WesWorld

Auxiliaries of the MIBN

Almirante Gastão Motta class replenishment ship
- MIBN Almirante Gastão Motta
- MIBN Almirante Guilhem

Almirante Gastão Motta, Brazilian Underway Replenishment Ship laid down 1943

Displacement:
6,120 t light; 6,492 t standard; 17,915 t normal; 27,052 t full load

Dimensions: Length overall / water x beam x draught
536.01 ft / 524.93 ft x 63.65 ft x 28.87 ft (normal load)
163.38 m / 160.00 m x 19.40 m x 8.80 m

Armament:
4 - 1.46" / 37.0 mm guns (2x2 guns), 1.55lbs / 0.70kg shells, 1943 Model
Anti-aircraft guns in deck mounts
on centreline ends, evenly spread
4 - 0.79" / 20.0 mm guns (2x2 guns), 0.24lbs / 0.11kg shells, 1943 Model
Machine guns in deck mounts
on side, all amidships
Weight of broadside 7 lbs / 3 kg
Shells per gun, main battery: 3,000

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 1 shaft, 7,654 shp / 5,710 Kw = 15.00 kts
Range 124,500nm at 12.00 kts
Bunker at max displacement = 20,560 tons

Complement:
773 - 1,006

Cost:
£1.588 million / $6.352 million

Distribution of weights at normal displacement:
Armament: 1 tons, 0.0 %
Machinery: 198 tons, 1.1 %
Hull, fittings & equipment: 3,421 tons, 19.1 %
Fuel, ammunition & stores: 11,795 tons, 65.8 %
Miscellaneous weights: 2,500 tons, 14.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
79,598 lbs / 36,105 Kg = 51,502.6 x 1.5 " / 37 mm shells or 11.8 torpedoes
Stability (Unstable if below 1.00): 1.44
Metacentric height 4.8 ft / 1.5 m
Roll period: 12.2 seconds
Steadiness - As gun platform (Average = 50 %): 75 %
- Recoil effect (Restricted arc if above 1.00): 0.00
Seaboat quality (Average = 1.00): 1.79

Hull form characteristics:
Hull has raised forecastle, raised quarterdeck
Block coefficient: 0.650
Length to Beam Ratio: 8.25 : 1
'Natural speed' for length: 22.91 kts
Power going to wave formation at top speed: 28 %
Trim (Max stability = 0, Max steadiness = 100): 42
Bow angle (Positive = bow angles forward): 10.00 degrees
Stern overhang: 6.56 ft / 2.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 25.59 ft / 7.80 m
- Forecastle (15 %): 24.93 ft / 7.60 m (13.12 ft / 4.00 m aft of break)
- Mid (50 %): 13.12 ft / 4.00 m
- Quarterdeck (25 %): 22.31 ft / 6.80 m (13.12 ft / 4.00 m before break)
- Stern: 22.97 ft / 7.00 m
- Average freeboard: 17.31 ft / 5.28 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 20.6 %
- Above water (accommodation/working, high = better): 81.6 %
Waterplane Area: 25,236 Square feet or 2,345 Square metres
Displacement factor (Displacement / loading): 617 %
Structure weight / hull surface area: 84 lbs/sq ft or 412 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.97
- Longitudinal: 1.26
- Overall: 1.00
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is cramped
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

Ships in Class:
- MIBN Almirante Gastão Motta
- MIBN Almirante Guilhem

Pernambuco, Brazil Hydrographic Survey Ship laid down 1947

Displacement:
1,315 t light; 1,349 t standard; 1,555 t normal; 1,720 t full load

Dimensions: Length overall / water x beam x draught
286.63 ft / 278.87 ft x 34.45 ft x 10.73 ft (normal load)
87.37 m / 85.00 m x 10.50 m x 3.27 m

Armament:
1 - 3.00" / 76.2 mm guns in single mounts, 13.50lbs / 6.12kg shells, 1947 Model
Anti-aircraft gun in deck mount
on centreline forward
4 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1947 Model
Anti-aircraft guns in deck mounts
on side ends, evenly spread, all raised mounts - superfiring
Weight of broadside 14 lbs / 7 kg
Shells per gun, main battery: 250

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 24,000 shp / 17,904 Kw = 28.20 kts
Range 9,500nm at 12.00 kts
Bunker at max displacement = 371 tons

Complement:
123 - 160

Cost:
£0.950 million / $3.798 million

Distribution of weights at normal displacement:
Armament: 2 tons, 0.1 %
Machinery: 593 tons, 38.1 %
Hull, fittings & equipment: 401 tons, 25.8 %
Fuel, ammunition & stores: 239 tons, 15.4 %
Miscellaneous weights: 320 tons, 20.6 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
735 lbs / 333 Kg = 54.4 x 3.0 " / 76 mm shells or 0.4 torpedoes
Stability (Unstable if below 1.00): 1.20
Metacentric height 1.4 ft / 0.4 m
Roll period: 12.2 seconds
Steadiness - As gun platform (Average = 50 %): 51 %
- Recoil effect (Restricted arc if above 1.00): 0.01
Seaboat quality (Average = 1.00): 1.15

Hull form characteristics:
Hull has low quarterdeck
Block coefficient: 0.528
Length to Beam Ratio: 8.10 : 1
'Natural speed' for length: 16.70 kts
Power going to wave formation at top speed: 71 %
Trim (Max stability = 0, Max steadiness = 100): 44
Bow angle (Positive = bow angles forward): 20.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 21.33 ft / 6.50 m
- Forecastle (20 %): 18.04 ft / 5.50 m
- Mid (50 %): 16.90 ft / 5.15 m
- Quarterdeck (15 %): 9.84 ft / 3.00 m (16.90 ft / 5.15 m before break)
- Stern: 9.84 ft / 3.00 m
- Average freeboard: 16.50 ft / 5.03 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 146.7 %
- Above water (accommodation/working, high = better): 174.6 %
Waterplane Area: 6,568 Square feet or 610 Square metres
Displacement factor (Displacement / loading): 102 %
Structure weight / hull surface area: 30 lbs/sq ft or 146 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 3.34
- Overall: 0.60
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is excellent

Misc Weight
5 tons for surface search RDF set
20 tons for ASDIC and twin echo sounders
25 tons for crane and deck handling gear
120 tons for marine laboratories
50 tons for accommodation for 25 scientists
50 tons for improved habitability
50 tons for growth

MIBN Pernambuco: completed 1947