WesWorld

1941 Naval Planning Committee

Construction is now underway on the five Admiral Class battleships. During the Committee meeting the final plans were signed off. Changes in the design include a revised secondary outfit with different mounts requiring minor changes to the magazines and a few major changes to the hoists and the surrounding structure. A decision has been made to locate all but one of the emergency generators inside the armoured citadel with only a diesel generator forward being outside the main armoured area. In the light of several trials recently it has been decided to add three bilge pumps aft to increase pumping capacity and the rudder machinery rooms now have a full back-up hydraulic system independent of the main system with a small dynamo as well inside the compartment. The DEE (Director of Electrical Engineering) outlined the likely types of radar to be developed by 1945 and generally it was agreed that the ship had enough space for the electronics but estimates regarding weight have grown since the initial studies. After much debate it was decided to reveal publically in 1941 the true statistics and specification of the Admiral Class, partly due to political pressure to do so.
The Queen Elizabeth Class refit programme is now close to finishing with work on the fifth ship (HMS Malaya) which should complete in mid-1941. HMS Inflexible has been refitted during 1940 with HMS Invincible to follow in 1941.

Commander in Chief Fleet Air Aim Admiral R. G. H. Henderson’s two new fleet carriers (Carrier M & N) have been approved and laid down as HMS Audacious and HMS Formidable with carriers O & P (HMS Leviathan and HMS Magnificent) to follow when the first two hulls are launched. The fleet will have ten fleet carriers when these ships complete and several on the panel felt that the Navy would have too many carriers by 1946. It was decided at the meeting that the DNC should begin preparing refit plans for the Ark Royal and Majestic and their half-sisters the Swiftsure, Bulwark and Warrior. Schedules have yet to be drafted but it is assumed all will begin refitting from 1942 at the rate of one per year. As aircraft weights and sizes increase so the equipment to handle them must be improved. It is thought radio-location will be added along with new arrestor gear, modified lift motors and new hydraulic catapults. The 4.7in guns currently carried may be replaced by 4.5in mounts.
Two further Ocean Class carriers (K & L) are still on hold, it is likely both will be ordered in 1945 as a new light carrier class to replace the existing Ocean Class.

The cruiser programme remains paused and the Committee reviewed last year’s cruiser studies and the few made since that time and it has been decided to wait until the new automatic 6in mount is ready.

Due to the availability of funds and slip space work has already begun on the AA cruiser programme as the five ships of the Minotaur Class. The Commander in Chief Fleet Air Aim, Admiral R. G. H. Henderson, said that the four new Audacious class carriers would require additional AA defence and pressed for another five ships. The first five ships will replace the four converted Ceres Class cruisers rebuilt into interim AA cruisers. Thus the fleet will still be short of the type of vessel and all the C conversions are running out of hull life and will need replacing before the end of the forties. The DNO doubted whether the automatic 6in gun would ever be suitable for AA defence, even at longer-ranges. It was decided that if the automatic 6in gun isn’t ready by 1944 that another five Minotaurs should be built during 1942-43.

The heavy cruiser programme continues with two Iron Duke Class cruisers now nearing completion. No further heavy cruiser studies have been made and such a type now seems unlikely to be built for at least another year. The DNC is going to look at modernised Howe-type designs during 1941.

The M Class destroyers for 1941 are repeats of the L Class with identical armament. The only changes are the addition of the new Type 275 Destroyer Search Set, upgraded Type 286 and the addition of Type 282 for directing the 57mm Mk II guns. Also added for fleet scouting work is radio and radio-location passive detection systems. The N Class planned for next year will be identical to the M’s in all respects. With little room for growth left this will be the last class of this basic design going back to the F Class. The DNC has already begun studies for a new fleet destroyer armed with the new 4.5in mounts now under development for the Admiral and Audacious Classes incorporating new boilers and turbines and being of much larger size.

The Admiralty has recently decided to renew the policy of the late 19th and early 20th centuries of building ‘Specials’ ships that incorporate new ideas and concepts in full size for extensive testing. One of the first of these has been intensively studied during 1940 by the DNC and he made a special presentation of the type to the Planning Committee. It is to be a showcase design.
It is of the destroyer class but somewhat larger than current destroyers being over 450 feet in length and displacing around 4,000 tons. The DNC has designed a sleek hull with box protection for the magazines. The DNO has provided a main armament of “novel type and layout” and it is understood that a research contract has already been issued to a Canadian firm to begin development. The AA armament comprises eight of the new 2pdr guns and eight torpedo tubes, all fixed and angled outboard on the upper deck, although the DNC prefers to mount them inside the hull on the main deck. The E-in-C (Engineer-in-Chief) and the DME (Director of Mechanical Engineering) outlined the novel steam boilers to be used alongside an electric drive as used on some American vessels to provide for a quieter ship and greater responsiveness. It is hoped that it will save internal space aft as well. The DASW (Director of Anti-Submarine Warfare) outlined the initial work on-going to develop a depth-charge mortar-launcher and the DNC has made space for tw0 of these devices aft with no provision for depth-charges at all. Up to three ASDIC sets, all of prototype nature, will be fitted. The DEE (Director of Electrical Engineering) offered his thoughts on the possibility of carrying X-band radars for search and several “blind-firing” directors for AA use with height-finding radar. The DRW (Director of Radio Warfare) then gave a report on the likely passive detection systems to be employed and he hoped to fit the first series of lightweight radio-beam jamming devices to the ship and his work was being assisted by Dr R.V. Jones. In all the various equipment should be ready by 1945 and so it has been decided to order the ship for the 1944 programme and the basic design continues on-going development with at least ten sketch designs proposed already. If successful the First Sea Lord felt it would, “revolutionise destroyer warfare.”

The DNO drafted a new 2pdr specification during 1940 due to misgivings over the 0.661in HMG lacking heavier stopping power and has now been issued and development has begun at Vickers on a new design with a 70-calibre barrel and a new 2pdr shell with improved shellform. The DNO hopes firing trials will begin in 1942 and the DGD welcomed the new gun for smaller vessels. It is planned to mount it in both single and twin mounts.

The 500 ton colonial gunboat programme is on-going with the 16 vessels now being commissioned, built, or planned. No further colonial vessels are planned, the Committee now focusing solely on fleet units.

Much attention was paid to the large MTB-type vessel ordered by Chile built and partly designed by William Denny & Brothers. The vessel was deemed suitable for future roles in the RN Coastal Forces, especially in the Far East. Although the DNC had inspected the plans he felt the design fell short of our construction requirements but with further design he felt it could be a serviceable design. No decision was reached on whether to order an experimental design from Denny but funds might be laid aside at the end of the year to begin design work on such a vessel.

That really is a lot of aircraft carriers, especially large fleet types. I'd think the double hangars on Ark Royal and Swiftsure classes would limit capacity to absorb future aircraft types. Depends whether you get into types like the Wyvern, Sturgeon, Spearfish or Sea Hornet. With Audacious-Class large fleet carriers around I can't see the older smaller types lasting that long.

Minotaur-Class cruisers are a mix match between Dido/Fiji with 12x4.5"?

Daring Type destroyers as the next class I'd guess? I would have thought that a destroyer along the lines of the Gallant-Class would be a more suitable follow on given the presence of Cathedral-Class large destroyers/cruisers.

The special type destroyer will be interesting to compare with the Italian large destroyers. Personally, I'd don't think the "special" type will work as well as at the turn of the century. Added complications, moving towards weapons systems concepts, and simple cost and complexity would make one or two-offs ruinously expensive. New types of hull, machinery, electronics, guns, a/s weapons arrrggghhh it's suddenly a nightmare. I can see the response from the treasury as being "this destroyer has cost half as much as a battleship, we're definitely not building any more". It's getting to the stage where the cost of developing the systems is costing more than the ship itself. It all adds up to horrendous expense.

Novel type and layout of the armament means fully automatic 5.5" guns, maybe arranged on the lines of the 1950s Cruiser-Destroyer design (which is where I drew my inspiration from as well). I'm not sure on the fixed torpedo tubes. With conventional torpedoes they make sense for saving space, and yet I'm sure they'll be firing guided torpedoes. I'd really question the Squid a/s setup given that there's no reason to doubt the effectiveness of depth charges. I'm really not sure on the turbo-electric drive either. Adds considerable weight and volume and doesn't quieten the ship much as you've still got the boiler noises and the props.

Carrier design has moved quite quickly, once upon a time the Ark Royal and Swiftsure looked pretty good and ok for years. But aircraft keep growing and the ships to carry, tend and use them get bigger too. The Audacious won't complete for another 3 years so there is scope to give them a minor refit each with some radar etc. Some could be rebuilt a la Victorious but that would be Expensive.

SS report for the Minotaur Class is now posted in the UK pages. Think more along the lines of the Canadian Labrador class etc.

Who mentioned Darings? We're a few years away from that yet.

RA, you've hit more nails on the head than not on the Special. Expensive yes but if she works, then I figure on using her as the prototype of a new class. Anyhow its better than rebuilding an existing ship as most rebuild and mods mean compromises and more complications than usually planned. This way we kill a dozen birds with one stone. I take your point on the TE powerplant.
At the ASW Research Establishment all kinds of Boffins are aboard destroyers as the Ping up and down Lochs, and aboard submarines trying to avoid the Pings and messing around with slide-rules and notepads. The concept of an ahead-throwing charge is something they have thought of, now they just need to see if it works and how.

With the carriers, it's almost better to just build more of the larger fleet types than rebuild the old ones. Worth updating them a bit to keep them current up to till 1955 or so, but likely too small after that. Running costs will also be an issue. I don't see 8 fleet carriers as sustainable.

The Minotaurs make an interesting comparison with the N2 design from 1944. Similar size but Springsharp allows for much more to be put onto the same hull. It's starting to get into more volume limited design instead of weight limited, which SS just doesn't do.

The issue I have with the Special destroyer is mostly risk. Putting lots of new stuff onto a single hull increases risk a lot, and cost even more so.

Ahead-Throwing depth charges have been around for quite a while (e.g. the five wide virgins) but really needed the lack of effectiveness of depth charges to be made known - and that was after the fall of France. Still, without forward firing anti-submarine weapons Italy was doing pretty well in the Med. I just don't see there being a particularly large driver for anti-submarine weapons like Squid or Limbo.

Six fleet carriers is the optimum for the fleet, maybe a seventh in rotating reserve. I can see two follow-on Audacious replacing the last of the Ark Royals and Swiftsures by 1955.

I agree on the AACL, space is an issue. I don't think its too serious but I do think its at the limit of the possible with 40s electronic technology. Certainly any future types will need to be much larger. As you say volume is now is becoming the vital factor in design just like OTL.

After much debate within the Admiralty, and under Parliamentry and press pressure, the details of the Admiral Class are made public.




Admiral Class, Great Britain Battleship laid down 1939

Displacement:
57,364 t light; 60,355 t standard; 62,712 t normal; 64,597 t full load

Dimensions: Length overall / water x beam x draught
881.00 ft / 875.00 ft x 123.00 ft x 33.00 ft (normal load)
268.53 m / 266.70 m x 37.49 m x 10.06 m

Armament:
12 - 16.50" / 419 mm guns (4x3 guns), 2,500.00lbs / 1,133.98kg shells, 1935 Model
Breech loading guns in turrets (on barbettes)
on centreline ends, evenly spread, 2 raised mounts - superfiring
20 - 4.50" / 114 mm guns (10x2 guns), 45.00lbs / 20.41kg shells, 1943 Model
Automatic rapid fire guns in deck mounts with hoists
on side, all amidships, 4 raised mounts - superfiring
16 - 2.24" / 57.0 mm guns (8x2 guns), 6.00lbs / 2.72kg shells, 1939 Model
Anti-aircraft guns in deck mounts
on side ends, evenly spread, all raised mounts - superfiring
36 - 0.66" / 16.8 mm guns (6x6 guns), 0.14lbs / 0.06kg shells, 1943 Model
Machine guns in deck mounts
on side ends, evenly spread, all raised mounts - superfiring
Weight of broadside 31,001 lbs / 14,062 kg
Shells per gun, main battery: 100

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 16.0" / 406 mm 540.00 ft / 164.59 m 16.50 ft / 5.03 m
Ends: Unarmoured
Main Belt covers 95 % of normal length

- Torpedo Bulkhead:
2.75" / 70 mm 540.00 ft / 164.59 m 30.00 ft / 9.14 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 16.0" / 406 mm 12.0" / 305 mm 12.0" / 305 mm
2nd: 2.00" / 51 mm 1.00" / 25 mm 3.00" / 76 mm
3rd: 0.50" / 13 mm - -
4th: 0.50" / 13 mm - -

- Armour deck: 6.50" / 165 mm, Conning tower: 3.00" / 76 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 170,000 shp / 126,820 Kw = 30.09 kts
Range 10,000nm at 12.00 kts
Bunker at max displacement = 4,243 tons

Complement:
1,980 - 2,575

Cost:
£32.620 million / $130.480 million

Distribution of weights at normal displacement:
Armament: 3,518 tons, 5.6 %
Armour: 23,020 tons, 36.7 %
- Belts: 6,240 tons, 10.0 %
- Torpedo bulkhead: 1,648 tons, 2.6 %
- Armament: 4,993 tons, 8.0 %
- Armour Deck: 10,036 tons, 16.0 %
- Conning Tower: 102 tons, 0.2 %
Machinery: 4,600 tons, 7.3 %
Hull, fittings & equipment: 25,927 tons, 41.3 %
Fuel, ammunition & stores: 5,347 tons, 8.5 %
Miscellaneous weights: 300 tons, 0.5 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
94,116 lbs / 42,690 Kg = 41.9 x 16.5 " / 419 mm shells or 15.4 torpedoes
Stability (Unstable if below 1.00): 1.10
Metacentric height 8.2 ft / 2.5 m
Roll period: 18.0 seconds
Steadiness - As gun platform (Average = 50 %): 59 %
- Recoil effect (Restricted arc if above 1.00): 0.71
Seaboat quality (Average = 1.00): 1.09

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.618
Length to Beam Ratio: 7.11 : 1
'Natural speed' for length: 34.26 kts
Power going to wave formation at top speed: 51 %
Trim (Max stability = 0, Max steadiness = 100): 54
Bow angle (Positive = bow angles forward): 10.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 34.00 ft / 10.36 m
- Forecastle (18 %): 29.00 ft / 8.84 m
- Mid (70 %): 21.00 ft / 6.40 m
- Quarterdeck (18 %): 21.00 ft / 6.40 m
- Stern: 21.00 ft / 6.40 m
- Average freeboard: 24.88 ft / 7.58 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 80.2 %
- Above water (accommodation/working, high = better): 194.7 %
Waterplane Area: 83,458 Square feet or 7,753 Square metres
Displacement factor (Displacement / loading): 103 %
Structure weight / hull surface area: 239 lbs/sq ft or 1,169 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.98
- Longitudinal: 1.20
- Overall: 1.00
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is excellent

Class Names: HMS Nelson, Rodney, Howe, Anson, Beatty

Radar Equipment List
Gunnery Director Radar Type 284M on three main directors
Gunnery Director Radar Type 289 on all six 57mm directors
Gunnery Director Radar Type 288 on four 4.5in directors
Air Search Radar Type 971
Surface Search Radar Type 278
Passive Radio Intercept Equipment Type 293, 293P/M/Q/O
Passive Radar Intercept Type 297
Missile Guidance Jammer Type 296

Armour Notes
Deck armour: 6 inch thick main deck with a 0.5in splinter protection deck above the engine rooms and magazines at lower deck level which joins onto bottom of belt and TB system
Torpedo bulkheads: triple bottom, quadruple side bulkhead system air/ fuel/ fuel/ air with backing bulkheads of 0.5in/ 1in/ 1in and 0.25in respectively

"Missile Guidence Jammer" Do we even have guided missiles yet?....ignoring those Mexican fantasies, the Larynx, etc.

Damn! Indian secrets are being made public! Heads will roll for this lack of security.

The electronic fit is a 1945 fit when the ships complete. As yet weight is devoted to "unknown electronic devices" and radars as being defined in labs now.

I thought they looked a bit naked with just 3 turrets.

The AAA fit seems comparatively light; a few semi-automatic 57mm and heavy machine guns. I'd think a few octuple 2pdrs would be better.

On the radar issue, there's obviously quite a lot of them. Some of the secondary directors seem to be radar only (with the little parabolic dishes) with no optical back up. That seems a bit risky. I love that there's still a good outfit of searchlights as well...

It's an interesting comparison to some of the later Lion designs with the benefit of war experience.

New ships for 1941;

Dale Class: 17,000 tons; 483x59x27.5ft; 3,500bhp Burmeister & Wain diesels 11.5kts; deadweight capacity 12,000 tons.
Ships to be built during 1941; Cedardale, Dewdale, Eaglesdale and Easedale.

Brigand, Marauder, Briton and Buccaneer; Salvage Tugs; 840 tons; 174x32x10.5ft; 3,000hp triple expansion, two shafts 15.5kts; 390 tons oil fuel; 1x 3in AA and two LMG; complement 43; has towing winches to tow targets and salvage equipment.


Hecla, Artifex, Clyde, Scapa, Great Britain Destroyer/ Submarine Tender laid down 1941

Displacement:
11,053 t light; 11,346 t standard; 12,560 t normal; 13,531 t full load

Dimensions: Length overall / water x beam x draught
574.58 ft / 570.00 ft x 85.50 ft x 20.00 ft (normal load)
175.13 m / 173.74 m x 26.06 m x 6.10 m

Armament:
4 - 4.50" / 114 mm guns (2x2 guns), 45.00lbs / 20.41kg shells, 1935 Model
Dual purpose guns in deck mounts with hoists
on centreline ends, evenly spread
8 - 1.57" / 40.0 mm guns (4x2 guns), 2.00lbs / 0.91kg shells, 1941 Model
Anti-aircraft guns in deck mounts
on side, all amidships, all raised mounts - superfiring
24 - 0.66" / 16.8 mm guns (4x6 guns), 0.14lbs / 0.06kg shells, 1938 Model
Machine guns in deck mounts
on side ends, evenly spread, all raised mounts - superfiring
Weight of broadside 199 lbs / 90 kg
Shells per gun, main battery: 350

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.50" / 38 mm 1.00" / 25 mm 1.00" / 25 mm
2nd: 0.50" / 13 mm 0.50" / 13 mm -
3rd: 0.50" / 13 mm - -

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 20,000 shp / 14,920 Kw = 21.01 kts
Range 15,000nm at 12.00 kts
Bunker at max displacement = 2,184 tons

Complement:
593 - 771

Cost:
£2.980 million / $11.919 million

Distribution of weights at normal displacement:
Armament: 25 tons, 0.2 %
Armour: 19 tons, 0.1 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 19 tons, 0.1 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 529 tons, 4.2 %
Hull, fittings & equipment: 4,381 tons, 34.9 %
Fuel, ammunition & stores: 1,506 tons, 12.0 %
Miscellaneous weights: 6,100 tons, 48.6 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
25,207 lbs / 11,434 Kg = 553.2 x 4.5 " / 114 mm shells or 3.4 torpedoes
Stability (Unstable if below 1.00): 1.11
Metacentric height 4.8 ft / 1.5 m
Roll period: 16.4 seconds
Steadiness - As gun platform (Average = 50 %): 71 %
- Recoil effect (Restricted arc if above 1.00): 0.02
Seaboat quality (Average = 1.00): 1.98

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.451
Length to Beam Ratio: 6.67 : 1
'Natural speed' for length: 23.87 kts
Power going to wave formation at top speed: 38 %
Trim (Max stability = 0, Max steadiness = 100): 36
Bow angle (Positive = bow angles forward): 10.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 26.00 ft / 7.92 m
- Forecastle (20 %): 23.00 ft / 7.01 m
- Mid (50 %): 23.00 ft / 7.01 m
- Quarterdeck (15 %): 23.00 ft / 7.01 m
- Stern: 23.00 ft / 7.01 m
- Average freeboard: 23.24 ft / 7.08 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 68.9 %
- Above water (accommodation/working, high = better): 229.8 %
Waterplane Area: 31,112 Square feet or 2,890 Square metres
Displacement factor (Displacement / loading): 170 %
Structure weight / hull surface area: 99 lbs/sq ft or 484 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.95
- Longitudinal: 1.70
- 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

Hecla and Artiflex are destroyer tenders equipped with stores, a bakery (2,500lbs of bread per day), two furnaces capable of melting 500lbs at tempratures up to 1,500 degrees, a foundry and machine shops with milling and grinding machines.

Clyde and Scapa are submarine tenders equipped with stores, kitchens, a foundry, coppersmiths shop, plumbers shop , carpenters shop, heavy and light machine shops and electrical and torpedo repair shops and plant for charging submarine batteries.

Hecla and Clyde will lay down next year.

Another new fleet auxiliary ship;

RFA Isle of Wight, Great Britain Transport laid down 1941

Displacement:
703 t light; 730 t standard; 1,090 t normal; 1,378 t full load

Dimensions: Length overall / water x beam x draught
251.57 ft / 250.00 ft x 26.00 ft x 12.00 ft (normal load)
76.68 m / 76.20 m x 7.92 m x 3.66 m

Armament:
1 - 4.00" / 102 mm guns in single mounts, 31.00lbs / 14.06kg shells, 1932 Model
Dual purpose gun in deck mount
on centreline aft
2 - 1.57" / 40.0 mm guns in single mounts, 2.00lbs / 0.91kg shells, 1922 Model
Anti-aircraft guns in deck mounts
on side, all amidships, all raised mounts - superfiring
Weight of broadside 35 lbs / 16 kg
Shells per gun, main battery: 250

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.00" / 25 mm - -

Machinery:
Diesel Internal combustion motors,
Geared drive, 1 shaft, 5,600 shp / 4,178 Kw = 21.01 kts
Range 9,500nm at 16.00 kts
Bunker at max displacement = 648 tons

Complement:
94 - 123

Cost:
£0.303 million / $1.214 million

Distribution of weights at normal displacement:
Armament: 4 tons, 0.4 %
Armour: 2 tons, 0.2 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 2 tons, 0.2 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 148 tons, 13.6 %
Hull, fittings & equipment: 368 tons, 33.8 %
Fuel, ammunition & stores: 387 tons, 35.5 %
Miscellaneous weights: 180 tons, 16.5 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1,900 lbs / 862 Kg = 59.4 x 4.0 " / 102 mm shells or 0.9 torpedoes
Stability (Unstable if below 1.00): 1.11
Metacentric height 0.8 ft / 0.2 m
Roll period: 12.1 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.07
Seaboat quality (Average = 1.00): 2.00

Hull form characteristics:
Hull has raised forecastle, rise aft of midbreak
Block coefficient: 0.489
Length to Beam Ratio: 9.62 : 1
'Natural speed' for length: 15.81 kts
Power going to wave formation at top speed: 56 %
Trim (Max stability = 0, Max steadiness = 100): 35
Bow angle (Positive = bow angles forward): 5.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 18.00 ft / 5.49 m
- Forecastle (16 %): 18.00 ft / 5.49 m (10.00 ft / 3.05 m aft of break)
- Mid (75 %): 10.00 ft / 3.05 m (18.00 ft / 5.49 m aft of break)
- Quarterdeck (15 %): 18.00 ft / 5.49 m
- Stern: 18.00 ft / 5.49 m
- Average freeboard: 13.28 ft / 4.05 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 66.4 %
- Above water (accommodation/working, high = better): 93.0 %
Waterplane Area: 4,114 Square feet or 382 Square metres
Displacement factor (Displacement / loading): 212 %
Structure weight / hull surface area: 37 lbs/sq ft or 178 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.84
- Longitudinal: 4.79
- Overall: 1.00
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

Misc Weight
120 tons cargo
20 tons crane and handling gear
20 tons extra crew accomodation
20 tons growth

HMS Adventure, Great Britain Cruiser Minelayer laid down 1941

Displacement:
10,764 t light; 11,090 t standard; 11,613 t normal; 12,032 t full load

Dimensions: Length overall / water x beam x draught
625.47 ft / 620.00 ft x 68.00 ft x 15.60 ft (normal load)
190.64 m / 188.98 m x 20.73 m x 4.75 m

Armament:
9 - 6.00" / 152 mm guns (3x3 guns), 108.00lbs / 48.99kg shells, 1941 Model
Breech loading guns in turrets (on barbettes)
on centreline ends, majority forward, 1 raised mount - superfiring
12 - 2.24" / 57.0 mm guns (6x2 guns), 6.00lbs / 2.72kg shells, 1941 Model
Anti-aircraft guns in deck mounts
on side, all amidships, all raised mounts - superfiring
12 - 1.57" / 40.0 mm guns (6x2 guns), 2.00lbs / 0.91kg shells, 1941 Model
Anti-aircraft guns in deck mounts
on side ends, evenly spread, all raised mounts - superfiring
Weight of broadside 1,068 lbs / 484 kg
Shells per gun, main battery: 150
8 - 21.0" / 533.4 mm above water torpedoes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 4.00" / 102 mm 418.00 ft / 127.41 m 10.00 ft / 3.05 m
Ends: 2.00" / 51 mm 121.00 ft / 36.88 m 9.00 ft / 2.74 m
81.00 ft / 24.69 m Unarmoured ends
Main Belt covers 104 % of normal length
Main belt does not fully cover magazines and engineering spaces

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 3.00" / 76 mm 2.00" / 51 mm 2.00" / 51 mm
2nd: 0.50" / 13 mm 0.50" / 13 mm -
3rd: 0.50" / 13 mm 0.50" / 13 mm -

- Armour deck: 2.00" / 51 mm, Conning tower: 2.00" / 51 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 128,000 shp / 95,488 Kw = 34.05 kts
Range 6,000nm at 12.00 kts
Bunker at max displacement = 942 tons

Complement:
559 - 727

Cost:
£5.947 million / $23.787 million

Distribution of weights at normal displacement:
Armament: 133 tons, 1.1 %
Armour: 2,154 tons, 18.5 %
- Belts: 782 tons, 6.7 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 190 tons, 1.6 %
- Armour Deck: 1,160 tons, 10.0 %
- Conning Tower: 22 tons, 0.2 %
Machinery: 3,383 tons, 29.1 %
Hull, fittings & equipment: 4,535 tons, 39.1 %
Fuel, ammunition & stores: 849 tons, 7.3 %
Miscellaneous weights: 560 tons, 4.8 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
13,819 lbs / 6,268 Kg = 128.0 x 6.0 " / 152 mm shells or 1.6 torpedoes
Stability (Unstable if below 1.00): 1.22
Metacentric height 4.1 ft / 1.2 m
Roll period: 14.2 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.17
Seaboat quality (Average = 1.00): 0.82

Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0.618
Length to Beam Ratio: 9.12 : 1
'Natural speed' for length: 24.90 kts
Power going to wave formation at top speed: 61 %
Trim (Max stability = 0, Max steadiness = 100): 61
Bow angle (Positive = bow angles forward): 10.00 degrees
Stern overhang: -3.00 ft / -0.91 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 31.00 ft / 9.45 m
- Forecastle (20 %): 26.00 ft / 7.92 m
- Mid (40 %): 25.50 ft / 7.77 m (17.00 ft / 5.18 m aft of break)
- Quarterdeck (20 %): 18.00 ft / 5.49 m
- Stern: 18.50 ft / 5.64 m
- Average freeboard: 21.40 ft / 6.52 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 108.9 %
- Above water (accommodation/working, high = better): 188.1 %
Waterplane Area: 31,357 Square feet or 2,913 Square metres
Displacement factor (Displacement / loading): 110 %
Structure weight / hull surface area: 101 lbs/sq ft or 494 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.99
- Longitudinal: 1.09
- Overall: 1.00
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent
Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

Misc Weight:
410 tons for 360 mines and equipment
100 tons for radars and electronic equipment
50 tons two aircraft and traverse catapult

Electronic Equipment
Radio Location Set Type 273 Aerial Search
Radio Location Set Type 274 High Definition Surface Search
Radio Location Director Type 285M two on main directors
Radio Location Director Type 282M three on secondary directors
HF/DF Type 292
Passive Radio Intercept Type 293 (P, Q, M and O)
Passive Radio Location Intercept Type 294 (294, M & 0)

My first reaction is that far too much is being asked of the design. Its protection is inadequate - failing to fully cover the magazines and engineering spaces; its seaworthyness in the open ocean is open to question. It seems far too much an investment.

It also seems out of place with my limited understanding of RN doctrine. Against whom is such a huge offensive minelayer intended to operate?

I'd have to concur with Bruce; There's no shortage of your old CLs you could convert to fast minelayers, while letting new tonnage remain free for more effective new cruisers.

You get inspiration from Roo on that? Seems too....quirky....

Why are there scuttles on the mine deck?

Why is C turret not raised one level to free the weatherdeck aft for higher mine capacity? I do not see that there is enought room below deck for so many mines... Because of rudder machinery, barbet and other stuff the mine deck will be very limited in size.

I do not understand why the RN accepts such a low seaboat rating.

The overall design reflects a normal fleet cruiser, which is okay, but for a minecruiser such heavy armament and size seems a waste. If on a mine raid, large size and profile are a risk, a gun fight has to be avoided anyway because any hit aft will blow up the ship anyway.

To sum it up, the whole thing does not make sense to me. Designing and drawing a standard cruiser and add mine doors aft does not work for me.

While I do like minelayers, I agree that this one seems a bit odd. I'm going to disagree with Bruce about the level of protection - with end-belts it's quite adequate and probably more historically correct. What I question is actually the size. For offensive minelaying, a smaller, more disposable ship with DP guns (such as the British design built for the Greeks) would be both more useful and less expensive. For defensive minelaying where the size is most useful, the speed is unnecessary.

The size is based on a real OTL design, only a rough design not a finished one, with the same dimensions as mine but with three twin 5.25in, 2x4 2pdr and 36 kts speed!

Anyhow what about this reduced version with 4.5in DP guns?


HMS Adventure, Great Britain Cruiser Minelayer laid down 1941

Displacement:
8,843 t light; 9,092 t standard; 9,584 t normal; 9,977 t full load

Dimensions: Length overall / water x beam x draught
625.47 ft / 620.00 ft x 68.00 ft x 15.60 ft (normal load)
190.64 m / 188.98 m x 20.73 m x 4.75 m

Armament:
6 - 4.50" / 114 mm guns (3x2 guns), 45.00lbs / 20.41kg shells, 1935 Model
Dual purpose guns in deck mounts with hoists
on centreline ends, majority forward, 2 raised mounts - superfiring
12 - 2.24" / 57.0 mm guns (6x2 guns), 6.00lbs / 2.72kg shells, 1941 Model
Anti-aircraft guns in deck mounts
on side, all amidships, all raised mounts - superfiring
12 - 1.57" / 40.0 mm guns (6x2 guns), 2.00lbs / 0.91kg shells, 1941 Model
Anti-aircraft guns in deck mounts
on side ends, evenly spread, all raised mounts - superfiring
Weight of broadside 366 lbs / 166 kg
Shells per gun, main battery: 250

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 4.00" / 102 mm 418.00 ft / 127.41 m 10.00 ft / 3.05 m
Ends: 2.00" / 51 mm 121.00 ft / 36.88 m 9.00 ft / 2.74 m
81.00 ft / 24.69 m Unarmoured ends
Main Belt covers 104 % of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.00" / 25 mm 0.50" / 13 mm 1.00" / 25 mm
2nd: 0.50" / 13 mm 0.50" / 13 mm -
3rd: 0.50" / 13 mm 0.50" / 13 mm -

- Armour deck: 2.00" / 51 mm, Conning tower: 2.00" / 51 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 95,000 shp / 70,870 Kw = 33.07 kts
Range 6,500nm at 12.00 kts
Bunker at max displacement = 885 tons

Complement:
483 - 629

Cost:
£4.323 million / $17.291 million

Distribution of weights at normal displacement:
Armament: 46 tons, 0.5 %
Armour: 1,873 tons, 19.5 %
- Belts: 778 tons, 8.1 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 26 tons, 0.3 %
- Armour Deck: 1,049 tons, 10.9 %
- Conning Tower: 19 tons, 0.2 %
Machinery: 2,511 tons, 26.2 %
Hull, fittings & equipment: 3,854 tons, 40.2 %
Fuel, ammunition & stores: 741 tons, 7.7 %
Miscellaneous weights: 560 tons, 5.8 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
15,733 lbs / 7,137 Kg = 345.3 x 4.5 " / 114 mm shells or 1.9 torpedoes
Stability (Unstable if below 1.00): 1.35
Metacentric height 4.7 ft / 1.4 m
Roll period: 13.1 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.05
Seaboat quality (Average = 1.00): 1.05

Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0.510
Length to Beam Ratio: 9.12 : 1
'Natural speed' for length: 24.90 kts
Power going to wave formation at top speed: 57 %
Trim (Max stability = 0, Max steadiness = 100): 48
Bow angle (Positive = bow angles forward): 10.00 degrees
Stern overhang: -3.00 ft / -0.91 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 31.00 ft / 9.45 m
- Forecastle (20 %): 26.00 ft / 7.92 m
- Mid (40 %): 25.50 ft / 7.77 m (17.00 ft / 5.18 m aft of break)
- Quarterdeck (20 %): 18.00 ft / 5.49 m
- Stern: 18.50 ft / 5.64 m
- Average freeboard: 21.40 ft / 6.52 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 95.8 %
- Above water (accommodation/working, high = better): 226.4 %
Waterplane Area: 28,348 Square feet or 2,634 Square metres
Displacement factor (Displacement / loading): 123 %
Structure weight / hull surface area: 93 lbs/sq ft or 454 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.98
- Longitudinal: 1.17
- Overall: 1.00
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent

Misc Weight:
410 tons for 360 mines and equipment
100 tons for radars and electronic equipment
50 tons growth

Electronic Equipment
Radio Location Set Type 273 Aerial Search
Radio Location Set Type 274 High Definition Surface Search
Radio Location Director Type 285M two on main directors
Radio Location Director Type 282M three on secondary directors
HF/DF Type 292
Passive Radio Intercept Type 293 (P, Q, M and O)
Passive Radio Location Intercept Type 294 (294, M & 0)

While far more seaworthy and featuring better protection, the alternative design still seems far too large an investment for the return.

For offensive minelaying in disputed waters the vessel is far larger than it needs to be, and for defensive mining, it is far faster than required.