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Tuesday, August 13th 2019, 9:21pm

naval projects for Atlantis, 1948

In 1948 Atlantis decided to convert its little used Airship tenders into missile test ships, renaming them for prominent stars in constellations.

Polaris (ex-Lamia) Regulus (ex-Tronagarru), Atlantean Missile test ship laid down 1925

Displacement:
10,166 t light; 10,414 t standard; 12,417 t normal; 14,019 t full load

Dimensions: Length overall / water x beam x draught
446.88 ft / 435.00 ft x 65.62 ft x 26.25 ft (normal load)
136.21 m / 132.59 m x 20.00 m x 8.00 m

Machinery:
Oil fired boilers, complex reciprocating steam engines,
Geared drive, 2 shafts, 20,107 ihp / 15,000 Kw = 20.54 kts
Range 10,000nm at 15.00 kts
Bunker at max displacement = 3,606 tons

Complement:
587 - 764

Cost:
£1.696 million / $6.785 million

Distribution of weights at normal displacement:
Armament: 0 tons, 0.0 %
Machinery: 1,161 tons, 9.3 %
Hull, fittings & equipment: 4,005 tons, 32.3 %
Fuel, ammunition & stores: 2,251 tons, 18.1 %
Miscellaneous weights: 5,000 tons, 40.3 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
14,432 lbs / 6,546 Kg = 133.6 x 6 " / 152 mm shells or 2.2 torpedoes
Stability (Unstable if below 1.00): 1.01
Metacentric height 2.7 ft / 0.8 m
Roll period: 16.8 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.00
Seaboat quality (Average = 1.00): 1.46

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.580
Length to Beam Ratio: 6.63 : 1
'Natural speed' for length: 20.86 kts
Power going to wave formation at top speed: 50 %
Trim (Max stability = 0, Max steadiness = 100): 34
Bow angle (Positive = bow angles forward): 10.00 degrees
Stern overhang: 8.00 ft / 2.44 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 22.00 ft / 6.71 m
- Forecastle (20 %): 15.50 ft / 4.72 m
- Mid (50 %): 15.50 ft / 4.72 m
- Quarterdeck (15 %): 15.50 ft / 4.72 m
- Stern: 15.50 ft / 4.72 m
- Average freeboard: 16.02 ft / 4.88 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 74.8 %
- Above water (accommodation/working, high = better): 103.1 %
Waterplane Area: 20,490 Square feet or 1,904 Square metres
Displacement factor (Displacement / loading): 170 %
Structure weight / hull surface area: 127 lbs/sq ft or 622 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.44
- Longitudinal: 2.59
- Overall: 1.52
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is adequate
Good seaboat, rides out heavy weather easily

Notes: The Polaris (ex-Lamia) and Regulus (ex-Tronagarru) were taken in had for convertion in 1948 to missile test ships. This involved removal of all airship tending equipment and the airship mast. The aviation fuel tank area was also modified to carry the various propellants needed to fuel the test missiles. A hagar was built aft to house the test stands, missile handling equipment and assembled missiles, the old funnel being trunked into two separate funnels at the sides of the hangar. Forward of the hangar was the missile assembly area and workshops.

Below the hangar and workshop the old airship spare parts storage was converted to store disassembled missiles. Additional space for crew, workshops, scientific labs, and generator rooms took up the remaining spaces in the new midships structure. A large mast was built on top of the midships structure forward of the hangar to mount tracking radar and the missile control platform sat at its base. A secondary control site sat on top of the after end of the hangar. Three heavy lift cranes were added aft to handle/errect the various test stands onto a 68'x68' 2" steel platform. Total cost for refit 2,546 tons.

Misc weight breakdown:
Missiles (varied) 10xAAM-5 missiles - 200 tons, 4xRapier cruise missiles 24 tons, 12xHera missiles - 12 tons, 10xDragon missiles 41 tons, 12xPhoenix missiles - 15 tons. Total capacity for 300 tons of missiles.
68'x68' 2" steel platform - 200 tons
Missile workshop - 1,000 tons
Launch stands for various missiles - 400 tons
Guidance and tracking radars - 50 tons
Navagational radar and other electronics - 20 tons
Three 50 ton cranes and Missile handling equipment - 350 tons
Science labs, crew amenities/berthing - 380 tons
Solid and Liquid fuel for missiles 900 tons
Missile control platform 200 tons
Total weight: 5,000 tons

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Wednesday, August 14th 2019, 9:52am

An ambitious rebuild but one that certainly makes good use out of an older obsolete ship class.
The only thing that I would comment on, and that is not surprising given the scale of the misc weight, is that the stability is borderline at 1.01. But I assume you intend using this in sheltered coastal waters so it would not be a massive handicap.

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Wednesday, August 14th 2019, 10:46am

You would be correct, these are test ships only and would be used in sheltered coastal waters in either northern Venezuela or Mauritania, most likely the former.