunker at max displacement = 2,783 tons

Complement:
491 - 639

Cost:
£1.611 million / $6.443 million

Distribution of weights at normal displacement:
Armament: 41 tons, 0.4 %
Armour: 277 tons, 2.8 %
- Belts: 98 tons, 1.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 15 tons, 0.2 %
- Armour Deck: 155 tons, 1.6 %
- Conning Tower: 8 tons, 0.1 %
Machinery: 506 tons, 5.2 %
Hull, fittings & equipment: 2,670 tons, 27.3 %
Fuel, ammunition & stores: 1,783 tons, 18.2 %
Miscellaneous weights: 4,500 tons, 46.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
14,622 lbs / 6,633 Kg = 245.4 x 4.9 " / 125 mm shells or 2.5 torpedoes
Stability (Unstable if below 1.00): 1.07
Metacentric height 2.8 ft / 0.9 m
Roll period: 18.1 seconds
Steadiness - As gun platform (Average = 50 %): 76 %
- Recoil effect (Restricted arc if above 1.00): 0.05
Seaboat quality (Average = 1.00): 1.62

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.591
Length to Beam Ratio: 6.27 : 1
'Natural speed' for length: 24.99 kts
Power going to wave formation at top speed: 49 %
Trim (Max stability = 0, Max steadiness = 100): 47
Bow angle (Positive = bow angles forward): 18.00 degrees
Stern overhang: 9.84 ft / 3.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 23.59 ft / 7.19 m
- Forecastle (20 %): 23.00 ft / 7.01 m
- Mid (50 %): 14.99 ft / 4.57 m
- Quarterdeck (15 %): 14.99 ft / 4.57 m
- Stern: 14.99 ft / 4.57 m
- Average freeboard: 17.84 ft / 5.44 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 70.9 %
- Above water (accommodation/working, high = better): 139.3 %
Waterplane Area: 21,329 Square feet or 1,982 Square metres
Displacement factor (Displacement / loading): 160 %
Structure weight / hull surface area: 85 lbs/sq ft or 415 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.97
- Longitudinal: 1.42
- 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

The DeGroot class Seaplane carriers have
120 tons 2 compressed air catapults with 2 floatplanes, and 40 DCs in an armored magazine.
5 ton meteorological station
15 ton lighter/net tender
160 ton harbor-level torpedo netting
100 tons extra berthing.
100 tons of general purpose maintenance forges.
and 4,000 tons dedicated to seaplanes and seaplane support. Normal air suite is 8 seaplanes or 16 floatplanes.

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Tijgerhaai, Netherlands Kanoneerbooten laid down 1930

Displacement:
1,926 t light; 2,045 t standard; 2,463 t normal; 2,797 t full load

Dimensions: Length overall / water x beam x draught
376.06 ft / 360.89 ft x 39.70 ft x 11.48 ft (normal load)
114.62 m / 110.00 m x 12.10 m x 3.50 m

Armament:
8 - 4.92" / 125 mm guns (4x2 guns), 59.59lbs / 27.03kg shells, 1930 Model
Dual purpose guns in deck mounts with hoists
on centreline ends, evenly spread, 2 raised mounts - superfiring
8 - 1.57" / 40.0 mm guns (4x2 guns), 1.95lbs / 0.88kg shells, 1930 Model
Anti-aircraft guns in deck mounts
on centreline, all aft, all raised mounts - superfiring
4 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1930 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 493 lbs / 224 kg
Shells per gun, main battery: 250

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 1.18" / 30 mm 196.85 ft / 60.00 m 9.84 ft / 3.00 m
Ends: Unarmoured
Main Belt covers 84 % of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.18" / 30 mm 0.79" / 20 mm 0.98" / 25 mm
2nd: 0.59" / 15 mm - -

- Armour deck: 0.59" / 15 mm, Conning tower: 0.79" / 20 mm

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 12,174 shp / 9,082 Kw = 24.00 kts
Range 8,000nm at 15.00 kts
Bunker at max displacement = 753 tons

Complement:
174 - 227

Cost:
£0.714 million / $2.858 million

Distribution of weights at normal displacement:
Armament: 62 tons, 2.5 %
Armour: 240 tons, 9.7 %
- Belts: 99 tons, 4.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 27 tons, 1.1 %
- Armour Deck: 111 tons, 4.5 %
- Conning Tower: 3 tons, 0.1 %
Machinery: 369 tons, 15.0 %
Hull, fittings & equipment: 1,205 tons, 48.9 %
Fuel, ammunition & stores: 537 tons, 21.8 %
Miscellaneous weights: 50 tons, 2.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
4,714 lbs / 2,138 Kg = 79.1 x 4.9 " / 125 mm shells or 1.3 torpedoes
Stability (Unstable if below 1.00): 1.16
Metacentric height 1.6 ft / 0.5 m
Roll period: 13.0 seconds
Steadiness - As gun platform (Average = 50 %): 72 %
- Recoil effect (Restricted arc if above 1.00): 0.56
Seaboat quality (Average = 1.00): 1.45

Hull form characteristics:
Hull has raised forecastle
and transom stern
Block coefficient: 0.524
Length to Beam Ratio: 9.09 : 1
'Natural speed' for length: 21.78 kts
Power going to wave formation at top speed: 55 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 22.00 degrees
Stern overhang: 6.56 ft / 2.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 21.29 ft / 6.49 m
- Forecastle (20 %): 21.29 ft / 6.49 m (13.29 ft / 4.05 m aft of break)
- Mid (50 %): 13.29 ft / 4.05 m
- Quarterdeck (15 %): 13.29 ft / 4.05 m
- Stern: 13.29 ft / 4.05 m
- Average freeboard: 14.89 ft / 4.54 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 72.2 %
- Above water (accommodation/working, high = better): 147.7 %
Waterplane Area: 10,154 Square feet or 943 Square metres
Displacement factor (Displacement / loading): 162 %
Structure weight / hull surface area: 73 lbs/sq ft or 358 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.07
- Longitudinal: 2.39
- Overall: 1.16
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
Good seaboat, rides out heavy weather easily

Based on a cut down Selfridge class USN DD.

Misc wieght includes
4 for small arms locker
6 for an extra director and provision for indirect bombardment.
40 undefined.

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Gruno, Netherlands KLK Kanoneerbooten laid down 1930

Displacement:
499 t light; 538 t standard; 560 t normal; 577 t full load

Dimensions: Length overall / water x beam x draught
185.20 ft / 172.24 ft x 27.89 ft x 9.19 ft (normal load)
56.45 m / 52.50 m x 8.50 m x 2.80 m

Armament:
4 - 4.92" / 125 mm guns (2x2 guns), 59.59lbs / 27.03kg shells, 1926 Model
Quick firing guns in deck mounts
on centreline ends, evenly spread
4 - 1.57" / 40.0 mm guns (2x2 guns), 1.95lbs / 0.88kg shells, 1928 Model
Anti-aircraft guns in deck mounts
on side, all amidships, 1 raised mount - superfiring
4 - 0.52" / 13.2 mm guns (2x2 guns), 0.07lbs / 0.03kg shells, 1928 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 246 lbs / 112 kg
Shells per gun, main battery: 200
2 - 21.0" / 533.4 mm submerged torpedo tubes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 1.97" / 50 mm 112.37 ft / 34.25 m 13.12 ft / 4.00 m
Ends: 0.59" / 15 mm 59.88 ft / 18.25 m 13.12 ft / 4.00 m
Main Belt covers 100 % of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.18" / 30 mm 0.59" / 15 mm -
2nd: 0.59" / 15 mm - -
3rd: 0.31" / 8 mm - -

- Armour deck: 0.53" / 14 mm, Conning tower: 1.97" / 50 mm

Machinery:
Diesel Internal combustion motors,
Electric cruising motors plus geared drives, 2 shafts, 1,239 shp / 925 Kw = 16.00 kts
Range 4,000nm at 8.00 kts
Bunker at max displacement = 39 tons

Complement:
56 - 74

Cost:
£0.203 million / $0.813 million

Distribution of weights at normal displacement:
Armament: 31 tons, 5.5 %
Armour: 188 tons, 33.6 %
- Belts: 143 tons, 25.5 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 11 tons, 2.0 %
- Armour Deck: 31 tons, 5.6 %
- Conning Tower: 3 tons, 0.5 %
Machinery: 38 tons, 6.7 %
Hull, fittings & equipment: 225 tons, 40.1 %
Fuel, ammunition & stores: 61 tons, 10.9 %
Miscellaneous weights: 18 tons, 3.2 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
911 lbs / 413 Kg = 15.3 x 4.9 " / 125 mm shells or 0.6 torpedoes
Stability (Unstable if below 1.00): 1.23
Metacentric height 1.1 ft / 0.3 m
Roll period: 11.3 seconds
Steadiness - As gun platform (Average = 50 %): 76 %
- Recoil effect (Restricted arc if above 1.00): 0.40
Seaboat quality (Average = 1.00): 1.85

Hull form characteristics:
Hull has raised forecastle
and transom stern
Block coefficient: 0.444
Length to Beam Ratio: 6.18 : 1
'Natural speed' for length: 15.76 kts
Power going to wave formation at top speed: 55 %
Trim (Max stability = 0, Max steadiness = 100): 41
Bow angle (Positive = bow angles forward): 18.00 degrees
Stern overhang: 6.56 ft / 2.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 19.69 ft / 6.00 m
- Forecastle (20 %): 14.44 ft / 4.40 m (9.19 ft / 2.80 m aft of break)
- Mid (50 %): 9.19 ft / 2.80 m
- Quarterdeck (15 %): 9.19 ft / 2.80 m
- Stern: 9.19 ft / 2.80 m
- Average freeboard: 10.66 ft / 3.25 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 84.5 %
- Above water (accommodation/working, high = better): 99.0 %
Waterplane Area: 3,167 Square feet or 294 Square metres
Displacement factor (Displacement / loading): 106 %
Structure weight / hull surface area: 41 lbs/sq ft or 201 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.87
- Longitudinal: 4.82
- Overall: 1.03
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

The vessel is based on the 1913 Netherlands gunboat, Gruno (533tons).

The ship has been slightly upgunned (4.7" ->4.9", 2x20mm->4x40mm)and a pair of submerged bow torpedoes included.

Deck armor is 15mm over the vitals, and 7.5mm over the ends.

8 tons of Misc represent electric drive and housing the props in tunnels.
The remaining 10 tons includes:
4 for two 21" torpedoes (no reloads),
6 for an extra director and provision for indirect bombardment.

The seaplane carriers and lighter "coastal" forces will be especially useful in the NEI.

I would reccomend a run of fast (20+knots) MSWs and MLs at some point in the future, as well.

One of the reasons I needed to figure out just what the existing ML/MSWs (old aux) were was so I could get some idea of when they need refitting/replacing. You are quite right that's something "on the plate".

Right now Q1, 1931 is stalled as I can't decide if I want to invest some of Type 0 slips and a drydock to dedicate to small craft production/maintenance, or to invest that tonnage in...more small craft.

RAM left me lots of drydocks and slips of all the other size ranges, so I've just been using bigger than I have to, but I am filling up. At one point it looked like I may build a 52.5m Gruno in a Class 4 slip ! I had this debate back in Q1/30 also

Of course I want more seaplane and normal carriers, the new BBs, replacing the Z13s, doing something about the Amsterdams and Palembangs CLs... hmm maybe slips in 1932...

Type 0 slips are cheap and I myself have dedicated a few to producing MTB's and Motor launches. It wouldn't hurt to build a few more while still dedicating some tonnage to building the actual ships.

I think the problem is that I want do it all at once, and that doesn't work so well

Right now, my tenative 1931 plans call for 4 factories to produce 2 type 0 slips and 1 type 0 drydock. I also want to start develop naval facilities at Paramaribo and Matadi, with at least 0 slips for local productions.

I should toy with just doing the 2 slips and discard or wait on the drydock.
...drydock.
So- any rules for floating drydocks?

Edit : Sidenote- the "6 for an extra director and provision for indirect bombardment" on the Gruno and Tijgerhaai comes from a Wikipedia note on the 1926 gunboat Flores - "their main asset was an advanced fire control system that made them very accurate in bombarding shore targets "- which I'm trying to establish storyline wise.

As for the Minelayer, Alikchi spurred me a bit and I tried several varients. I wanted to keep it small, but the mine loadouts were poor after the other necessary elements added.

The Minelayers are the greater concern, as the coastal minesweepers I'm building will at least serve defensively, and I have 20 of the old sweepers.

So- prototype
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ML-2, Netherlands Mijenlegger laid down 1930

Displacement:
1,692 t light; 1,748 t standard; 1,908 t normal; 2,035 t full load

Dimensions: Length overall / water x beam x draught
341.04 ft / 328.08 ft x 37.73 ft x 10.01 ft (normal load)
103.95 m / 100.00 m x 11.50 m x 3.05 m

Armament:
2 - 3.94" / 100 mm guns (1x2 guns), 30.51lbs / 13.84kg shells, 1926 Model
Dual purpose guns in a deck mount with hoist
on centreline forward
2 - 3.94" / 100 mm guns (1x2 guns), 30.51lbs / 13.84kg shells, 1928 Model
Dual purpose guns in a deck mount with hoist
on centreline amidships
4 - 1.57" / 40.0 mm guns in single mounts, 1.95lbs / 0.89kg shells, 1928 Model
Anti-aircraft guns in deck mounts
on side, all forward
4 - 0.52" / 13.2 mm guns in single mounts, 0.07lbs / 0.03kg shells, 1930 Model
Machine guns in deck mounts
on side, all forward, all raised mounts - superfiring
8 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1930 Model
Anti-aircraft guns in deck mounts
on side, evenly spread
Weight of broadside 132 lbs / 60 kg
Shells per gun, main battery: 200

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.18" / 30 mm 0.79" / 20 mm 0.98" / 25 mm
2nd: 1.18" / 30 mm 0.79" / 20 mm 0.98" / 25 mm
3rd: 0.59" / 15 mm - -
4th: 0.31" / 8 mm - -

- Conning tower: 0.79" / 20 mm

Machinery:
Diesel Internal combustion motors,
Electric cruising motors plus geared drives, 2 shafts, 10,886 shp / 8,121 Kw = 24.00 kts
Range 8,500nm at 10.00 kts
Bunker at max displacement = 287 tons

Complement:
143 - 187

Cost:
£0.499 million / $1.995 million

Distribution of weights at normal displacement:
Armament: 17 tons, 0.9 %
Armour: 13 tons, 0.7 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 11 tons, 0.6 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 3 tons, 0.1 %
Machinery: 330 tons, 17.3 %
Hull, fittings & equipment: 866 tons, 45.4 %
Fuel, ammunition & stores: 215 tons, 11.3 %
Miscellaneous weights: 467 tons, 24.5 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
3,234 lbs / 1,467 Kg = 106.0 x 3.9 " / 100 mm shells or 0.9 torpedoes
Stability (Unstable if below 1.00): 1.01
Metacentric height 1.2 ft / 0.4 m
Roll period: 14.6 seconds
Steadiness - As gun platform (Average = 50 %): 76 %
- Recoil effect (Restricted arc if above 1.00): 0.22
Seaboat quality (Average = 1.00): 1.52

Hull form characteristics:
Hull has rise forward of midbreak
and transom stern
Block coefficient: 0.539
Length to Beam Ratio: 8.70 : 1
'Natural speed' for length: 20.81 kts
Power going to wave formation at top speed: 58 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 18.00 degrees
Stern overhang: 6.56 ft / 2.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 19.69 ft / 6.00 m
- Forecastle (20 %): 19.69 ft / 6.00 m
- Mid (50 %): 19.69 ft / 6.00 m (11.68 ft / 3.56 m aft of break)
- Quarterdeck (15 %): 11.68 ft / 3.56 m
- Stern: 11.68 ft / 3.56 m
- Average freeboard: 15.68 ft / 4.78 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 90.2 %
- Above water (accommodation/working, high = better): 182.3 %
Waterplane Area: 8,899 Square feet or 827 Square metres
Displacement factor (Displacement / loading): 150 %
Structure weight / hull surface area: 57 lbs/sq ft or 279 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.95
- Longitudinal: 3.07
- Overall: 1.06
Hull space for machinery, storage, compartmentation is adequate
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

Trying to provide for a high-speed self-escorting minelayer.

I'm envisioning
The gun layout is one twin 100mm mount forward of the superstructure, then a funnel with the second twin 100mm mount just aft of the funnel, just above the step in the hull. This should give a decent arc of fire. The rear half of the ship is given over to the mine deck.

Of the miscellaneous weight, 67 is for the electric motors (for silent night ops), 50 for true miscellaneous (sounding gear, magnetic detectors, night vision gear, etc), and 350 for mines.

Size (Max): 155 t
Length (Total): 41,0 m
Length (Waterline):
Beam: 5,8 m
Draft: 1,7 m
Crew:
Weapons
3,7 cm Flak: 1
2 cm MG: 3
8,6 cm Missle Launcher "Föhn": 1
Engines
Voith-Schneider Propellers: 2
Engines: 2
Type: MAN 8-cylinder diesel
Performance
Total Performance: 1800 shp
Speed: 19 kn
Range:

For a small minelayer.



For a very small Italian minelayer. Only 15tons but 4 mines and a 47mm gun.

No on the floating drydocks. Got to be paid the same as for normal ones.

De Groot is a bit large, but it depends what you want.



RN Giuseppe Miraglia of 5000tons normal with provisions for 20 aircraft and 2 catapults. Quite a large conversion however. Maybe something like HMS Engadine

Quoted

For a very small Italian minelayer. Only 15tons but 4 mines and a 47mm gun.

Does it have a bit of speed like the MAS? Or is it a slowere vessel?

About 26knts max IIRC.

The small minelayer will definitely fit a foreseen niche, and I was planning on turning to my Italian allies for their small craft experience, at least to get started. I want to build up a reasonable number of patrol craft and coastal minesweepers with my <75,<200 tonnages, so MTB/light ML are looking like 1932-33.

Thanks for the link on Engadine. From it’s size and the 4 Short 184s, it’s a good analog for the Humbold class AVP’s and supports my guess of 4 floatplanes for that.

I like the Giuseppe Miraglia, and those do look like full fledged seaplanes, not floatplanes. I was trying to find reference numbers in my Jane’s of WW2. Like I said the best guide I could find was the Notoro with 8000GRT and 16 max seaplanes.

And…that word “conversion” made me wonder why I’m paying full price for the DeGroots- I don’t think they have any specialty bits.

1) For Seaplane carriers- folks doing “purchase” and conversions or new builds?
2) Any idea on GRT/Seaplanes carried? Bigger than Bi-planes.
3) Rough dimensions/speed for Giuseppe Miraglia?

Details on Giuseppe Miraglia here

Pieno Carico is deep load. Everything else is straightforward.

They are flying boats on Miraglia. Macchi 18 and 71 types. Have a look in the Italian section of the encyclopaedia for details. Space for 20 aircraft. She also operated IMAM Ro.41 seaplane and Re 2000 landplane. Served as a aircraft ferry as well.





IIRC I did 50% of light displacement to account for the catapults, guns, workshops and superstructure additions.

Well I tried a couple sims of Guiseppe -springsharp and springstyle. My Jane's has a nice broadside photo I used to guess freeboard. Stats are like that of the page you linked.

Like the problem I was having with frieghters, I needed to trim heavily to take any wieght as it appeared to add it above decks.

Untrimmed = can take 210 tons Misc wieght prior to Stab <1. 0
Trimmed = Or can trim down 13 with 2680 misc + quick & lively roll.
Trimmed = Or can trim to 20 with 2500 + excellent seaboat.

SQRT (2500) = 50, so that formula overestimates.
LxB/750 =24, so it fits there to.

For DeGroot the same numbers got
LxB/750 = 37.5 MIN misc= 1406.25
Sqrt(4000) = 63

So I'm baffled as to why the IJN ships would be listed as having such light loads.

I think I will re-work Degroot to trim off some misc weight and then overall size, all I really want is 16-24 seaplanes. If I provide for 36, that will allow for larger seaplanes.

One thing to consider is that armor belts on many of these designs will cause them to be restricted by treaty. That said, I think there's value in all aspects of what you're proposing here.

My thoughts on Type 0 facilities is that slips are worthwhile. Type 0 drydocks are another matter. My own logic there is that a vessel in this size category is delicate and less likely to survive battle damage. It's also not that much more expensive or time-consuming to build a replacement than to repair a badly damaged unit, especially when one considers the cost of the drydock compared to the cost of the vessel.

I'm happy with my three Type 0 slips - could even use one or two more - but my sole Type 0 drydock is slated for improvement into a Type 1.

The Japanese seaplane tenders could operate H6Ks and H8Ks. Very large aircraft. They were also considerably faster and heavily armed. Probably more suited to extended operations.



You could possibly use belt amour to simulate weights in hold as it places the weight more or less at the waterline. But for seaplane carriers, the weight is all high anyway.

Quoted

Originally posted by The Rock Doctor
One thing to consider is that armor belts on many of these designs will cause them to be restricted by treaty. That said, ....
I'm happy with my three Type 0 slips - could even use one or two more - but my sole Type 0 drydock is slated for improvement into a Type 1.

Ooooohhh. Thanks for drawing my attention back to G(I)(c). The <2000 ton vessels are fine, DeGroot definitely is over the line- armor on hull, too fast, and 2 Catapults mean she's can only have 10 aircraft.

Hmm back to 8 seaplanes?

RA- Right now I have the Dutch down as using the 1927 Fokker T.IV, which looks big, but I have no clue as to scale regarding either the Italian aircraft or the Japanese. Any ideas?

Unless conning tower armor counts, I think she's compliant now.

DeGroot, Netherlands Seaplane Carrier laid down 1930

Displacement:
4,924 t light; 5,098 t standard; 6,641 t normal; 7,875 t full load

Dimensions: Length overall / water x beam x draught
410.65 ft / 393.70 ft x 59.06 ft (Bulges 67.26 ft) x 16.08 ft (normal load)
125.17 m / 120.00 m x 18.00 m (Bulges 20.50 m) x 4.90 m

Armament:
4 - 4.92" / 125 mm guns in single mounts, 59.59lbs / 27.03kg shells, 1930 Model
Dual purpose guns in deck mounts with hoists
on side ends, evenly spread
16 - 2.24" / 57.0 mm guns (8x2 guns), 5.65lbs / 2.56kg shells, 1930 Model
Anti-aircraft guns in deck mounts with hoists
on side, evenly spread
4 - 0.52" / 13.2 mm guns in single mounts, 0.07lbs / 0.03kg shells, 1930 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 329 lbs / 149 kg
Shells per gun, main battery: 200

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Ends: 1.57" / 40 mm 32.81 ft / 10.00 m 8.01 ft / 2.44 m
360.89 ft / 110.00 m Unarmoured ends

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.59" / 15 mm 0.31" / 8 mm 0.39" / 10 mm
2nd: 0.59" / 15 mm 0.31" / 8 mm 0.39" / 10 mm
3rd: 0.59" / 15 mm - -

- Conning tower: 0.79" / 20 mm

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 11,142 shp / 8,312 Kw = 20.00 kts
Range 16,650nm at 15.00 kts
Bunker at max displacement = 2,777 tons

Complement:
367 - 478

Cost:
£1.063 million / $4.251 million

Distribution of weights at normal displacement:
Armament: 41 tons, 0.6 %
Armour: 37 tons, 0.6 %
- Belts: 15 tons, 0.2 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 16 tons, 0.2 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 6 tons, 0.1 %
Machinery: 338 tons, 5.1 %
Hull, fittings & equipment: 2,008 tons, 30.2 %
Fuel, ammunition & stores: 1,717 tons, 25.9 %
Miscellaneous weights: 2,500 tons, 37.6 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
12,604 lbs / 5,717 Kg = 211.5 x 4.9 " / 125 mm shells or 2.5 torpedoes
Stability (Unstable if below 1.00): 1.12
Metacentric height 2.8 ft / 0.9 m
Roll period: 16.9 seconds
Steadiness - As gun platform (Average = 50 %): 88 %
- Recoil effect (Restricted arc if above 1.00): 0.08
Seaboat quality (Average = 1.00): 1.75

Hull form characteristics:
Hull has rise forward of midbreak
and transom stern
Block coefficient: 0.546
Length to Beam Ratio: 5.85 : 1
'Natural speed' for length: 23.59 kts
Power going to wave formation at top speed: 49 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 18.00 degrees
Stern overhang: 9.84 ft / 3.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 21.88 ft / 6.67 m
- Forecastle (20 %): 21.88 ft / 6.67 m
- Mid (50 %): 21.88 ft / 6.67 m (13.88 ft / 4.23 m aft of break)
- Quarterdeck (15 %): 13.88 ft / 4.23 m
- Stern: 13.88 ft / 4.23 m
- Average freeboard: 17.88 ft / 5.45 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 63.3 %
- Above water (accommodation/working, high = better): 153.5 %
Waterplane Area: 16,828 Square feet or 1,563 Square metres
Displacement factor (Displacement / loading): 188 %
Structure weight / hull surface area: 80 lbs/sq ft or 391 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.94
- Longitudinal: 1.88
- Overall: 1.01
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

The DeGroot class Seaplane carriers have :

200 tons true misc.
2x20 ton lighter/net tender
210 tons harbor-level torpedo netting
250 ton 20mx2.44x10m magazine with 50mm armor (used 50mm 10mx2.44m panel for base weight, 25 tons/panel x 10 panels)
250 tons extra berthing.
250 tons of general purpose maintenance forges.
and 1,300 tons dedicated to seaplanes and seaplane support.
SQRT(1300) = 36, (LxB)=31
Normal air suite is 24 seaplanes
-----
2,500 tons

Military aircraft database

For all your scale problems.

Why use the 57mm gun? Frankly, its crap. It fires a shell too small to do much damage against surface targets. It will destroy an aircraft with a direct hit however, but the shell is too large forw rapid loading. 20-30rpm is all that could be expected.

There are plenty of Italian, Iberian and Danish weapons available that fit what is needed.

Type: T.IVA
Function: torpedo-bomber / reconaissance
Year: Crew: 4 Engines: 2 * 559kW Wright Cyclone SR-1820-F2
Wing Span: 26.20m Length: 17.60m Height: 6.00m Wing Area: 97.80m2
Empty Weight: 4665kg Max.Weight: 7200kg
Speed: 260km/h Ceiling: 5900m Range: 1560km
Armament: 3*mg7.9mm 800kg


Thanks. She is a big bird. I will need more freeboard for hanger room with a height of 6m.

The 57mm- I know it's not particularly practical as a AA weapon, the 1928 40mm is what I "should" be mounting. It's far better in many ways.

However in projecting the threats the seaplane carrier would likely face while anchored on it's own somewhere, the aerial threat was presumed to be things like opposing versions of the T.IV - big, slow, and a little hard to kill. So the 57mm gives greater punch further out and a better chance of critical damage per shell. What's missing is that the 40mm is going to be about as good per shell with a better ROF, while the range advantage won't be huge.

Ok,
on the one hand she has the 8m freeboard to handle the T.IV in an enclosed hanger. On the other... why would a Seaplane carrier need an enclosed hanger as part of the structure? Regular carriers aren't necessarily done that way..... I did it here since the pic of Guiseppe seemed to have it, but I'm not sold on the need. I think the last DeGroot posted works fine for the role.

I also think I need to look for smaller seaplanes on that website when I have more time. My Jane's All the World's aircraft is sparse on Fokkers, and the Dorniers the Dutch next used aren't out yet.

She also sports the quad 40mms as the Italian Naval Attache's disparaging remarks were heard.

DeGroot 4, Netherlands Seaplane Carrier laid down 1930

Displacement:
5,360 t light; 5,542 t standard; 7,204 t normal; 8,533 t full load

Dimensions: Length overall / water x beam x draught
412.07 ft / 393.70 ft x 59.06 ft (Bulges 67.26 ft) x 15.58 ft (normal load)
125.60 m / 120.00 m x 18.00 m (Bulges 20.50 m) x 4.75 m

Armament:
4 - 4.92" / 125 mm guns in single mounts, 59.59lbs / 27.03kg shells, 1930 Model
Dual purpose guns in deck mounts with hoists
on side ends, evenly spread
32 - 1.57" / 40.0 mm guns (8x4 guns), 1.95lbs / 0.89kg shells, 1930 Model
Anti-aircraft guns in deck mounts
on side, evenly spread
4 - 0.52" / 13.2 mm guns in single mounts, 0.07lbs / 0.03kg shells, 1930 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 301 lbs / 137 kg
Shells per gun, main battery: 200

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Ends: 1.57" / 40 mm 32.81 ft / 10.00 m 8.01 ft / 2.44 m
360.89 ft / 110.00 m Unarmoured ends

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.59" / 15 mm 0.31" / 8 mm 0.39" / 10 mm
2nd: 0.59" / 15 mm - -
3rd: 0.59" / 15 mm - -

- Conning tower: 0.79" / 20 mm

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 8,211 shp / 6,125 Kw = 18.00 kts
Range 16,650nm at 15.00 kts
Bunker at max displacement = 2,991 tons

Complement:
390 - 508

Cost:
£1.062 million / $4.250 million

Distribution of weights at normal displacement:
Armament: 38 tons, 0.5 %
Armour: 32 tons, 0.4 %
- Belts: 15 tons, 0.2 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 10 tons, 0.1 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 6 tons, 0.1 %
Machinery: 249 tons, 3.5 %
Hull, fittings & equipment: 2,542 tons, 35.3 %
Fuel, ammunition & stores: 1,843 tons, 25.6 %
Miscellaneous weights: 2,500 tons, 34.7 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
20,269 lbs / 9,194 Kg = 340.1 x 4.9 " / 125 mm shells or 3.3 torpedoes
Stability (Unstable if below 1.00): 1.13
Metacentric height 2.9 ft / 0.9 m
Roll period: 16.7 seconds
Steadiness - As gun platform (Average = 50 %): 76 %
- Recoil effect (Restricted arc if above 1.00): 0.08
Seaboat quality (Average = 1.00): 2.00

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.611
Length to Beam Ratio: 5.85 : 1
'Natural speed' for length: 23.40 kts
Power going to wave formation at top speed: 45 %
Trim (Max stability = 0, Max steadiness = 100): 38
Bow angle (Positive = bow angles forward): 18.00 degrees
Stern overhang: 9.84 ft / 3.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 26.25 ft / 8.00 m
- Forecastle (20 %): 26.25 ft / 8.00 m
- Mid (50 %): 26.25 ft / 8.00 m
- Quarterdeck (15 %): 26.25 ft / 8.00 m
- Stern: 26.25 ft / 8.00 m
- Average freeboard: 26.25 ft / 8.00 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 54.2 %
- Above water (accommodation/working, high = better): 229.6 %
Waterplane Area: 17,910 Square feet or 1,664 Square metres
Displacement factor (Displacement / loading): 216 %
Structure weight / hull surface area: 79 lbs/sq ft or 386 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.85
- Longitudinal: 4.89
- Overall: 1.01
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

The DeGroot class Seaplane carriers have :

200 tons true misc.
2x20 ton lighter/net tender
210 tons harbor-level torpedo netting
250 ton 20mx2.44x10m magazine with 50mm armor (used 50mm 10mx2.44m panel for base weight, 25 tons/panel x 10 panels)
250 tons extra berthing.
250 tons of general purpose maintenance forges.
and 1,300 tons dedicated to seaplanes and seaplane support.
SQRT(1300) = 36, (LxB)=31
Normal air suite is 24 seaplanes
-----
2,500 tons

What are the specs of the Akitsushima?

Uh oh! Looks like someone has his eyes on a ship he wants to build! :-)

http://warships.web4u.cz/lode.php?langua…ida=Akitsushima