WesWorld

With the incoming construction of 12 Z53 class destroyers, 18 Z25 ships will be retired from service as fleet destroyers.

This trusty class of ships, from a design dated in 1909, are in bad need of a refit, but won't go to the scrappers. Instead, they will be rebuilt during 1929 to adapt them to long range ASW escort service.

As such they will see their weapons changed from to 2x125mm DP mounts, one of the Torpedo Tubes mount erased, speed reduced to 24 knots (to put them out of the destroyer classification on the Cleito treaty), and the space freed by machinery and torpedo mount will be used to increase range and give free room for anti-submarine depth charges.

their AA battery will consist on 8x40mm and 8x20mm guns.


The Z25 destroyers as they are today:

Z25, Dutch Destroyer laid down 1909

Displacement:
1.505 t light; 1.554 t standard; 1.735 t normal; 1.873 t full load
Loading submergence 141 tons/feet

Dimensions:
295,28 ft x 29,86 ft x 16,40 ft (normal load)
90,00 m x 9,10 m x 5,00 m

Armament:
4 - 3,94" / 100 mm guns
3 - 2,95" / 75 mm guns
6 - 1,57" / 40 mm QF guns
2 - 0,51" / 13 mm guns
Weight of broadside 173 lbs / 78 kg
6 - 21,0" / 533,4 mm above water torpedoes

Armour:
Main gun shields 1,00" / 25 mm
Conning tower 1,00" / 25 mm

Machinery:
Oil fired boilers, steam turbines,
Direct drive, 2 shafts, 38.952 shp / 29.058 Kw = 32,00 kts
Range 5.500nm at 10,00 kts

Complement:
134 - 174

Cost:
£0,220 million / $0,880 million

Distribution of weights at normal displacement:
Armament: 22 tons, 1,2 %
Armour: 8 tons, 0,5 %
Belts: 0 tons, 0,0 %, Armament: 5 tons, 0,3 %, Armour Deck: 0 tons, 0,0 %
Conning Tower: 3 tons, 0,2 %, Torpedo bulkhead: 0 tons, 0,0 %
Machinery: 1.067 tons, 61,5 %
Hull, fittings & equipment: 359 tons, 20,7 %
Fuel, ammunition & stores: 230 tons, 13,3 %
Miscellaneous weights: 50 tons, 2,9 %

Metacentric height 1,2

Remarks:
Caution: Hull subject to strain in open-sea
Hull space for machinery, storage & compartmentation is extremely poor
Room for accommodation & workspaces is cramped

Estimated overall survivability and seakeeping ability:
Relative margin of stability: 1,22
Shellfire needed to sink: 254 lbs / 115 Kg = 8,3 x 3,9 " / 100 mm shells
(Approx weight of penetrating shell hits needed to sink ship excluding critical hits)
Torpedoes needed to sink: 0,2
(Approx number of typical torpedo hits needed to sink ship)
Relative steadiness as gun platform: 60 %
(Average = 50 %)
Relative rocking effect from firing to beam: 0,22
Relative quality as seaboat: 1,06

Hull form characteristics:
Block coefficient: 0,420
Sharpness coefficient: 0,30
Hull speed coefficient 'M': 7,51
'Natural speed' for length: 17,18 kts
Power going to wave formation at top speed: 70 %
Trim: 56
(Maximise stabilty/flotation = 0, Maximise steadiness/seakeeping = 100)

Estimated hull characteristics & strength:
Underwater volume absorbed by magazines and engineering spaces: 210,7 %
Relative accommodation and working space: 54,9 %
(Average = 100%)
Displacement factor: 46 %
(Displacement relative to loading factors)
Relative cross-sectional hull strength: 0,47
(Structure weight / hull surface area: 31 lbs / square foot or 154 Kg / square metre)
Relative longitudinal hull strength: 1,84
(for 14,76 ft / 4,50 m average freeboard, freeboard adjustment 4,10 ft)
Relative composite hull strength: 0,53




After the modifications:

Z25, Dutch Destroyer ASW Escort laid down 1909 (Engine 1929)

Displacement:
1.183 t light; 1.247 t standard; 1.735 t normal; 2.126 t full load

Dimensions: Length overall / water x beam x draught
300,10 ft / 295,28 ft x 29,86 ft x 16,40 ft (normal load)
91,47 m / 90,00 m x 9,10 m x 5,00 m

Armament:
2 - 4,92" / 125 mm guns in single mounts, 59,59lbs / 27,03kg shells, 1929 Model
Dual purpose guns in deck mounts
on centreline ends, evenly spread
8 - 1,57" / 40,0 mm guns (4x2 guns), 1,95lbs / 0,89kg shells, 1929 Model
Anti-aircraft guns in deck mounts
on side, all amidships
8 - 0,79" / 20,0 mm guns (4x2 guns), 0,24lbs / 0,11kg shells, 1929 Model
Anti-aircraft guns in deck mounts
on side, evenly spread
Weight of broadside 137 lbs / 62 kg
Shells per gun, main battery: 350
3 - 21,0" / 533,4 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0,79" / 20 mm 0,39" / 10 mm -
2nd: 0,39" / 10 mm - -
3rd: 0,39" / 10 mm - -

- Conning tower: 0,98" / 25 mm

Machinery:
Oil fired boilers, steam turbines,
Direct drive, 2 shafts, 11.655 shp / 8.695 Kw = 24,00 kts
Range 10.500nm at 15,00 kts
Bunker at max displacement = 879 tons

Complement:
133 - 174

Cost:
£0,106 million / $0,424 million

Distribution of weights at normal displacement:
Armament: 17 tons, 1,0 %
Armour: 8 tons, 0,5 %
- Belts: 0 tons, 0,0 %
- Torpedo bulkhead: 0 tons, 0,0 %
- Armament: 5 tons, 0,3 %
- Armour Deck: 0 tons, 0,0 %
- Conning Tower: 3 tons, 0,2 %
Machinery: 358 tons, 20,6 %
Hull, fittings & equipment: 650 tons, 37,5 %
Fuel, ammunition & stores: 552 tons, 31,8 %
Miscellaneous weights: 150 tons, 8,6 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
2.214 lbs / 1.004 Kg = 37,2 x 4,9 " / 125 mm shells or 0,8 torpedoes
Stability (Unstable if below 1.00): 1,15
Metacentric height 1,1 ft / 0,3 m
Roll period: 12,2 seconds
Steadiness - As gun platform (Average = 50 %): 72 %
- Recoil effect (Restricted arc if above 1.00): 0,16
Seaboat quality (Average = 1.00): 1,48

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0,420
Length to Beam Ratio: 9,89 : 1
'Natural speed' for length: 17,18 kts
Power going to wave formation at top speed: 55 %
Trim (Max stability = 0, Max steadiness = 100): 49
Bow angle (Positive = bow angles forward): 10,00 degrees
Stern overhang: 1,64 ft / 0,50 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 18,04 ft / 5,50 m
- Forecastle (20 %): 11,48 ft / 3,50 m
- Mid (55 %): 11,48 ft / 3,50 m
- Quarterdeck (15 %): 11,48 ft / 3,50 m
- Stern: 11,48 ft / 3,50 m
- Average freeboard: 12,01 ft / 3,66 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 85,6 %
- Above water (accommodation/working, high = better): 69,2 %
Waterplane Area: 5.496 Square feet or 511 Square metres
Displacement factor (Displacement / loading): 172 %
Structure weight / hull surface area: 56 lbs/sq ft or 274 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1,05
- Longitudinal: 3,49
- Overall: 1,18
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is cramped
Ship has slow, easy roll, a good, steady gun platform
Good seaboat, rides out heavy weather easily



The name of the class probably will change, as "Z" prefix is reserved for destroyers in the Royal Dutch Navy.

Change the weapons date to 1929 (or whenever that gun design was built), that should fix the problem.

you know when you get that strange feeling, sort of an of "I'm stupid" bouncing around your brain?...


well, that's just what I have now


Thanks for the "tip"...should've noticed it by myself

A good plan, it's the same thing I'm doing with my old destroyers (perhaps we've started the dreaded 'Sloop Race'?).

I like the increased range, it might be needed for oceanic escort work.

One question, though - aren't you using 5"/127 mm guns on the new destroyers? If so, why use 4.92"/125 mm guns here?

Quoted

Originally posted by The Rock Doctor


One question, though - aren't you using 5"/127 mm guns on the new destroyers? If so, why use 4.92"/125 mm guns here?

no, the new destroyers all sport 125mm DP guns, 1926 model. The Z45 class carries them, as does the future Z53 class.

since they have torpedos:



G. VESSELS NOT SUBJECT TO LIMITATIONS IN NUMBER AND/OR TONNAGE

I.

Subject to any special agreements which may submit them to
limitation, the following vessels are exempt from limitation:

(a) Naval surface combatant vessels of 600 tons (610 metric tons)
standard displacement and under;


(b) Naval surface combatant vessels exceeding 600 tons (610 metric
tons), but not exceeding 2,000 tons (2,032 metric tons) standard
displacement, provided they have none of the following
characteristics:
(1) Mount a gun above 5.1 inch (130 mm) calibre;
(2) Mount more than eight guns above 3 inch (76 mm) calibre;
(3) Are designed or fitted to launch torpedoes;
(4) Are designed for a speed greater than 24 knots.
(5) Are fitted to receive aircraft on board from the air.

Yes thats true, with torps they are still under CT limitations.

As for a sloop race I'm thinking of doing the same with the remaining Admiralty class DD's loitering arround, nice to see somebody beat me to it!

I do think torpedos are a pretty good thing for a convoy escort to have, since it will intimidate the hell out of surface raiders to have some escorts turn and start a torpedo run The last thing a raider needs is a big, water-sucking, fuel-draining, speed-reducing hole below the waterline. That's why I tend to favor 600 ton ships as escorts. An Escort Cruiser or Escort Carrier and a flotilla of these will cover a convoy against most threats. She'll pass for 600 tons, and has guns enough to fight a surfaced sub, torpedos for surface raiders, a bit of flak, and fair speed. They lack the range and survivability of the rebuilt Z25, and their ASW fit isn't as extensive:

Convoy escort laid down 1929

Displacement:
609 t light; 630 t standard; 844 t normal; 1,015 t full load

Dimensions: Length overall / water x beam x draught
266.92 ft / 250.98 ft x 24.31 ft x 11.53 ft (normal load)
81.36 m / 76.50 m x 7.41 m x 3.51 m

Armament:
1 - 3.94" / 100 mm guns in single mounts, 30.51lbs / 13.84kg shells, 1929 Model
Quick firing gun in deck mount
on centreline forward
2 - 1.46" / 37.0 mm guns (1x2 guns), 1.55lbs / 0.70kg shells, 1929 Model
Anti-aircraft guns in deck mount
on centreline aft
2 - 1.46" / 37.0 mm guns in single mounts, 1.55lbs / 0.70kg shells, 1929 Model
Anti-aircraft guns in deck mounts
on side, evenly spread
Weight of broadside 37 lbs / 17 kg
Shells per gun, main battery: 180
3 - 21.0" / 533 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.79" / 20 mm 0.20" / 5 mm -
2nd: 0.79" / 20 mm - -
3rd: 0.39" / 10 mm - -

- Conning tower: 0.98" / 25 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 12,882 shp / 9,610 Kw = 27.00 kts
Range 7,000nm at 15.00 kts
Bunker at max displacement = 384 tons

Complement:
77 - 101

Cost:
£0.314 million / $1.258 million

Distribution of weights at normal displacement:
Armament: 5 tons, 0.5 %
Armour: 4 tons, 0.4 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 2 tons, 0.2 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 2 tons, 0.2 %
Machinery: 382 tons, 45.2 %
Hull, fittings & equipment: 170 tons, 20.1 %
Fuel, ammunition & stores: 234 tons, 27.8 %
Miscellaneous weights: 50 tons, 5.9 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
227 lbs / 103 Kg = 7.4 x 3.9 " / 100 mm shells or 0.2 torpedoes
Stability (Unstable if below 1.00): 1.21
Metacentric height 0.9 ft / 0.3 m
Roll period: 11.0 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.07
Seaboat quality (Average = 1.00): 1.00

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.420
Length to Beam Ratio: 10.32 : 1
'Natural speed' for length: 15.84 kts
Power going to wave formation at top speed: 65 %
Trim (Max stability = 0, Max steadiness = 100): 70
Bow angle (Positive = bow angles forward): 30.00 degrees
Stern overhang: 6.56 ft / 2.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 16.24 ft / 4.95 m
- Forecastle (25 %): 9.84 ft / 3.00 m
- Mid (50 %): 8.86 ft / 2.70 m
- Quarterdeck (15 %): 8.86 ft / 2.70 m
- Stern: 10.83 ft / 3.30 m
- Average freeboard: 10.01 ft / 3.05 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 156.9 %
- Above water (accommodation/working, high = better): 56.4 %
Waterplane Area: 3,804 Square feet or 353 Square metres
Displacement factor (Displacement / loading): 96 %
Structure weight / hull surface area: 22 lbs/sq ft or 106 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 1.54
- Overall: 0.55
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is cramped
Ship has slow, easy roll, a good, steady gun platform

Quoted

Originally posted by AdmKuznetsov
since they have torpedos:



G. VESSELS NOT SUBJECT TO LIMITATIONS IN NUMBER AND/OR TONNAGE

OUCH!!!! damn...I wanted to keep those three torpedo tubes on board...the main purpose of those ships is to give the navy a long-range merchant escort with great ASW and some good AA capability, but the torpedoes meant a good deal of disuasory force if a raider happens to appear...


Well, given that I must erase them, I've improved the performance of the ship in the other two departments: AA and Anti-ship guns. AA battery has increased by 30%, and I've put a third 125mm DP gun on her. Range has been increased too.

Z25, Dutch Destroyer ASW Escort laid down 1909 (Engine 1929)

Displacement:
1.078 t light; 1.156 t standard; 1.735 t normal; 2.199 t full load

Dimensions: Length overall / water x beam x draught
300,10 ft / 295,28 ft x 29,86 ft x 16,40 ft (normal load)
91,47 m / 90,00 m x 9,10 m x 5,00 m

Armament:
3 - 4,92" / 125 mm guns in single mounts, 59,59lbs / 27,03kg shells, 1929 Model
Dual purpose guns in deck mounts
on centreline ends, majority forward, 1 raised mount
12 - 1,57" / 40,0 mm guns (6x2 guns), 1,95lbs / 0,88kg shells, 1929 Model
Anti-aircraft guns in deck mounts
on side, all amidships
12 - 0,79" / 20,0 mm guns (6x2 guns), 0,24lbs / 0,11kg shells, 1929 Model
Anti-aircraft guns in deck mounts
on side, evenly spread
Weight of broadside 205 lbs / 93 kg
Shells per gun, main battery: 350

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0,79" / 20 mm 0,39" / 10 mm -
2nd: 0,39" / 10 mm - -
3rd: 0,39" / 10 mm - -

- Conning tower: 0,98" / 25 mm

Machinery:
Oil fired boilers, steam turbines,
Direct drive, 2 shafts, 11.655 shp / 8.695 Kw = 24,00 kts
Range 12.500nm at 15,00 kts
Bunker at max displacement = 1.043 tons

Complement:
133 - 174

Cost:
£0,109 million / $0,437 million

Distribution of weights at normal displacement:
Armament: 26 tons, 1,5 %
Armour: 11 tons, 0,6 %
- Belts: 0 tons, 0,0 %
- Torpedo bulkhead: 0 tons, 0,0 %
- Armament: 8 tons, 0,5 %
- Armour Deck: 0 tons, 0,0 %
- Conning Tower: 3 tons, 0,2 %
Machinery: 358 tons, 20,6 %
Hull, fittings & equipment: 483 tons, 27,8 %
Fuel, ammunition & stores: 658 tons, 37,9 %
Miscellaneous weights: 200 tons, 11,5 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1.789 lbs / 812 Kg = 30,0 x 4,9 " / 125 mm shells or 0,7 torpedoes
Stability (Unstable if below 1.00): 1,19
Metacentric height 1,1 ft / 0,3 m
Roll period: 11,8 seconds
Steadiness - As gun platform (Average = 50 %): 72 %
- Recoil effect (Restricted arc if above 1.00): 0,25
Seaboat quality (Average = 1.00): 1,52

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0,420
Length to Beam Ratio: 9,89 : 1
'Natural speed' for length: 17,18 kts
Power going to wave formation at top speed: 55 %
Trim (Max stability = 0, Max steadiness = 100): 47
Bow angle (Positive = bow angles forward): 10,00 degrees
Stern overhang: 1,64 ft / 0,50 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 18,04 ft / 5,50 m
- Forecastle (20 %): 11,48 ft / 3,50 m
- Mid (55 %): 11,48 ft / 3,50 m
- Quarterdeck (15 %): 11,48 ft / 3,50 m
- Stern: 11,48 ft / 3,50 m
- Average freeboard: 12,01 ft / 3,66 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 92,9 %
- Above water (accommodation/working, high = better): 90,4 %
Waterplane Area: 5.496 Square feet or 511 Square metres
Displacement factor (Displacement / loading): 153 %
Structure weight / hull surface area: 42 lbs/sq ft or 203 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,76
- Longitudinal: 2,58
- Overall: 0,86
Hull space for machinery, storage, compartmentation is adequate
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

I wonder if those hulls are worth the money.....?!

Small ships tend to suffer from stress more than large hulls. Given that these ships are about 20 years old I wonder if the aren´t worn out. Even if you install new machinery their hulls simply may be too weak today....

I wouldn´t spend the time and money.

Well, for their planned main mission (long range ASW escorts with some degree of AA and ASuW) I think they are worth it.

They're old, yes, but in their new mission with the new machinery their hulls won't be particulary stressed by high speeds (24 knots) or heavy broadsides (3x125mm guns).

During WW2 V&W class destroyers gave a great account of themselfs on anti-submarine work, and by 1940 they were much older than what the Z25 is now.


Also, 18 new ASW escorts of this class would have a higher cost both in materials and in construction times than updating the old hulls at a time when the dutch industry is about to go through some work-intensive times (building the new Ijselijks, updating the ZPs or build two new slow BBs, an increase in the submarine force, etc etc etc)...so I really think the idea it's worth it

Ocean-going ASW escorts - that means a lot of sea-time in rough weather. And it´s not their new speed that caused stress - it´s their old life that did.

I also think comparing them to the V&Ws is not correct as the british units would never had such long life´s without a war going on.

We have no upkeep system for WesWorld (which is a good thing, methinks, keeping things easy) but I would expect those old units to cause more maintenance or personal costs than modern units. So from a roleplaying point of view I still wonder if their rebuild is a good idea...

as I said before, is all a matter or time and resources. To put it shortly, the time and resources I save by rebuilding those ships along those lines are time and resources I really need for other projects...Dutch infrastructure and industrial capability is pretty good for a middle power as Netherlands is, but there are just so many things I can do at the same time with them .

Also, the fleet really needs some more long-range ASW escorts so build a new class of ships at a latter date isn't a good idea either. I have eighteen destroyers that are going to the scrapyard, but which can be modified to cover that particular need for some time with a lesser cost than building a new class of the same numbers.

There's another thing, too. When more modern units of similar purpose are built (eventually they will be when times and resources allow for it), this ships will provide the fleet with a good base of training crews on ASW, while being a valuable reserve to put in active service again, in case of a war.


As it is now, the Dutch Navy is about to go into a period of intensive update and replacement of old ships with new ones. Until that period is over, this class is everything I can provide my fleet with on ocean-going ASW role.



BTW, the V&W were old and had issues, but certainly they got their job really well done, and were still in service by 1945, at at time when there were a lot of escorts, more than which were actually needed. They got the job done and did it successfully at a time when ASW escorts were badly needed.

My fleet badly needs a class of large far-reaching ASW escorts (so far the only dedicated ships with that role are the badly outdated F.1 class of frigates) , and while I'm not pressed by a war and so its not an emergency, I also am limited by being able of doing so many things in a limited time so...the situation is more similar to the one UK faced than what you might think otherwise...

"What torpedoes? Those are....umm...refrigeration units...yeah refrigeration units for Colonial duty in South East Asia. What? I'm sensing you don't believe me...."

RAM - if you have the room for it, why not leave the torpedoes in and classify these as coastal defence ships? I think it's probably as valuable as the escort cruiser function most people use the tonnage for.

As for the age of the hulls - it's a matter of expediency. Hooman's point on maintenance is valid, but with your limited resources (and grouchy neighbour(s)), I think it's not a bad thing to try and get some more use out of these ships.