WesWorld

The warning flags for the design's poor seaboat qualities ought to be obvious. I would heed them and refine the design to improve its seakeeping - I think that there is more than enough stability there to trim the design in the right direction.

I agree that the ship is carrying more armor for its armament than it is worth.

If you could rework the design to make it slightly shorter, you could build it in a Type 0 slip; as it is, you would need a Type 0.5 - just sayin'

Those small SAE boats also aren;t the greatest seaboats, but I would definitely trim the boat until you get Steadiness up to 50 %. This is one thing that lowers the seaboat rating. You won't get it all the way up to 1.00, but you should be able to get it a bit better than it is now.

Geoje - Class, Chosen Frigate / Corvette laid down 1942

Displacement:
805 t light; 831 t standard; 901 t normal; 956 t full load

Dimensions: Length overall / water x beam x draught
235,30 ft / 225,39 ft x 29,86 ft x 11,15 ft (normal load)
71,72 m / 68,70 m x 9,10 m x 3,40 m

Armament:
4 - 2,99" / 76,0 mm guns (2x2 guns), 13,39lbs / 6,07kg shells, 1942 Model
Dual purpose guns in deck mounts
on centreline ends, evenly spread
2 - 0,50" / 12,7 mm guns in single mounts, 0,06lbs / 0,03kg shells, 1942 Model
Machine guns in deck mounts
on side, all amidships
4 - 0,79" / 20,0 mm guns (1x4 guns), 0,24lbs / 0,11kg shells, 1942 Model
Anti-aircraft guns in deck mount
on centreline aft, all raised guns - superfiring
8 - 0,79" / 20,0 mm guns (2x4 guns), 0,24lbs / 0,11kg shells, 1942 Model
Anti-aircraft guns in deck mounts
on side, evenly spread
Weight of broadside 57 lbs / 26 kg
Shells per gun, main battery: 250
4 - 21,0" / 533 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1,38" / 35 mm 0,59" / 15 mm -
2nd: 0,39" / 10 mm 0,39" / 10 mm -
3rd: 0,39" / 10 mm 0,39" / 10 mm -

- Conning tower: 1,57" / 40 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 21.127 shp / 15.761 Kw = 30,80 kts
Range 4.500nm at 12,00 kts
Bunker at max displacement = 125 tons

Complement:
81 - 106

Cost:
£0,600 million / $2,402 million

Distribution of weights at normal displacement:
Armament: 7 tons, 0,8%
Armour: 10 tons, 1,1%
- Belts: 0 tons, 0,0%
- Torpedo bulkhead: 0 tons, 0,0%
- Armament: 7 tons, 0,7%
- Armour Deck: 0 tons, 0,0%
- Conning Tower: 3 tons, 0,4%
Machinery: 430 tons, 47,8%
Hull, fittings & equipment: 308 tons, 34,2%
Fuel, ammunition & stores: 96 tons, 10,6%
Miscellaneous weights: 50 tons, 5,6%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
364 lbs / 165 Kg = 27,2 x 3,0 " / 76 mm shells or 0,3 torpedoes
Stability (Unstable if below 1.00): 1,17
Metacentric height 1,1 ft / 0,3 m
Roll period: 12,0 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0,09
Seaboat quality (Average = 1.00): 0,90

Hull form characteristics:
Hull has raised forecastle, rise forward of midbreak, low quarterdeck
and transom stern
Block coefficient: 0,420
Length to Beam Ratio: 7,55 : 1
'Natural speed' for length: 17,75 kts
Power going to wave formation at top speed: 77 %
Trim (Max stability = 0, Max steadiness = 100): 55
Bow angle (Positive = bow angles forward): 20,00 degrees
Stern overhang: 2,62 ft / 0,80 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 20,01 ft / 6,10 m
- Forecastle (20%): 18,37 ft / 5,60 m (17,39 ft / 5,30 m aft of break)
- Mid (50%): 15,75 ft / 4,80 m (14,76 ft / 4,50 m aft of break)
- Quarterdeck (15%): 13,12 ft / 4,00 m (13,78 ft / 4,20 m before break)
- Stern: 13,12 ft / 4,00 m
- Average freeboard: 15,74 ft / 4,80 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 166,8%
- Above water (accommodation/working, high = better): 92,8%
Waterplane Area: 4.355 Square feet or 405 Square metres
Displacement factor (Displacement / loading): 74%
Structure weight / hull surface area: 30 lbs/sq ft or 148 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,51
- Longitudinal: 7,42
- Overall: 0,67
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate
Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

A little toned down for armament, but it's got the essentials.

Enter ship name, Enter country Enter ship type laid down 1942

Displacement:
715 t light; 737 t standard; 795 t normal; 842 t full load

Dimensions: Length overall / water x beam x draught
239.82 ft / 229.49 ft x 26.25 ft x 10.50 ft (normal load)
73.10 m / 69.95 m x 8.00 m x 3.20 m

Armament:
2 - 3.00" / 76.2 mm guns in single mounts, 13.50lbs / 6.12kg shells, 1942 Model
Dual purpose guns in deck mounts
on centreline ends, evenly spread
8 - 0.79" / 20.0 mm guns (2x4 guns), 0.24lbs / 0.11kg shells, 1942 Model
Machine guns in deck mounts
on centreline ends, evenly spread, all raised mounts
2 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1942 Model
Machine guns in deck mounts
on side, evenly spread
Weight of broadside 29 lbs / 13 kg
Shells per gun, main battery: 350
4 - 21.0" / 533 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: 0.79" / 20 mm 0.39" / 10 mm -
4th: 0.39" / 10 mm - -

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 19,210 shp / 14,330 Kw = 30.70 kts
Range 4,000nm at 12.00 kts
Bunker at max displacement = 105 tons

Complement:
74 - 97

Cost:
£0.522 million / $2.088 million

Distribution of weights at normal displacement:
Armament: 4 tons, 0.5 %
Armour: 5 tons, 0.6 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 5 tons, 0.6 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 386 tons, 48.5 %
Hull, fittings & equipment: 270 tons, 34.0 %
Fuel, ammunition & stores: 80 tons, 10.1 %
Miscellaneous weights: 50 tons, 6.3 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
306 lbs / 139 Kg = 22.7 x 3.0 " / 76 mm shells or 0.2 torpedoes
Stability (Unstable if below 1.00): 1.16
Metacentric height 0.9 ft / 0.3 m
Roll period: 11.7 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- 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
and transom stern
Block coefficient: 0.440
Length to Beam Ratio: 8.74 : 1
'Natural speed' for length: 17.62 kts
Power going to wave formation at top speed: 75 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 20.00 degrees
Stern overhang: 3.28 ft / 1.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 19.36 ft / 5.90 m
- Forecastle (20 %): 14.44 ft / 4.40 m
- Mid (50 %): 14.44 ft / 4.40 m
- Quarterdeck (15 %): 14.44 ft / 4.40 m
- Stern: 14.44 ft / 4.40 m
- Average freeboard: 14.83 ft / 4.52 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 167.5 %
- Above water (accommodation/working, high = better): 79.9 %
Waterplane Area: 3,958 Square feet or 368 Square metres
Displacement factor (Displacement / loading): 73 %
Structure weight / hull surface area: 27 lbs/sq ft or 133 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.51
- Longitudinal: 6.96
- Overall: 0.66
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is cramped

This is certainly a better seaboat. If its job is to escort, the armament is fine; but the customer seems to be looking for more of a hunter - which on such a small hull is difficult. Perhaps a rethink of roles is in order.

Quoted

Originally posted by Rooijen10
Those small SAE boats also aren;t the greatest seaboats.

Well, yes. Rated against WW standard where ships usually have a seaboat rating of 1,00+ you are right. However, for quite some time I wonder if this is correct. Historically vessels of that size weren't great seaboats, and they suffered from heavy seas (reduced speed, heavy rolling and pitching, lots of water over their bows, crews wet to the bone etc.). One just has to read some WW2 reports from escorts or destroyers operating in the North Atlantic/North Sea/Biscaya.

All that SS offers for a sea boat rating below 1.00 is "Poor seaboat, wet and uncomfortable, reduced performance in heavy weather" - which seems perfectly in line with historical reports for such vessels.

Reading from those reports I even dare say DD must not have a seaboat rating of 1.00. In fact, some WW DD designs have a freeboard well above what was historical standard. Part of this comes from SS calculations where speed plays an important role of course.

What do you think?

[URL=http://www.navalism.org/index.php/topic,4588.0.html]This thread[/URL] over on the Navalism board might be of some interest for this topic.

Destroyers should also be capable of higher speeds with lower machinery weights, and SS doesn't handle that well, either. Nor does it provide adequate weights for torpedoes. Nor intermediate caliber batteries (4"-6"), or semi-planing hulls. It doesn't give us options for aircraft. Nor lots of other stuff. I think it's just one of the limitations of the tool we're using, I feel.

I intentionally try to design my destroyers to be better seaboats than everyone else's, in any case.

I look upon the seaboat quality rating as a parameter subject to the player's discretion. I certainly would not accept a ukase that ship class A cannot have a seaboat quality rating exceeding value X.

Historically, destroyers of First World War vintage were comparatively poor seaboats - their designers loading more weapons on a small platform with demands for high speeds. If a player wishes to replicate such designs, so be it - the result is a small overloaded vessel. If a player wishes to build a larger vessel that handles high seas well that too is acceptable.

Quoted

Originally posted by snip
[URL=http://www.navalism.org/index.php/topic,4588.0.html]This thread[/URL] over on the Navalism board might be of some interest for this topic.

It does. Thanks for sharing...

deck armor : there were USN DD classes with 0.5" deck armor, reportedly as an anti-strafing measure (and splinters?)

Seakeeping : as far as I view things, poor seakeeping means it's going to slow down and be unfightable in heavy seas more rapidly than the same vessel with average or better seakeeping. With the "cramped" crew conditions, the crew would rapidly become tired and worn out. As long as the design parameters accept those limitations, I don't see why not.

For my part, I've been designing escorts/DDs to 1.2 of late, both for the long open-ocean voyages, and for long range AA/AS accuracy, to take advantage of Radar's accurate ranging data.

thread : I remember that I still like my suggestion to add 0.4 to the seakeeping of sims to compensate.

I've had the same thoughts as Hoo on occasion, and mentioned it at times; Not every design is a winner, and a lot of perfectly servicable and long-serving historical ships were known as not-the-best seaboats.

That being said, since I run a nation with operating needs in areas known for particularly bad weather, all my designs have trended to the high seakeeping requirements.

I read the thread snip posted and if I consider their arguments I don't think a seaboat quality less then 1,0 would be a problem for my corvette. It's intended role is more that of an enlarged motor torpedo boat so it would mostly be at sea for a few days in areas which are not too far away from the coast (Yellow Sea, area around Jeju-Do). Therefore the boat doesn't need to be typhoon resistant or super comfortable for the crew.
Thanks for the comments and the input so far, it was a great help to me.

Quoted

Originally posted by parador
Hull has raised forecastle, rise forward of midbreak, low quarterdeck

By-the-by, is this an intentional design element? Having a break at every point seems a bit odd.

Could be an error. The steps are rather small, though maybe he had something sinister in mind with that.

Quoted

Freeboard (% = measuring location as a percentage of overall length): - Stem: 20,01 ft / 6,10 m - Forecastle (20%): 18,37 ft / 5,60 m (17,39 ft / 5,30 m aft of break) - Mid (50%): 15,75 ft / 4,80 m (14,76 ft / 4,50 m aft of break) - Quarterdeck (15%): 13,12 ft / 4,00 m (13,78 ft / 4,20 m before break) - Stern: 13,12 ft / 4,00 m - Average freeboard: 15,74 ft / 4,80 m

First step is 30cm, the second one is 30cm as well and the last one is 20cm.