WesWorld

Big Rich has been talking about the virtues of seaplanes in a thread about my little MTB tenders over at the Warship Projects Board. His point is that seaplanes could be used to scout out MTB targets or help my ASW launches chase submarines, and advocated considering a larger tender that could carry a few planes.

As an alternative, I'm thinking about some small, cheap, fast-ish patrol vessels with a limited aviation capability. These could indeed partner operationally with the MTBs or launches, using their two aircraft to look for targets or just keep an eye on things in a more generic patrol role. The limited armament is essentially defensive, but sufficient to deal with unruly civilian vessels or your more run-of-the-mill pirate.

Thoughts? It's a modification of the coastal minelayer in service already...



p, laid down 1929

Length, 86.0 m x Beam, 7.2 m x Depth, 2.7 m
725 tonnes normal displacement (625 tonnes standard)

Main battery: 1 x 10.5-cm
Secondary battery: 1 x 3.5-cm
AA battery: 4 x 1.5-cm

Weight of broadside: 17 kg

Hull unarmored

Battery armor:
Main, 3.0 cm shields / secondary, 2.0 cm shields
AA, 2.0 cm shields

Maximum speed for 10002 shaft kw = 28.44 knots
Approximate cruising radius, 6000 nm / 12 knots

Typical complement: 70-91


Estimated cost, $1.142 million (£286,000)

Remarks:

Caution: Hull structure is subject to strain in open-sea
conditions.

Ship has slow, easy roll; a good, steady gun platform.

Good seaboat; rides out heavy weather easily.

Magazines and engineering spaces are cramped, with poor
watertight subdivision.

Roomy upper decks; superior accommodation and working space.


Distribution of weights:
Percent
normal
displacement:

Armament ......................... 5 tonnes = 1 pct
Armor, total ..................... 2 tonnes = 0 pct

Armament 2 tonnes = 0 pct

Machinery ........................ 330 tonnes = 46 pct
Hull and fittings; equipment ..... 196 tonnes = 27 pct
Fuel, ammunition, stores ......... 117 tonnes = 16 pct
Miscellaneous weights ............ 75 tonnes = 10 pct
-----
725 tonnes = 100 pct

Estimated metacentric height, 0.3 m

Displacement summary:

Light ship: 608 tonnes
Standard displacement: 625 tonnes
Normal service: 725 tonnes
Full load: 802 tonnes

Loading submergence 355 tonnes/metre

+++++++++++++++++++++++++


Estimated overall survivability and seakeeping ability:

Relative margin of stability: 1.23

Shellfire needed to sink: 112 kg = 7.0 x 10.5-cm shells
(Approximates weight of penetrating
shell hits needed to sink ship,
not counting critical hits)

Torpedoes needed to sink: 0.2
(Approximates number of 'typical'
torpedo hits needed to sink ship)

Relative steadiness as gun platform, 70 percent
(50 percent is 'average')

Relative rocking effect from firing to beam, 0.11

Relative quality as a seaboat: 1.41

+++++++++++++++++++++++++


Hull form characteristics:

Block coefficient: 0.43
Sharpness coefficient: 0.29
Hull speed coefficient 'M' = 9.60
'Natural speed' for length = 16.8 knots
Power going to wave formation
at top speed: 62 percent


Estimated hull characteristics and strength:

Relative underwater volume absorbed by
magazines and engineering spaces: 163 percent

Relative accommodation and working space: 122 percent


Displacement factor: 77 percent
(Displacement relative to loading factors)


Relative cross-sectional hull strength: 0.55
(Structure weight per square
metre of hull surface: 122 kg)

Relative longitudinal hull strength: 1.20
(for 3.60 m average freeboard;
freeboard adjustment +0.87 m)

Relative composite hull strength: 0.59

+++++++++++++++++++++++++


[Machine-readable parameters: Spring Style v. 1.2.1]

282.08 x 23.62 x 8.86; 11.81 -- Dimensions
0.43 -- Block coefficient
1929 -- Year laid down
28.44 / 6000 / 12.00; Oil-fired turbine or equivalent -- Speed / radius / cruise
75 tons -- Miscellaneous weights
++++++++++
1 x 4.13; 0 -- Main battery; turrets
Central positioning of guns
Gun-shields
:
1 x 1.38; 0 -- Secondary battery; turrets
Gun-shields
:
4 x 0.59 -- Tertiary (QF/AA) battery
Gun-shields
:
0 -- No fourth (light) battery
0 -- No torpedo armament
++++++++++
0.00 -- No belt armor
0.00 / 0.00 -- Deck / CT
1.18 / 0.79 / 0.79 / 0.00 -- Battery armor


(Note: For portability, values are stored in Anglo-American units)


+++++++++++++++++++++++++++++++++++++++++++++++++++++++

I think topweight would kill it. That large hangar on such a small hull with the 2 aircraft in it would cause awful stability problems.

I was thinking the same thing, 725 tons is an awefully small hull. The U.S. planned to convert 6 Fletcher class DD's to carry a cat and floatplane, they only followed through with 3 conversions and they were later converted back to regular DD's which seems to indicate how far than idea went.

She does look rather nice though.......

I like the look of it and the idea......might be something for the Iberian Armada after the airships become less useful (more vulnerable!)

but as the others have said, it's top weight will kill it!
(If it was a model, you'd have to add a false keel to it!!)

It´s not her displacement but l:b ratio that kills her regarding top weight.

Just my thoughts...

So how does one include superstructure, flight decks, cranes, and hangers in SS? The added weight might do it, but won't direct the weight to were it will be. I've wondered this because in building carriers one has a lot of stuff above the freeboard deck (hanger deck in American ships), just like this Indian vessel. Is the freeboard the lowest deck, or just the lowest deck at that location, which might place the top of the hanger as freeboard for SS even though freeboard is suppose to be the lowest continuous deck that the sea can come in on a vessel.


(An attempt to recreate the Indian vessel, followed by a more radical freeboard change.)

Displacement:
609 t light; 627 t standard; 725 t normal; 801 t full load

Dimensions: Length overall / water x beam x draught
282.15 ft / 282.15 ft x 23.62 ft x 8.86 ft (normal load)
86.00 m / 86.00 m x 7.20 m x 2.70 m

Armament:
1 - 4.13" / 105 mm guns in single mounts, 35.32lbs / 16.02kg shells, 1929 Model
Quick firing gun in deck mount
on centreline forward
1 - 1.38" / 35.0 mm guns in single mounts, 1.31lbs / 0.59kg shells, 1929 Model
Dual purpose gun in deck mount
on centreline aft
4 - 0.59" / 15.0 mm guns (1x4 guns), 0.10lbs / 0.05kg shells, 1929 Model
Breech loading guns in deck mount
on centreline amidships
Weight of broadside 37 lbs / 17 kg
Shells per gun, main battery: 150

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

Machinery:
Oil fired boilers, steam turbines,
Direct drive, 2 shafts, 13,405 shp / 10,000 Kw = 28.44 kts
Range 6,000nm at 12.00 kts (Bunkerage = 176 tons)

Complement:
69 - 90

Cost:
£0.286 million / $1.143 million

Distribution of weights at normal displacement:
Armament: 5 tons, 0.6 %
Armour: 4 tons, 0.5 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 4 tons, 0.5 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 330 tons, 45.5 %
Hull, fittings & equipment: 196 tons, 27.0 %
Fuel, ammunition & stores: 116 tons, 16.0 %
Miscellaneous weights: 75 tons, 10.3 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
224 lbs / 102 Kg = 6.4 x 4.1 " / 105 mm shells or 0.2 torpedoes
Stability (Unstable if below 1.00): 1.23
Metacentric height 0.8 ft / 0.3 m
Steadiness - As gun platform (Average = 50 %): 80 %
- Recoil effect (Restricted arc if above 1.00): 0.12
Seaboat quality (Average = 1.00): 1.60

Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0.430
Length to Beam Ratio: 11.94 : 1
'Natural speed' for length: 16.80 kts
Power going to wave formation at top speed: 62 %
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: 19.69 ft / 6.00 m
- Forecastle (20 %): 16.40 ft / 5.00 m
- Mid (50 %): 16.40 ft / 5.00 m (8.20 ft / 2.50 m aft of break)
- Quarterdeck (15 %): 8.20 ft / 2.50 m
- Stern: 8.20 ft / 2.50 m
- Average freeboard: 12.57 ft / 3.83 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 163.2 %
- Above water (accommodation/working, high = better): 131.5 %
Waterplane Area: 3,974 Square feet or 369 Square metres
Displacement factor (Displacement / loading): 77 %
Structure weight / hull surface area: 20 lbs/sq ft or 96 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.44
- Longitudinal: 2.38
- Overall: 0.52
Hull space for machinery, storage, compartmentation is cramped
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

(And then as it looks in the drawing with the danger top as freeboard)

DESIGN FAILURE: Overall load weight too much for hull

Displacement:
609 t light; 627 t standard; 725 t normal; 801 t full load

Dimensions: Length overall / water x beam x draught
282.15 ft / 282.15 ft x 23.62 ft x 8.86 ft (normal load)
86.00 m / 86.00 m x 7.20 m x 2.70 m

Armament:
1 - 4.13" / 105 mm guns in single mounts, 35.32lbs / 16.02kg shells, 1929 Model
Quick firing gun in deck mount
on centreline forward
1 - 1.38" / 35.0 mm guns in single mounts, 1.31lbs / 0.59kg shells, 1929 Model
Dual purpose gun in deck mount
on centreline aft
4 - 0.59" / 15.0 mm guns (1x4 guns), 0.10lbs / 0.05kg shells, 1929 Model
Breech loading guns in deck mount
on centreline amidships
Weight of broadside 37 lbs / 17 kg
Shells per gun, main battery: 150

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

Machinery:
Oil fired boilers, steam turbines,
Direct drive, 2 shafts, 13,405 shp / 10,000 Kw = 28.44 kts
Range 6,000nm at 12.00 kts (Bunkerage = 176 tons)

Complement:
69 - 90

Cost:
£0.286 million / $1.143 million

Distribution of weights at normal displacement:
Armament: 5 tons, 0.6 %
Armour: 4 tons, 0.5 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 4 tons, 0.5 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 330 tons, 45.5 %
Hull, fittings & equipment: 196 tons, 27.0 %
Fuel, ammunition & stores: 116 tons, 16.0 %
Miscellaneous weights: 75 tons, 10.3 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
202 lbs / 92 Kg = 5.7 x 4.1 " / 105 mm shells or 0.2 torpedoes
Stability (Unstable if below 1.00): 1.09
Metacentric height 0.7 ft / 0.2 m
Steadiness - As gun platform (Average = 50 %): 100 %
- Recoil effect (Restricted arc if above 1.00): 0.28
Seaboat quality (Average = 1.00): 2.00

Hull form characteristics:
Hull has rise aft of midbreak, low quarterdeck
Block coefficient: 0.430
Length to Beam Ratio: 11.94 : 1
'Natural speed' for length: 16.80 kts
Power going to wave formation at top speed: 62 %
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: 19.69 ft / 6.00 m
- Forecastle (20 %): 16.40 ft / 5.00 m
- Mid (50 %): 16.40 ft / 5.00 m (22.97 ft / 7.00 m aft of break)
- Quarterdeck (15 %): 8.20 ft / 2.50 m (22.97 ft / 7.00 m before break)
- Stern: 8.20 ft / 2.50 m
- Average freeboard: 17.73 ft / 5.41 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 163.2 %
- Above water (accommodation/working, high = better): 218.7 %
Waterplane Area: 3,974 Square feet or 369 Square metres
Displacement factor (Displacement / loading): 77 %
Structure weight / hull surface area: 13 lbs/sq ft or 64 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.25
- Longitudinal: 6.78
- Overall: 0.34
Hull space for machinery, storage, compartmentation is cramped
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

Consensus seems to be that this is a flawed design. What are folks' thoughts on the concept in general, though?

I like the concept, but it seems the vessel will need to be bigger in some way to handle the hanger and aircraft.

Rocky,

What you've got here is much more a scout for you light forces (I like the term "pathfinder" you used) that don't happen to be operating with indigenous air scouting assets.

See my response to your post over on the projects board.

Wes,

I wouldn't judge the concept by what the USN did with the scout Fletchers. The USN had obscene amounts of resources, and like the Marines concept of using float fighter and float dive bombers from anchorages, the reality of the war was more planes were available than planning had indicated.

Just as the RN pulled aircraft off their capital ships because they were always going to be in company with a carrier, the USN pulling the Scout Fletchers doesn't mean the concept is flawed. WesWorld hasn't yet seen the total ascendency of the carrier yet or the rise of the escort carrier. Large navies like Atlantean, the RN or the USN probably wouldn't have much use for such a vessel. Even the Omaha's carried scout planes. But a smaller navy that might conduct sweeps of TB and DD might find a role for such a ship.

Regards,

Big Rich

Good points, and I do like the basic idea, just look at my scout blimp tenders. The two converted DD's will pave the way for a few more ships like them to support the growing number of scouting blimps.

I like it as a concept, and might pinch the idea for the Armada, but it just needs to be a bit bigger!!

Commodore - if you like the idea, you can officially "pinch" the idea when I lay down an experimental unit in 1929. The dimensions may be larger, and I'm thinking a collapsable canvas hanger rather than a steel hanger at this point.

Always happy to help my rivals...

I think its a good idea. The ship is very similar to one of my Multi Purpose Ships.

Does it really need a hangar and a cat? I think it could do without them. Or with a canvas hangar.

I think the cat is necessary. Forcing the ship to stop when it wants to launch the plane seems inconvenient, and maybe dangerous, if the idea is to have the ship break contact with an enemy formation while the plane does the shadow work.

I don't think the permanent hanger is necessary, though, and am looking at a canvas hanger as you suggest. Since it's a lightweight metal frame with the heavy fabric, I can't see it being much trouble from a topweight perspective.

The prototype will be larger, in the thousand tonne range. I can see it spawning more dedicated sloop or destroyer escort models but not mine-warfare vessels. The question will be whether I leave the speed low enough for it to be considered a coastal defence ship, or hike it up enough that I use destroyer tonnage for it (not that this worries me - my allocation seems adequate for the tasks at hand).