WesWorld

I have tried again to design a destroyer - please feel free to offer suggestions for improvement. Looking at other designs it doesn't look that bad to me, but you all know more of what to look for. I'm particularly concerned about the 'poor seaboat' remark.

Project 39A - Pristina , Yugoslavian Destroyer laid down 1939

Displacement:
1,657 t light; 1,733 t standard; 1,901 t normal; 2,035 t full load

Dimensions: Length overall / water x beam x draught
384.42 ft / 374.02 ft x 35.99 ft x 12.20 ft (normal load)
117.17 m / 114.00 m x 10.97 m x 3.72 m

Armament:
4 - 4.72" / 120 mm guns in single mounts, 52.72lbs / 23.92kg shells, 1936 Model
Dual purpose guns in deck mounts with hoists
on centreline ends, evenly spread, all raised mounts - superfiring
4 - 1.57" / 40.0 mm guns (2x2 guns), 1.95lbs / 0.89kg shells, 1936 Model
Anti-aircraft guns in deck mounts
on side, all amidships, all raised mounts - superfiring
8 - 0.79" / 20.0 mm guns (4x2 guns), 0.24lbs / 0.11kg shells, 1928 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 221 lbs / 100 kg
Shells per gun, main battery: 300
10 - 21.7" / 550 mm above water torpedoes

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

- Conning tower: 1.57" / 40 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 42,719 shp / 31,868 Kw = 35.00 kts
Range 4,000nm at 15.00 kts
Bunker at max displacement = 302 tons

Complement:
143 - 187

Cost:
£1.247 million / $4.988 million

Distribution of weights at normal displacement:
Armament: 28 tons, 1.5 %
Armour: 21 tons, 1.1 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 16 tons, 0.9 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 5 tons, 0.3 %
Machinery: 951 tons, 50.0 %
Hull, fittings & equipment: 607 tons, 31.9 %
Fuel, ammunition & stores: 244 tons, 12.8 %
Miscellaneous weights: 50 tons, 2.6 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
574 lbs / 261 Kg = 10.9 x 4.7 " / 120 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.30
Metacentric height 1.7 ft / 0.5 m
Roll period: 11.5 seconds
Steadiness - As gun platform (Average = 50 %): 49 %
- Recoil effect (Restricted arc if above 1.00): 0.34
Seaboat quality (Average = 1.00): 0.97

Hull form characteristics:
Hull has rise forward of midbreak
and transom stern
Block coefficient: 0.405
Length to Beam Ratio: 10.39 : 1
'Natural speed' for length: 22.28 kts
Power going to wave formation at top speed: 67 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 22.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 25.75 ft / 7.85 m
- Forecastle (20 %): 20.51 ft / 6.25 m
- Mid (40 %): 20.51 ft / 6.25 m (12.01 ft / 3.66 m aft of break)
- Quarterdeck (15 %): 12.01 ft / 3.66 m
- Stern: 12.01 ft / 3.66 m
- Average freeboard: 15.83 ft / 4.82 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 176.6 %
- Above water (accommodation/working, high = better): 76.6 %
Waterplane Area: 8,625 Square feet or 801 Square metres
Displacement factor (Displacement / loading): 73 %
Structure weight / hull surface area: 36 lbs/sq ft or 177 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 1.89
- Overall: 0.57
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is cramped
Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

.97 seaboat rating is more than adequate for the Adriatic, actually.

Looking things over, it appears all the main guns are raised above deck level. I'd presume only superfiring guns would be raised thus. I'd also include more 40mm, but that's JMHO.

All main mounts are raised?

Other that that I cant see anything wrong with it.
0,97 is not that bad seaboat, not in Adriatic at least.

Quoted

Originally posted by Marek Gutkowski
All main mounts are raised?

Other that that I cant see anything wrong with it.
0,97 is not that bad seaboat, not in Adriatic at least.

The intent is to have B mount superfiring over A,
Y mount superfiring over X; where did I go wrong?

Quoted

Originally posted by BruceDuncan
The intent is to have B mount superfiring over A,
Y mount superfiring over X; where did I go wrong?

Put 2 mount as superfiring not all 4.

Quoted

Originally posted by BruceDuncan

Quoted

Originally posted by Marek Gutkowski
All main mounts are raised?

Other that that I cant see anything wrong with it.
0,97 is not that bad seaboat, not in Adriatic at least.

The intent is to have B mount superfiring over A,
Y mount superfiring over X; where did I go wrong?

That'd be demonstrated as 2 guns raised, rather than four.

"Raised" mounts generally refer to mounts higher than the level of the main deck. There's also an option to adding hull-mounted casemates but we're not in the best era for it.

Thank you for all the comments.

I've corrected the distribution of the main battery and increased the secondary. Other adjustments are noted at the bottom. She is still cramped; but I think that is a charge that can be laid against all destroyers.

Project 39B - Pristina , Yugoslavia Destroyer laid down 1939

Displacement:
1,677 t light; 1,755 t standard; 1,925 t normal; 2,060 t full load

Dimensions: Length overall / water x beam x draught
384.42 ft / 374.02 ft x 35.99 ft x 12.20 ft (normal load)
117.17 m / 114.00 m x 10.97 m x 3.72 m

Armament:
4 - 4.72" / 120 mm guns in single mounts, 52.72lbs / 23.91kg shells, 1936 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, 1936 Model
Anti-aircraft guns in deck mounts
on side, all amidships, all raised mounts - superfiring
8 - 0.79" / 20.0 mm guns (4x2 guns), 0.24lbs / 0.11kg shells, 1928 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 228 lbs / 104 kg
Shells per gun, main battery: 300
10 - 21.7" / 550 mm above water torpedoes

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

- Conning tower: 1.57" / 40 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 38,336 shp / 28,598 Kw = 34.00 kts
Range 4,000nm at 15.00 kts
Bunker at max displacement = 304 tons

Complement:
144 - 188

Cost:
£1.223 million / $4.892 million

Distribution of weights at normal displacement:
Armament: 29 tons, 1.5 %
Armour: 23 tons, 1.2 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 18 tons, 0.9 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 5 tons, 0.3 %
Machinery: 911 tons, 47.3 %
Hull, fittings & equipment: 664 tons, 34.5 %
Fuel, ammunition & stores: 248 tons, 12.9 %
Miscellaneous weights: 50 tons, 2.6 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
707 lbs / 321 Kg = 13.4 x 4.7 " / 120 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.26
Metacentric height 1.6 ft / 0.5 m
Roll period: 11.8 seconds
Steadiness - As gun platform (Average = 50 %): 55 %
- Recoil effect (Restricted arc if above 1.00): 0.32
Seaboat quality (Average = 1.00): 1.06

Hull form characteristics:
Hull has rise forward of midbreak
and transom stern
Block coefficient: 0.410
Length to Beam Ratio: 10.39 : 1
'Natural speed' for length: 22.26 kts
Power going to wave formation at top speed: 66 %
Trim (Max stability = 0, Max steadiness = 100): 52
Bow angle (Positive = bow angles forward): 22.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 25.75 ft / 7.85 m
- Forecastle (20 %): 20.51 ft / 6.25 m
- Mid (40 %): 20.51 ft / 6.25 m (12.01 ft / 3.66 m aft of break)
- Quarterdeck (15 %): 12.01 ft / 3.66 m
- Stern: 12.01 ft / 3.66 m
- Average freeboard: 15.83 ft / 4.82 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 168.3 %
- Above water (accommodation/working, high = better): 76.3 %
Waterplane Area: 8,653 Square feet or 804 Square metres
Displacement factor (Displacement / loading): 81 %
Structure weight / hull surface area: 40 lbs/sq ft or 193 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.56
- Longitudinal: 2.10
- Overall: 0.64
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is cramped

Corrected number of superfiring mounts
Slight reduction of speed
Changed bloc coefficient
Adjusted trim

I wonder about the side mounted 40mm.
Aside fro restriction in there arc I wonder will they fit side by side.

Then the lay out can be like this.
...o...o.
.o...o...

Centre line placament maybe a better choice.

Quoted

Originally posted by Marek Gutkowski
I wonder about the side mounted 40mm.
Aside fro restriction in there arc I wonder will they fit side by side.

Then the lay out can be like this.
...o...o.
.o...o...

Centre line placament maybe a better choice.

I do not think that I can get four mounts on the centerline given everything else. Quad mounts would be the answer but I don't know if that is pushing technology too far for a country like Yugoslavia. Right?

I used triples for 40mm.

Six 40mm guns is still a lot for 1600t DD.
I considered, the original design with four 40mm,sufficient.

One other thing about this ship, quintuple(five tubes) torpedo mount maybe overdoing it?
Also why 550mm Yugoslavia used 600mm or 480mm torpedo's. From what I remembered.

Quoted

Originally posted by Marek Gutkowski
I used triples for 40mm.

Six 40mm guns is still a lot for 1600t DD.
I considered, the original design with four 40mm,sufficient.

One other thing about this ship, quintuple(five tubes) torpedo mount maybe overdoing it?
Also why 550mm Yugoslavia used 600mm or 480mm torpedo's. From what I remembered.

40mmAA - Historically, no one ever did a triple mount - always pairs or quads. The only triple mount I recall is the Japanese 25mm, and that had some issues. I may play around with quad mounts, as they would fit the deck layout better, but she's still a project.

Torpedoes? Yugoslavia's current destroyer force is approaching block obsolescence, and as far as I am concerned a 600mm torpedo is a standoff weapon. I do not see the need for a standoff weapon at battle ranges I would expect in the Med or Adriatic; the 480mm torpedo is too small, too old in concept. So the RYN will be going with a mid-range 1930s favorite.

As you wish.
I'll stick to 600mm torpedo that is in development since 1929.
Yes it is an on old HSF calibre. All my "large" surface combatants use this calibre.

I'd say four 40mm is more than enough for a DD.

You could improve seakeeping by moving the hull break further aft, 40% seems a little short, I tend to go for 43-45% myself. Will cost some weight but might be worth it and give some extra hull space forward too.

Quoted

Originally posted by Hood
I'd say four 40mm is more than enough for a DD.

You could improve seakeeping by moving the hull break further aft, 40% seems a little short, I tend to go for 43-45% myself. Will cost some weight but might be worth it and give some extra hull space forward too.

I've tried to work in the excellent comments, and the results don't look too bad. Have I missed anything?

Project 39C - Pristina , Yugoslavia Destroyer laid down 1939

Displacement:
1,679 t light; 1,755 t standard; 1,925 t normal; 2,060 t full load

Dimensions: Length overall / water x beam x draught
384.42 ft / 374.02 ft x 35.99 ft x 12.20 ft (normal load)
117.17 m / 114.00 m x 10.97 m x 3.72 m

Armament:
4 - 4.72" / 120 mm guns in single mounts, 52.72lbs / 23.91kg shells, 1936 Model
Dual purpose guns in deck mounts with hoists
on centreline ends, evenly spread, 2 raised mounts - superfiring
4 - 1.57" / 40.0 mm guns (2x2 guns), 1.95lbs / 0.88kg shells, 1936 Model
Anti-aircraft guns in deck mounts
on centreline ends, evenly spread, all raised mounts - superfiring
8 - 0.79" / 20.0 mm guns (4x2 guns), 0.24lbs / 0.11kg shells, 1928 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 221 lbs / 100 kg
Shells per gun, main battery: 300
10 - 21.7" / 550 mm above water torpedoes

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

- Conning tower: 1.57" / 40 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 38,336 shp / 28,598 Kw = 34.00 kts
Range 4,000nm at 15.00 kts
Bunker at max displacement = 304 tons

Complement:
144 - 188

Cost:
£1.221 million / $4.883 million

Distribution of weights at normal displacement:
Armament: 28 tons, 1.4 %
Armour: 21 tons, 1.1 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 16 tons, 0.8 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 5 tons, 0.3 %
Machinery: 913 tons, 47.5 %
Hull, fittings & equipment: 667 tons, 34.6 %
Fuel, ammunition & stores: 246 tons, 12.8 %
Miscellaneous weights: 50 tons, 2.6 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
712 lbs / 323 Kg = 13.5 x 4.7 " / 120 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.25
Metacentric height 1.6 ft / 0.5 m
Roll period: 11.9 seconds
Steadiness - As gun platform (Average = 50 %): 58 %
- Recoil effect (Restricted arc if above 1.00): 0.34
Seaboat quality (Average = 1.00): 1.11

Hull form characteristics:
Hull has rise forward of midbreak
and transom stern
Block coefficient: 0.410
Length to Beam Ratio: 10.39 : 1
'Natural speed' for length: 22.26 kts
Power going to wave formation at top speed: 66 %
Trim (Max stability = 0, Max steadiness = 100): 52
Bow angle (Positive = bow angles forward): 22.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 25.75 ft / 7.85 m
- Forecastle (20 %): 20.51 ft / 6.25 m
- Mid (45 %): 20.51 ft / 6.25 m (12.01 ft / 3.66 m aft of break)
- Quarterdeck (15 %): 12.01 ft / 3.66 m
- Stern: 12.01 ft / 3.66 m
- Average freeboard: 16.25 ft / 4.95 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 168.2 %
- Above water (accommodation/working, high = better): 79.7 %
Waterplane Area: 8,653 Square feet or 804 Square metres
Displacement factor (Displacement / loading): 81 %
Structure weight / hull surface area: 39 lbs/sq ft or 190 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.55
- Longitudinal: 2.26
- Overall: 0.63
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is cramped

Miscellaneous Weight - 50 tons - reserved for design growth, Depth Charges, ASDIC etc.

Rev B: Corrected number of superfiring mounts
Rev B: Slight reduction of speed
Rev B:Changed bloc coefficient
Rev B: Adjusted trim
Rev C: Returned LAA outfit to two twin Bofors amidships, centerline
Rev C: Shifted Midbreak to 45%

Looking at the strength, you have some room for either shrinking the design or for (say) mine rails (might be useful in the Adriatic). What's the point of the trim being set to 52?

Quoted

Originally posted by Hrolf Hakonson
Looking at the strength, you have some room for either shrinking the design or for (say) mine rails (might be useful in the Adriatic). What's the point of the trim being set to 52?

The change in trim was one of the adjustments made to improve seaworthiness while maintaining stability.