WesWorld

Hi folks,

I need your help and advise.

The RSAN Tyrfing, a 8,000ts CDS, is due for modernizatzion. However, I have no idea what kind of rebuild I should plan her for. Usually, I would update AA armament and keep her for another decade for minimum costs. But I sense I should better check other options, too.

She features powerful 25cm guns but otherwise she offers little special. Her armor was designed to protect her against gunfire up to 15cm caliber and she features a spotter plane. The general layout and doctrine made the vessel a good escort or convoy ship but somehow she is neither fish nor flesh.

So one option is to rebuild her in a way to make a heavy cruiser of her. This would allow to make use of her powerful main armament and add numbers in a category the RSAN is not well represented. However, when I tried to raise speed to 30+ knots by use of 1943er turbines, the result was a very low hull strength. In answer to that problem I decided to cut her in half and add a 30m segment to her hull. But even after that action I could not make the design work. Other modifications, btw, affected the ships secondary armament which was replaced by 16 new 75mm automatic single mounts.

Maybe you can help me? Any ideas how to transform the CDS into a heavy cruiser? Any other ideas?

Thanks,

HoOmAn

After looking at the sim, I have a bit of a feeling that whatever is necessary to turn the Tyrfing into a heavy cruiser will make for a pretty expensive conversion job in-game, and to me, it would probably be a more expensive job than I'd want to pay for. I'd presume the hull form, freeboard, and such were all designed with the slower speeds in mind; I also note the ship has a small TDS.

While turning her into a CA might result in a pretty potent little ship, I'd probably think more along different lines, myself. Perhaps make her a command ship for an amphibious flotilla; her guns could be used for land bombardment, and her armour would protect her against medium-sized shore artillery. Or perhaps a communications ship, or a dedicated experimental ship? If it was 1948 or later, I'd almost suggest the sort of work the USN did aboard the Mississippi.

But I'll see if I can't figure out some sort of CA improvements anyway.

The problem appears to be that you designed it for minimum seakeeping as a CDS. That makes it reallly, really hard to increase speed.

Quoted

Tyrfring, SAE Light Heavy Crusier laid down 1928 (Engine 1943)

Displacement:
9,314 t light; 9,788 t standard; 10,412 t normal; 10,911 t full load

Dimensions: Length overall / water x beam x draught
597.11 ft / 597.11 ft x 68.90 ft x 14.76 ft (normal load)
182.00 m / 182.00 m x 21.00 m x 4.50 m

Armament:
6 - 9.84" / 250 mm guns (2x3 guns), 476.75lbs / 216.25kg shells, 1928 Model
Breech loading guns in turrets (on barbettes)
on centreline ends, evenly spread
16 - 2.95" / 75.0 mm guns in single mounts, 12.87lbs / 5.84kg shells, 1943 Model
Automatic rapid fire guns in deck mounts with hoists
on side, all amidships, 8 raised mounts - superfiring
16 - 1.57" / 40.0 mm guns (4x4 guns), 1.95lbs / 0.89kg shells, 1928 Model
Anti-aircraft guns in deck mounts
on side, evenly spread
12 - 0.79" / 20.0 mm guns (6x2 guns), 0.24lbs / 0.11kg shells, 1928 Model
Machine guns in deck mounts
on side, evenly spread
Weight of broadside 3,101 lbs / 1,406 kg
Shells per gun, main battery: 150
6 - 0.8" / 21 mm above water torpedoes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 4.72" / 120 mm 368.64 ft / 112.36 m 10.17 ft / 3.10 m
Ends: 4.72" / 120 mm 89.24 ft / 27.20 m 10.17 ft / 3.10 m
139.23 ft / 42.44 m Unarmoured ends
Main Belt covers 95 % of normal length
Main belt does not fully cover magazines and engineering spaces

- Torpedo Bulkhead:
0.98" / 25 mm 368.64 ft / 112.36 m 9.19 ft / 2.80 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 7.09" / 180 mm 3.54" / 90 mm 4.72" / 120 mm
2nd: 0.79" / 20 mm 0.39" / 10 mm -
3rd: 0.59" / 15 mm - -
4th: 0.39" / 10 mm - -

- Armour deck: 1.57" / 40 mm, Conning tower: 5.91" / 150 mm

Machinery:
Diesel Internal combustion motors,
Geared drive, 4 shafts, 56,774 shp / 42,354 Kw = 28.20 kts
Range 8,000nm at 12.00 kts
Bunker at max displacement = 1,123 tons

Complement:
514 - 669

Cost:
£3.288 million / $13.152 million

Distribution of weights at normal displacement:
Armament: 393 tons, 3.8 %
Armour: 2,351 tons, 22.6 %
- Belts: 916 tons, 8.8 %
- Torpedo bulkhead: 123 tons, 1.2 %
- Armament: 374 tons, 3.6 %
- Armour Deck: 877 tons, 8.4 %
- Conning Tower: 61 tons, 0.6 %
Machinery: 1,466 tons, 14.1 %
Hull, fittings & equipment: 5,054 tons, 48.5 %
Fuel, ammunition & stores: 1,098 tons, 10.5 %
Miscellaneous weights: 50 tons, 0.5 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
18,624 lbs / 8,448 Kg = 39.1 x 9.8 " / 250 mm shells or 3.0 torpedoes
Stability (Unstable if below 1.00): 1.25
Metacentric height 4.3 ft / 1.3 m
Roll period: 14.0 seconds
Steadiness - As gun platform (Average = 50 %): 53 %
- Recoil effect (Restricted arc if above 1.00): 0.39
Seaboat quality (Average = 1.00): 0.92

Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0.600
Length to Beam Ratio: 8.67 : 1
'Natural speed' for length: 24.44 kts
Power going to wave formation at top speed: 52 %
Trim (Max stability = 0, Max steadiness = 100): 57
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: 21.82 ft / 6.65 m
- Forecastle (20 %): 19.23 ft / 5.86 m
- Mid (70 %): 19.23 ft / 5.86 m (11.35 ft / 3.46 m aft of break)
- Quarterdeck (15 %): 11.35 ft / 3.46 m
- Stern: 11.35 ft / 3.46 m
- Average freeboard: 17.07 ft / 5.20 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 107.1 %
- Above water (accommodation/working, high = better): 194.1 %
Waterplane Area: 30,089 Square feet or 2,795 Square metres
Displacement factor (Displacement / loading): 123 %
Structure weight / hull surface area: 126 lbs/sq ft or 613 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.07
- Longitudinal: 0.97
- 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

It might work as a ship for, say, Camroon, but I don't think it's worth it.

EDIT: The SS seakeeping thing isn't, and shouldn't be considered accurate. It IS a good seaboat as long as you keep it below 26 knots or so in handling; if you want to squeeze those extra 2 knots out, it wouldn't be a good idea to do it in heavy weather. Our ships seem to have MUCH superior seakeeping abilities then OTL ships.

Quoted

Originally posted by TexanCowboy
6 - 0.8" / 21 mm above water torpedoes

D'aw, what cute little torpedoes!

I would simply refit the Tyrfing with the AA improvements you mention. Keep her for bombardment and command duties. If you want to increase your CA numbers then build new proper ones than this rather clumsy attempt to make a Jaguar out of a Trabant and a Lada!

Heh! She is either Trabant nor Lada! A little bit more respect, please. :o)

Seriously, the idea of turning her into a CA kicks me most. That´s why I came up with it. I´d also accept a slightly reduced seakeeping for the same reason Texan stated. However, to be able to act as a CA and to operate with the fleet, she needs at least a speed of 30 knots. If that is impossible - and her original hull form might be a reason - I better check other options.

How would a command ship for amphibious assaults look like? Any proposals?

Btw, here is my attempt. It includes a thinned but lenghened belt (the new midship sections needs to be armored too) and no torpedos.

Tyrfing rebuild concept, South African Coast Defence Ship laid down 1928 (Engine 1943)

Displacement:
9.594 t light; 10.104 t standard; 10.875 t normal; 11.492 t full load

Dimensions: Length overall / water x beam x draught
611,10 ft / 597,11 ft x 68,90 ft x 15,42 ft (normal load)
186,26 m / 182,00 m x 21,00 m x 4,70 m

Armament:
6 - 9,84" / 250 mm guns (2x3 guns), 524,70lbs / 238,00kg shells, 1928 Model
Breech loading guns in turrets (on barbettes)
on centreline ends, evenly spread
18 - 2,95" / 75,0 mm guns (16 mounts), 12,87lbs / 5,84kg shells, 1943 Model
Automatic rapid fire guns in deck mounts with hoists
on side, all amidships, 8 raised mounts - superfiring
12 - 1,57" / 40,0 mm guns (6x2 guns), 1,95lbs / 0,88kg shells, 1943 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
12 - 0,79" / 20,0 mm guns (2x6 guns), 0,24lbs / 0,11kg shells, 1935 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 3.406 lbs / 1.545 kg
Shells per gun, main battery: 150

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 3,15" / 80 mm 482,28 ft / 147,00 m 10,17 ft / 3,10 m
Ends: Unarmoured
Main Belt covers 124% of normal length

- Torpedo Bulkhead:
0,98" / 25 mm 482,28 ft / 147,00 m 14,76 ft / 4,50 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 7,09" / 180 mm 3,54" / 90 mm 4,72" / 120 mm
2nd: 1,38" / 35 mm 0,98" / 25 mm 1,18" / 30 mm
3rd: 0,59" / 15 mm - -
4th: 0,39" / 10 mm - -

- Armour deck: 1,57" / 40 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 76.000 shp / 56.696 Kw = 30,16 kts
Range 6.000nm at 15,00 kts
Bunker at max displacement = 1.388 tons

Complement:
532 - 692

Cost:
£3,600 million / $14,401 million

Distribution of weights at normal displacement:
Armament: 396 tons, 3,6%
Armour: 2.168 tons, 19,9%
- Belts: 631 tons, 5,8%
- Torpedo bulkhead: 259 tons, 2,4%
- Armament: 401 tons, 3,7%
- Armour Deck: 877 tons, 8,1%
- Conning Tower: 0 tons, 0,0%
Machinery: 1.963 tons, 18,0%
Hull, fittings & equipment: 5.018 tons, 46,1%
Fuel, ammunition & stores: 1.281 tons, 11,8%
Miscellaneous weights: 50 tons, 0,5%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
14.965 lbs / 6.788 Kg = 31,4 x 9,8 " / 250 mm shells or 2,5 torpedoes
Stability (Unstable if below 1.00): 1,05
Metacentric height 3,1 ft / 1,0 m
Roll period: 16,4 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0,57
Seaboat quality (Average = 1.00): 0,83

Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0,600
Length to Beam Ratio: 8,67 : 1
'Natural speed' for length: 24,44 kts
Power going to wave formation at top speed: 56 %
Trim (Max stability = 0, Max steadiness = 100): 84
Bow angle (Positive = bow angles forward): 25,00 degrees
Stern overhang: 3,28 ft / 1,00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 22,97 ft / 7,00 m
- Forecastle (20%): 19,23 ft / 5,86 m
- Mid (70%): 19,23 ft / 5,86 m (11,35 ft / 3,46 m aft of break)
- Quarterdeck (15%): 11,35 ft / 3,46 m
- Stern: 11,35 ft / 3,46 m
- Average freeboard: 17,16 ft / 5,23 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 123,8%
- Above water (accommodation/working, high = better): 187,5%
Waterplane Area: 30.089 Square feet or 2.795 Square metres
Displacement factor (Displacement / loading): 117%
Structure weight / hull surface area: 124 lbs/sq ft or 604 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1,03
- Longitudinal: 0,99
- Overall: 1,00
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
Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

That seems to me like a 75% refit. IMO resources would be better used by building a real CA is the need for those type of ships exists. The only advantage I see is the construction time.

I'd kinda have to agree with Perdy, here. I've got anti-aircraft cruisers with that much belt and deck armour (though they don't have a torpedo belt).

Have you considered pulling the turrets and using them on a new hull, Vanguard-style?

Quoted

How would a command ship for amphibious assaults look like?

The main change would be allocating a couple of hundred tons for a command facility, such as a second bridge, for control of amphibious operations. This would include space for operations staff to work and additional communications equipment. She has to control both the amphibious task force at sea, and fire support (by gun and aircraft) for the operation on land.

You could do it with superstructure changes, for maybe a 25% refit (more than merely enclosing a bridge, but much less than replacing the whole superstructure)

She'd be good at it, with her armament, and her armor is more than sufficient for repelling fire from field artillery.

I suggest she avoids places with large-caliber coast artillery though.