Something a lot different;
An Oceanic Tug/Repair ship. The Meditterenean is becoming increasingly crowded with larger and larger ships (merchant as well as naval units). The current largest tugs are approx 500tons shown
here. This vessel(s) is considerably larger with more power. This makes it more suitable for towing larger vessels. In its secondary role, it'll serve as a repair ship, having materials onboard for effecting temporary repairs.
The design itself is heavily built with extensive subdivision inboard and thicker than usual outer hull plates (in addition to fenders). There are extensive accomodations onboard in case crew need to be taken off.
Machinery includes 2x2000hp marine diesels from the Gabbiano class of escorts. In addition to this are 2x5000hp Fiat-Guidoni diesels with clutches that can be engaged to the propellor shafts to transmit additional power if needed.
Tug/Repair ship, laid down 1935
Displacement:
1,899 t light; 1,966 t standard; 2,656 t normal; 3,208 t full load
Dimensions: Length overall / water x beam x draught
304.05 ft / 295.28 ft x 49.21 ft x 9.84 ft (normal load)
92.68 m / 90.00 m x 15.00 m x 3.00 m
Armament:
4 - 0.98" / 25.0 mm guns (2x2 guns), 0.55lbs / 0.25kg shells, 1935 Model
Anti-aircraft guns in deck mounts
on side, all forward
4 - 1.85" / 47.0 mm guns (1x4 guns), 3.86lbs / 1.75kg shells, 1935 Model
Anti-aircraft guns in deck mount
on centreline aft
Weight of broadside 18 lbs / 8 kg
Shells per gun, main battery: 1,000
Armour:
- Belts: Width (max) Length (avg) Height (avg)
Ends: Unarmoured
- Torpedo Bulkhead:
0.39" / 10 mm 213.25 ft / 65.00 m 16.40 ft / 5.00 m
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
2nd: 0.39" / 10 mm 0.39" / 10 mm -
Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 4,000 shp / 2,984 Kw = 17.00 kts
Range 10,440nm at 16.00 kts
Bunker at max displacement = 1,242 tons
Complement:
184 - 240
Cost:
£0.427 million / $1.708 million
Distribution of weights at normal displacement:
Armament: 2 tons, 0.1 %
Armour: 52 tons, 2.0 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 51 tons, 1.9 %
- Armament: 1 tons, 0.0 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 114 tons, 4.3 %
Hull, fittings & equipment: 1,181 tons, 44.5 %
Fuel, ammunition & stores: 758 tons, 28.5 %
Miscellaneous weights: 550 tons, 20.7 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
13,437 lbs / 6,095 Kg = 28,185.2 x 1.0 " / 25 mm shells or 4.0 torpedoes
Stability (Unstable if below 1.00): 1.10
Metacentric height 2.1 ft / 0.6 m
Roll period: 14.3 seconds
Steadiness - As gun platform (Average = 50 %): 94 %
- Recoil effect (Restricted arc if above 1.00): 0.01
Seaboat quality (Average = 1.00): 2.00
Hull form characteristics:
Hull has rise forward of midbreak
and transom stern
Block coefficient: 0.650
Length to Beam Ratio: 6.00 : 1
'Natural speed' for length: 20.13 kts
Power going to wave formation at top speed: 49 %
Trim (Max stability = 0, Max steadiness = 100): 47
Bow angle (Positive = bow angles forward): 10.00 degrees
Stern overhang: 3.28 ft / 1.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 31.17 ft / 9.50 m
- Forecastle (20 %): 26.25 ft / 8.00 m
- Mid (60 %): 24.61 ft / 7.50 m (16.40 ft / 5.00 m aft of break)
- Quarterdeck (15 %): 16.40 ft / 5.00 m
- Stern: 16.40 ft / 5.00 m
- Average freeboard: 22.38 ft / 6.82 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 65.5 %
- Above water (accommodation/working, high = better): 264.0 %
Waterplane Area: 11,614 Square feet or 1,079 Square metres
Displacement factor (Displacement / loading): 315 %
Structure weight / hull surface area: 60 lbs/sq ft or 293 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.89
- Longitudinal: 7.06
- Overall: 1.10
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable, can fire her guns in the heaviest weather
5000miles at 80% power = 337tons main engines
2x5000hp Fiat-Guidoni Diesels + auxiliaries = 100tons
5000miles at 80% power = 1.6tons/hour
Speed with both engines at 80% = 22.6knts
Time to cover 5000nm=221hrs = 353tons fuel for Fiat diesels
Total fuel = 337+353 = 690tons
450tons = supplies/cranes/gensets etc.
Built to 1.10hull strength with thicker hull plates.