WesWorld

One I missed...


MS-5 Arethousa Class Minesweeper,
Greece MS laid down 1925


These ships are reciprocal engined as all turbine production is going to the Escort Program.

They will replace old torpedo boats converted to minesweepers. These old ships Kharybdis, Harpie, Minotaur and Phoinix, currently in reserve, will be expended as targets.

Displacement:
801 t light; 823 t standard; 940 t normal; 1,034 t full load

Dimensions: Length overall / water x beam x draught
247.75 ft / 245.00 ft x 24.60 ft x 10.30 ft (normal load)
75.51 m / 74.68 m x 7.50 m x 3.14 m

Armament:
2 - 4.00" / 102 mm guns in single mounts, 32.00lbs / 14.51kg shells, 1925 Model
Breech loading guns in deck mounts
on centreline ends, evenly spread, all raised mounts
4 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1925 Model
Breech loading guns in deck mounts
on side, all amidships, all raised mounts - superfiring
Weight of broadside 64 lbs / 29 kg
Shells per gun, main battery: 80

Machinery:
Oil fired boilers, complex reciprocating steam engines,
Direct drive, 2 shafts, 4,275 ihp / 3,189 Kw = 20.00 kts
Range 4,500nm at 12.00 kts (Bunkerage = 210 tons)

Complement:
84 - 110

Cost:
£0.227 million / $0.908 million

Distribution of weights at normal displacement:
Armament: 8 tons, 0.9 %
Machinery: 247 tons, 26.2 %
Hull, fittings & equipment: 422 tons, 44.9 %
Fuel, ammunition & stores: 139 tons, 14.7 %
Miscellaneous weights: 125 tons, 13.3 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1,275 lbs / 578 Kg = 39.9 x 4.0 " / 102 mm shells or 0.5 torpedoes
Stability (Unstable if below 1.00): 1.06
Metacentric height 0.7 ft / 0.2 m
Roll period: 12.5 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.27
Seaboat quality (Average = 1.00): 2.00

Hull form characteristics:
Hull has raised forecastle, rise forward of midbreak
Block coefficient: 0.530
Length to Beam Ratio: 9.96 : 1
'Natural speed' for length: 15.65 kts
Power going to wave formation at top speed: 54 %
Trim (Max stability = 0, Max steadiness = 100): 25
Bow angle (Positive = bow angles forward): 5.00 degrees
Stern overhang: 1.00 ft / 0.30 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 20.00 ft / 6.10 m
- Forecastle (20 %): 19.00 ft / 5.79 m (18.00 ft / 5.49 m aft of break)
- Mid (70 %): 18.00 ft / 5.49 m (10.00 ft / 3.05 m aft of break)
- Quarterdeck (10 %): 10.00 ft / 3.05 m
- Stern: 10.00 ft / 3.05 m
- Average freeboard: 15.88 ft / 4.84 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 106.2 %
- Above water (accommodation/working, high = better): 147.1 %
Waterplane Area: 4,128 Square feet or 384 Square metres
Displacement factor (Displacement / loading): 138 %
Structure weight / hull surface area: 35 lbs/sq ft or 173 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.77
- Longitudinal: 10.65
- Overall: 1.00
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

Hey there, another of your nice drawings. :o)

I wonder about the number of light guns on the pic...? Doesn´t fit to what can be read in the SS-file.

Only 80 shells/gun? That´s hardly enough for even 10mins of sustained fire...

Why such a high l:b ratio for a vessel which should be capable of tight manovers at low speed (while minesweeping)?

Why are there no buckles amidship?

The fire arcs of the light guns amidship seems somewhat limited. Ever thought about putting the guns on a raised platform (~1,5m might be enough)?

Just my monday morning rant... ;o)

HoOmAn

Quoted

These ships are reciprocal engined as all turbine production is going to the Escort Program.

I guess Greece has yet to discover the wonders of diesel...

Well, coal burners have a nice side effect - they don´t put strain on ones (oil) fuel supply....

Quoted

Well, coal burners have a nice side effect - they don´t put strain on ones (oil) fuel supply....

True...but burners of "earl" put less strain on ones manpower supply. :-)

Besides:

Quoted

MS-5 Arethousa Class Minesweeper,
Greece MS laid down 1925

...

Machinery:
Oil fired boilers, complex reciprocating steam engines,

Ooops... /

Yep always putting to many guns on my pics.

80 rpg - bigger mag means bigger boom - these ships go into the minefield.

I'll add more portholes.

Diesels are for submarines and ferrys.

Cheers,

Quoted

Diesels are for submarines and ferrys.

With the M.A.N.O.¹ plant constructing, the Philippines begs to differ...

By 1940, if all goes well, I'll have 257² diesel-powered vessels in the Filipino fleet, plus two more with diesel auxilaries...

¹ - M.A.N. Ost. ^_^

² - including 150 ten-ton vedettes.

Quoted

Originally posted by alt_naval
80 rpg - bigger mag means bigger boom - these ships go into the minefield.

*cough cough*

Does it really matter? I mean - if such a ship really hits a mine it will be gone anyway.... Further more there weren´t many mine hits setting off magazins historically. If the mag chamber is breeched water rushing in tends to prevent an explosion...

Quoted

Further more there weren´t many mine hits setting off magazins historically

Purpose built WW1 RN mineweepers (can't recall which ones) had box magazines aft that on occasions had been blown out of the ship after a mine detonation (I don't know if it was necessary for the ship to actually hit the mine).

Cheers,