WesWorld

Hello, What do you think of this design.....well, if I understnad the report correctly, this design is a huge piece of sh***
Maybe you guys can give me some recommendations how it can be done better.....



Wroclaw Class, Poland Destroyer laid down 1941

Displacement:
2.251 t light; 2.314 t standard; 2.407 t normal; 2.480 t full load

Dimensions: Length overall / water x beam x draught
353,39 ft / 344,91 ft x 40,35 ft x 15,09 ft (normal load)
107,71 m / 105,13 m x 12,30 m x 4,60 m

Armament:
6 - 3,94" / 100 mm guns in single mounts, 30,51lbs / 13,84kg shells, 1941 Model
Dual purpose guns in deck mounts
on centreline ends, evenly spread, 3 raised mounts - superfiring
8 - 0,79" / 20,0 mm guns in single mounts, 0,24lbs / 0,11kg shells, 1941 Model
Anti-aircraft guns in deck mount
on side amidships, 2 raised mounts - superfiring
2 guns in hull casemates - Limited use in heavy seas
4 - 0,50" / 12,7 mm guns in single mounts, 0,06lbs / 0,03kg shells, 1941 Model
Machine guns in deck mounts
on side, evenly spread
4 guns in hull casemates - Limited use in heavy seas
Weight of broadside 185 lbs / 84 kg
Shells per gun, main battery: 150
5 - 20,9" / 530 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0,79" / 20 mm 0,79" / 20 mm -
2nd: 0,20" / 5 mm - -

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 43.607 shp / 32.531 Kw = 33,56 kts
Range 3.000nm at 12,00 kts
Bunker at max displacement = 166 tons

Complement:
171 - 223

Cost:
£1,576 million / $6,305 million

Distribution of weights at normal displacement:
Armament: 23 tons, 1,0%
Armour: 14 tons, 0,6%
- Belts: 0 tons, 0,0%
- Torpedo bulkhead: 0 tons, 0,0%
- Armament: 14 tons, 0,6%
- Armour Deck: 0 tons, 0,0%
- Conning Tower: 0 tons, 0,0%
Machinery: 1.120 tons, 46,5%
Hull, fittings & equipment: 1.053 tons, 43,8%
Fuel, ammunition & stores: 156 tons, 6,5%
Miscellaneous weights: 40 tons, 1,7%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1.411 lbs / 640 Kg = 46,2 x 3,9 " / 100 mm shells or 0,5 torpedoes
Stability (Unstable if below 1.00): 1,19
Metacentric height 1,8 ft / 0,5 m
Roll period: 12,7 seconds
Steadiness - As gun platform (Average = 50 %): 57 %
- Recoil effect (Restricted arc if above 1.00): 0,11
Seaboat quality (Average = 1.00): 0,92

Hull form characteristics:
Hull has rise forward of midbreak, low quarterdeck
and transom stern
Block coefficient: 0,401
Length to Beam Ratio: 8,55 : 1
'Natural speed' for length: 21,78 kts
Power going to wave formation at top speed: 70 %
Trim (Max stability = 0, Max steadiness = 100): 62
Bow angle (Positive = bow angles forward): 20,00 degrees
Stern overhang: 0,00 ft / 0,00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 23,29 ft / 7,10 m
- Forecastle (15%): 22,31 ft / 6,80 m
- Mid (40%): 18,04 ft / 5,50 m (14,76 ft / 4,50 m aft of break)
- Quarterdeck (12%): 11,48 ft / 3,50 m (14,76 ft / 4,50 m before break)
- Stern: 11,48 ft / 3,50 m
- Average freeboard: 16,91 ft / 5,16 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 159,6%
- Above water (accommodation/working, high = better): 124,4%
Waterplane Area: 8.897 Square feet or 827 Square metres
Displacement factor (Displacement / loading): 95%
Structure weight / hull surface area: 62 lbs/sq ft or 303 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,85
- Longitudinal: 4,10
- Overall: 0,99
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is excellent
Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

Well picking a DD for a first go is a interesting move....

SS was orignialy designed to sim BBs and big cruisers, so for DDs there are some additional rules.

Hull strength (Relative):
- Cross-sectional: 0,85
- Longitudinal: 4,10
- Overall: 0,99

You see this section here? I bold faced the Cross-sectional part because thats what matters with DDs. As long as that number does not drop below .5, you are good, so you still have some strength to play with.

The only other number that jumps out at me is the seakeeping, I bold faced it below.

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1.411 lbs / 640 Kg = 46,2 x 3,9 " / 100 mm shells or 0,5 torpedoes
Stability (Unstable if below 1.00): 1,19
Metacentric height 1,8 ft / 0,5 m
Roll period: 12,7 seconds
Steadiness - As gun platform (Average = 50 %): 57 %
- Recoil effect (Restricted arc if above 1.00): 0,11
Seaboat quality (Average = 1.00): 0,92

The fact that the number is below 1.00 would be conserning to me if this ship was not a destroyer. DDs are never going to be good seaboats in comparison to a BB, so IMO (others may differ) this is sort of irreverent for DDs. If you want to make the raising better, try raising the freeboard.

Onto the design itself. Your main battery is way to light. 6x120mm should be more then possible. This will give it a more comparable punch to more modern types in larger Navies (and the same main battery as Thailiand's best DD) I would see if adding hoists to the gun is posible, as that will improve there RoF. Also, the rounds per gun should be raised from 150 to 250-300 range IMO to provide for more time in action. The MGs should not be in hull casemates as that basically eliminates them as useful AA weapons. IMO, they are to light and should be replaced with more 20mm. Eight 530mm torpedoes should be more then possible in 2 quad launchers, but I think that ten tubes in two quintuple launchers would work on this hull as well.

With your freeboard, is there a reason why you adopted a lower stern along with a stepped deck?

Overall, not bad for a first go. You picked a very hard type of ship to design and did not do bad. You still have plenty of strength left over to make this a good DD. A final question, do you have access to Conways All the Worlds Fighting Ships?

Hello, thanks a lot for your comment, snip. I don't have acces to that book you mentioned.
Well concernig the main armament....I want this ship to have Akizuki-like dual porpuse turrets....100mm should be enough to knock most destroyers and enemy small vessels out. Engagment of ships bigger than destroyers would be done by a naval air arm.

If the armament layout of the Akizuki is what you imagined, they should be contained in twin mounts. To do that, go to the "Weapons" tab of Springsharp and indicate the number of mounts the guns are contained in.

For example: You have specified six 100m DP guns on the "Guns" tab as the main battery. If you go to the "Weapons" tab it defaults to the same number; if you want to specify twin mounts, enter 3; that will reduce the number of mounts. You will then have to select the layout of the mounts - which in the the Akizuki's case would be "Centerline-ends - Fore>Aft"

This will help with the topweight of the vessel and free deck space for other equipment.

With the size of most modern destroyers 120mm guns are going to be needed to knock them out. Some have gone up to 150mm guns for there DDs. Also for DP use, 100mm is a little light for engaging modern aircraft.

Actually, I'd say 100mm DP is excellent for engaging aircraft, probably just as good or better than a 120mm. Anything in the 75-130mm range is good for engaging aircraft, so long as the MV and elevation is high and the ROF is decent.

Pardon my bias, Im a bit of a 5"/38 fanboy

Quoted

Originally posted by snip
Pardon my bias, Im a bit of a 5"/38 fanboy

If you have a weapon as formidable as the 5"/L38, then you'd want to use it, naturally. But a 100mm shell will still deal a one-shot stop to any aircraft in existence.

I went to the Naval Weapons Page to refresh my memory on the IJN Type 98 10cm/65 gun.

This weapon is truly formidable. While certainly lighter than the 5in/38 in a surface role, I would still not want to be on the receiving end of a sextet of these weapons. And as for an AA weapon, they seem far superior to the 5in/38.

If Daidalos envisions his destroyer in the primarily AA role - and given the confined waters of the Baltic and the number of aircraft there is not unreasonable - I think the 100mm main armament for his design is a sound choice.

After looking over the stats, I agree that it would make a formidable DP/AA weapon. However, I would argue for increasing the number of guns to eight to provide a higher volume of fire for surface and air engagements. As it stands now, his hull has the strength to take on the additional load and I dont think that fitting in an additional twin mount would be a design-breaking issue from the deck space standpoint.

If a 6 gun arrangement is desired, then I strongly suggest ether an increase to 120-130mm guns or making the design cheaper to allow for more hulls to be built. ~2,000 tons is an expensive hull for only 6x100mm, no matter how good the gun.

After messing around with springsharp i decided to modify my first design. The 100 mm guns will stay, but as snip suggested there will be four twin mounts instead of 3. THe ship will be a little bit longer and additional 20 mm AA guns are installed.
What do you think?
Is the added armor realistic on a destroyer? I'm not famniliar with destroyer armour but I felt that due to the fact that mines are a mayor threat in the baltic sea, the ship needs some protection.....



Wroclaw II Class, Poland Destroyer laid down 1941

Displacement:
2.466 t light; 2.564 t standard; 2.664 t normal; 2.745 t full load

Dimensions: Length overall / water x beam x draught
386,20 ft / 377,72 ft x 40,03 ft x 15,42 ft (normal load)
117,71 m / 115,13 m x 12,20 m x 4,70 m

Armament:
8 - 3,94" / 100 mm guns (4x2 guns), 30,51lbs / 13,84kg shells, 1941 Model
Dual purpose guns in deck mounts
on centreline ends, evenly spread, 3 raised mounts - superfiring
14 - 0,79" / 20,0 mm guns (7x2 guns), 0,24lbs / 0,11kg shells, 1941 Model
Anti-aircraft guns in deck mounts
on side, all amidships, all raised mounts - superfiring
2 - 0,50" / 12,7 mm guns in single mounts, 0,06lbs / 0,03kg shells, 1941 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 248 lbs / 112 kg
Shells per gun, main battery: 320
8 - 20,9" / 530 mm above water torpedoes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 0,39" / 10 mm 328,08 ft / 100,00 m 9,84 ft / 3,00 m
Ends: 0,39" / 10 mm 39,37 ft / 12,00 m 9,84 ft / 3,00 m
10,27 ft / 3,13 m Unarmoured ends
Upper: 0,20" / 5 mm 328,08 ft / 100,00 m 9,84 ft / 3,00 m
Main Belt covers 134% of normal length
Main belt does not fully cover magazines and engineering spaces

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0,20" / 5 mm 0,20" / 5 mm -
2nd: 0,20" / 5 mm - -

- Armour deck: 0,31" / 8 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 44.772 shp / 33.400 Kw = 33,65 kts
Range 3.000nm at 12,00 kts
Bunker at max displacement = 180 tons

Complement:
185 - 241

Cost:
£1,694 million / $6,775 million

Distribution of weights at normal displacement:
Armament: 31 tons, 1,2%
Armour: 142 tons, 5,3%
- Belts: 81 tons, 3,0%
- Torpedo bulkhead: 0 tons, 0,0%
- Armament: 4 tons, 0,2%
- Armour Deck: 56 tons, 2,1%
- Conning Tower: 0 tons, 0,0%
Machinery: 1.155 tons, 43,3%
Hull, fittings & equipment: 1.088 tons, 40,8%
Fuel, ammunition & stores: 198 tons, 7,4%
Miscellaneous weights: 50 tons, 1,9%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1.468 lbs / 666 Kg = 48,1 x 3,9 " / 100 mm shells or 0,5 torpedoes
Stability (Unstable if below 1.00): 1,06
Metacentric height 1,4 ft / 0,4 m
Roll period: 14,1 seconds
Steadiness - As gun platform (Average = 50 %): 75 %
- Recoil effect (Restricted arc if above 1.00): 0,19
Seaboat quality (Average = 1.00): 0,97

Hull form characteristics:
Hull has raised forecastle, rise forward of midbreak
and transom stern
Block coefficient: 0,400
Length to Beam Ratio: 9,44 : 1
'Natural speed' for length: 22,59 kts
Power going to wave formation at top speed: 66 %
Trim (Max stability = 0, Max steadiness = 100): 77
Bow angle (Positive = bow angles forward): 20,00 degrees
Stern overhang: 0,00 ft / 0,00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 23,29 ft / 7,10 m
- Forecastle (15%): 20,34 ft / 6,20 m (19,69 ft / 6,00 m aft of break)
- Mid (40%): 18,04 ft / 5,50 m (13,78 ft / 4,20 m aft of break)
- Quarterdeck (12%): 13,78 ft / 4,20 m
- Stern: 13,78 ft / 4,20 m
- Average freeboard: 16,21 ft / 4,94 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 152,2%
- Above water (accommodation/working, high = better): 98,8%
Waterplane Area: 9.658 Square feet or 897 Square metres
Displacement factor (Displacement / loading): 95%
Structure weight / hull surface area: 60 lbs/sq ft or 294 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,84
- Longitudinal: 2,96
- Overall: 0,95
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform
Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

Quoted

Originally posted by Daidalos
Is the added armor realistic on a destroyer? I'm not famniliar with destroyer armour but I felt that due to the fact that mines are a mayor threat in the baltic sea, the ship needs some protection.....

The kind of armour needed to protect from a naval mine would not really be viable on a destroyer-sized vessel. You'd need extensive underwater protection to protect the hull from the shock of an exploding mine; that would be extremely difficult due to the space on a DD.

All things considered the inclusion of deck and belt armor on a destroyer is a waste. I would recommend that you confine armor on a destroyer to the guns and their mounts, and perhaps the conning tower.

The design still has stability and seakeeping issues. To address that, I would reduce the number of superfiring mounts in the main battery from 3 to 2; that would reduce some of the topweight.

It seems that far more of your hull is below water than is desirable, and less above. Adjusting the freeboard might address that issue.

The design has a considerable reserve of strength left - and I would seriously suggest increasing the cruise speed to 15 knots and increasing the radius - which will increase your requirements for bunkers but contribute positively to stability.

In addition to Bruce's comments about seakeeping, I would make the design with a low quarterdeck as opposed to a mid break. you have the strength left in the hull to do both that and raise the range. Give me a bit for things to calm down at work and I may be able to provide a sim for you to look at. Not that Im any good at DDs...

Wroclaw II Class, Poland Destroyer laid down 1941

Displacement:
2.198 t light; 2.291 t standard; 2.438 t normal; 2.555 t full load

Dimensions: Length overall / water x beam x draught
386,44 ft / 377,72 ft x 40,03 ft x 14,11 ft (normal load)
117,79 m / 115,13 m x 12,20 m x 4,30 m

Armament:
8 - 3,94" / 100 mm guns (4x2 guns), 30,51lbs / 13,84kg shells, 1941 Model
Dual purpose guns in deck mounts
on centreline ends, evenly spread, 2 raised mounts - superfiring
14 - 0,79" / 20,0 mm guns (7x2 guns), 0,24lbs / 0,11kg shells, 1941 Model
Anti-aircraft guns in deck mounts
on side, all amidships, all raised mounts - superfiring
2 - 0,50" / 12,7 mm guns in single mounts, 0,06lbs / 0,03kg shells, 1941 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 248 lbs / 112 kg
Shells per gun, main battery: 320
8 - 20,9" / 530 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0,20" / 5 mm 0,20" / 5 mm -
2nd: 0,20" / 5 mm - -

- Conning tower: 0,16" / 4 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 42.281 shp / 31.541 Kw = 33,65 kts
Range 3.000nm at 15,00 kts
Bunker at max displacement = 263 tons

Complement:
173 - 225

Cost:
£1,584 million / $6,334 million

Distribution of weights at normal displacement:
Armament: 31 tons, 1,3%
Armour: 5 tons, 0,2%
- Belts: 0 tons, 0,0%
- Torpedo bulkhead: 0 tons, 0,0%
- Armament: 4 tons, 0,2%
- Armour Deck: 0 tons, 0,0%
- Conning Tower: 1 tons, 0,0%
Machinery: 1.095 tons, 44,9%
Hull, fittings & equipment: 1.017 tons, 41,7%
Fuel, ammunition & stores: 240 tons, 9,8%
Miscellaneous weights: 50 tons, 2,1%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1.342 lbs / 609 Kg = 44,0 x 3,9 " / 100 mm shells or 0,5 torpedoes
Stability (Unstable if below 1.00): 1,17
Metacentric height 1,7 ft / 0,5 m
Roll period: 12,9 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0,17
Seaboat quality (Average = 1.00): 1,04

Hull form characteristics:
Hull has raised forecastle, rise forward of midbreak, low quarterdeck
and transom stern
Block coefficient: 0,400
Length to Beam Ratio: 9,44 : 1
'Natural speed' for length: 22,59 kts
Power going to wave formation at top speed: 66 %
Trim (Max stability = 0, Max steadiness = 100): 68
Bow angle (Positive = bow angles forward): 20,00 degrees
Stern overhang: 0,00 ft / 0,00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 23,95 ft / 7,30 m
- Forecastle (15%): 20,34 ft / 6,20 m (19,69 ft / 6,00 m aft of break)
- Mid (40%): 18,04 ft / 5,50 m (14,76 ft / 4,50 m aft of break)
- Quarterdeck (12%): 12,47 ft / 3,80 m (14,76 ft / 4,50 m before break)
- Stern: 12,47 ft / 3,80 m
- Average freeboard: 16,57 ft / 5,05 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 158,2%
- Above water (accommodation/working, high = better): 110,0%
Waterplane Area: 9.658 Square feet or 897 Square metres
Displacement factor (Displacement / loading): 96%
Structure weight / hull surface area: 57 lbs/sq ft or 276 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,79
- Longitudinal: 2,97
- Overall: 0,90
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform

This revised design is much improved. However, the level of armor specified is very light. I would suggest a minimum of 20mm on the main gun houses and a similar minimum of 20mm on the conning tower. Armor should be provided for the main gun hoists as well.

The design has a lot of reserve strength in it, and I think that an increase in the block coefficient might help in the stability issues you are having. It may cost some tonnage, but I think it will pay dividends in the long run.

Getting better. The one thing that still stands out to me as odd is the freeboard. As it is now, you have three deck breaks. I cant recall a ship with that feature, tho others are free to correct me on this.

This is your ships freeboard.

Freeboard (% = measuring location as a percentage of overall length):
- Stem: 23,95 ft / 7,30 m
- Forecastle (15%): 20,34 ft / 6,20 m (19,69 ft / 6,00 m aft of break)
- Mid (40%): 18,04 ft / 5,50 m (14,76 ft / 4,50 m aft of break)
- Quarterdeck (12%): 12,47 ft / 3,80 m (14,76 ft / 4,50 m before break)
- Stern: 12,47 ft / 3,80 m

What I would do is make it a "proper" Stepdecker. This means that your forcastle and fordeck would be at the same level with the aft deck and stern being lower, but on the same level. An example is below.

Freeboard (% = measuring location as a percentage of overall length):
- Stem: 22.97 ft / 7.00 m
- Forecastle (20 %): 19.69 ft / 6.00 m
- Mid (50 %): 19.69 ft / 6.00 m (12.47 ft / 3.80 m aft of break)
- Quarterdeck (15 %): 12.47 ft / 3.80 m
- Stern: 12.47 ft / 3.80 m
- Average freeboard: 16.34 ft / 4.98 m

Another opption would be to have the hull be a flushdecker with a low quarterdeck for any stern launched ASW weapons. That would look like this:

Freeboard (% = measuring location as a percentage of overall length):
- Stem: 22.97 ft / 7.00 m
- Forecastle (20 %): 19.69 ft / 6.00 m
- Mid (50 %): 19.69 ft / 6.00 m
- Quarterdeck (15 %): 12.47 ft / 3.80 m (19.69 ft / 6.00 m before break)
- Stern: 12.47 ft / 3.80 m
- Average freeboard: 18.86 ft / 5.75 m

Seeing as you still have some cross sectional strenght left to play with, I dont think any of these changes would break the design.

Quoted

Originally posted by BruceDuncan
The design has a lot of reserve strength in it, and I think that an increase in the block coefficient might help in the stability issues you are having. It may cost some tonnage, but I think it will pay dividends in the long run.

Increasing the block coefficient to 0.42 and doubling the range would likely be a good trade-off.

Thanks so far, I will modify this design again... but with the range....whatfor do i need 4000 nm range for a ship which most likely will never leave the baltic see?

Quoted

Originally posted by Daidalos
Thanks so far, I will modify this design again... but with the range....whatfor do i need 4000 nm range for a ship which most likely will never leave the baltic see?

Having more fuel aboard offers more flexibility with high-speed steaming. For instance, if you look at my Bulgarian Drazki-class destroyers, you may note that I've calculated out steaming distances at a large range of speeds:

Quoted

Range 12,800nm at 10.00 kts
Range 5,400nm at 15.00 kts
Range 3,535nm at 18.00 kts
Range 2,730nm at 20.00 kts
Range 1,521nm at 25.00 kts
Range 903nm at 30.00 kts
Range 632nm at 33.75 kts

While my Bulgarian destroyers generally cruise at speeds of 15-18 knots, in wartime the ships will almost never operate at those slower cruising speeds: they will be steaming at higher speeds for extended periods - for instance evading shore-based air attacks, where speed is life and the ability to continue steaming at that speed is valued.

I'd have to sim the design myself to make sure, but I'd wager that with 3000nm range at 15 knots, your vessel would be good for only five to eight hours of high-speed steaming before she'd need to be refueled.