WesWorld

This particular class consists of three vessels, the Hydra Psara and Spetsai. These units were built in France by Forge et Chantiers de la Mediterranean who also plaid a major role in 1897 with the British firm Vickers in establishing the Greek ship building industry in Attica The Hydra class for a decade were the backbone of the Greek navy. Although they are now severely superseded two of these ships continue to serve the nation as training vessels, while the third has been converted into an accommodation hulk.

Those of you who are planning to demilitarise a ship and convert it into a training vessels will find the Spetsai of interest


Hydra class Central citadel Barbette.

Hydra
Laid down 24/1/1889
Lunched 19/8/1890
Commissioned 29/ 9/91
Modifications. 1901, sails and rigging removed power plant refurbished.
Current status. Once removal from active service in 1915 the Hydra was immediately converted into an accommodation hulk for Souda bay

Psara
Laid down 24/1/1889
Lunched 26/8/1890
Commissioned 23/ 10/91
Modifications. 1901, sails and rigging removed power plant refurbished. 1910 converted into gunnery training ship, on completion renamed Aries. For details of conversion see below under Aries.
Current status. Active.

Spetsai
Laid down 14/2/1890
Lunched 22/6/1891
Commissioned 27/ 7/92
Modifications. 1901, sails and rigging removed power plant refurbished. 1916, converted into cadet training ship, as part of modifications original armament removed and replaced with light guns. New power plant also installed, for details of conversion see below under Spetsai.
Current status. Active.



Hydra class as built 1889.

Length, 102.0 m x Beam, 15.8 m x Depth, 5.4 m
4825 tonnes normal displacement (4484 tonnes standard)

Barbette ship
Central citadel ship
Main battery: 1 x 27.5-cm (1 x 1)
Secondary battery: 2 x 27.5-cm
QF battery: 5 x 15.0-cm

Weight of broadside: 1084 kg

Main belt, 30.5 cm; bow and stern, 10.2 cm
Armor deck, average 2.5 cm

Battery armor:
Main, 35.6 cm
QF, 30.5 cm

Maximum speed for 2775 indicated kw = 15.00 knots
Approximate cruising radius, 3100 nm / 10 knots

Typical complement: 289-376


Estimated cost, $1.975 million (£494,000)

Remarks:

Relative extent of belt armor, 95 percent of 'typical' coverage.

Ship has slow, easy roll; a good, steady gun platform.

Good seaboat; rides out heavy weather easily.

Cramped ship; poor crew accommodation, limited working space.

Main deck QF guns subject to being washed down in a seaway.


Distribution of weights:
Percent
normal
displacement:

Armament ......................... 298 tonnes = 6 pct
Armor, total ..................... 1559 tonnes = 32 pct

Belt 1067 tonnes = 22 pct
Deck 215 tonnes = 4 pct
Armament 277 tonnes = 6 pct

Machinery ........................ 692 tonnes = 14 pct
Hull and fittings; equipment ..... 1640 tonnes = 34 pct
Fuel, ammunition, stores ......... 636 tonnes = 13 pct
Miscellaneous weights ............ 0 tonnes = 0 pct
-----
4825 tonnes = 100 pct

Estimated metacentric height, 0.9 m

Displacement summary:

Light ship: 4189 tonnes
Standard displacement: 4484 tonnes
Normal service: 4825 tonnes
Full load: 5078 tonnes

Loading submergence 1088 tonnes/metre

+++++++++++++++++++++++++


Estimated overall survivability and seakeeping ability:

Relative margin of stability: 1.33

Shellfire needed to sink: 2153 kg = 7.6 x 27.5-cm shells
(Approximates weight of penetrating
shell hits needed to sink ship,
not counting critical hits)

Torpedoes needed to sink: 1.1
(Approximates number of 'typical'
torpedo hits needed to sink ship)

Relative steadiness as gun platform, 71 percent
(50 percent is 'average')

Relative rocking effect from firing to beam, 0.52

Relative quality as a seaboat: 1.21

+++++++++++++++++++++++++


Hull form characteristics:

Block coefficient: 0.55
Sharpness coefficient: 0.40
Hull speed coefficient 'M' = 6.05
'Natural speed' for length = 18.3 knots
Power going to wave formation
at top speed: 38 percent


Estimated hull characteristics and strength:

Relative underwater volume absorbed by
magazines and engineering spaces: 94 percent

Relative accommodation and working space: 70 percent


Displacement factor: 89 percent
(Displacement relative to loading factors)


Relative cross-sectional hull strength: 0.97
(Structure weight per square
metre of hull surface: 482 kg)

Relative longitudinal hull strength: 1.37
(for 2.80 m average freeboard;
freeboard adjustment -1.19 m)

Relative composite hull strength: 1.00

+++++++++++++++++++++++++


[Machine-readable parameters: Spring Style v. 1.2.1]

334.56 x 51.82 x 17.71; 9.18 -- Dimensions
0.55 -- Block coefficient
1889 -- Year laid down
15.00 / 3100 / 10.00; Reciprocating -- Speed / radius / cruise
0 tons -- Miscellaneous weights
++++++++++
1 x 10.83; 1 -- Main battery; turrets
Central positioning of guns
Open barbettes
:
2 x 10.83; 0 -- Secondary battery; turrets
:
5 x 5.91 -- Tertiary (QF/AA) battery
Main deck battery
:
0 -- No fourth (light) battery
0 -- No torpedo armament
++++++++++
12.00 / 4.00 / 0.00 / 0.00; 95 -- Belt armor; relative extent
1.00 / 0.00 -- Deck / CT
14.00 / 0.00 / 12.00 / 0.00 -- Battery armor


(Note: For portability, values are stored in Anglo-American units)



Aries, gunnery training ship (former Psara)

In 1907 the Central citadel Barbette ship Psara was damage in a collision with a Beta class torpedo boat during a nigh time training exercise. With the commissioning of the final of three Pericles class cruiser a week before the accident and good progress being made with the construction of the Averoff, it was concluded that the Psara was redundant and no longer worth the cost of repairs. The ship was therefore decommissioned and placed in reserve where it remained for nearly three years, with only minor repairs made to prevent flooding.

During the 1910 spring manoeuvres it was found that fleet gunnery was abysmal. Two months later it was decided that a ship should be built specifically to act as a floating classroom for gunnery training. To save cost the decision to convert the redundant Psara was made. At the end of its conversion the ship received new guns, a new power plant and more importantly the quarterdeck was raised by 2.2meters to increase accommodation and provide the required classrooms. The changes completely transformed the ship’s appearance and only the idiosyncratic distribution of its armament betrayed it ancestry.

Aries 1910 rebuild

Length, 102.0 m x Beam, 15.8 m x Depth, 5.4 m
4825 tonnes normal displacement (4376 tonnes standard)

Main battery: 1 x 30.5-cm (1 x 1)
Secondary battery: 2 x 17.8-cm
QF battery: 4 x 14.0-cm
Light battery: 6 x 7.6-cm

Weight of broadside: 737 kg

6 TT, 45.7 cm (2 submerged)

Main belt, 30.5 cm; bow and stern, 10.2 cm
Armor deck, average 2.5 cm

Battery armor:
Main, 20.3 cm / secondary, 10.2 cm
QF, 20.3 cm

Maximum speed for 5460 shaft kw = 18.00 knots
Approximate cruising radius, 5800 nm / 10 knots

Typical complement: 289-376


Estimated cost, $1.447 million (£362,000)

Remarks:

Relative extent of belt armor, 95 percent of 'typical' coverage.

Ship has slow, easy roll; a good, steady gun platform.

Excellent seaboat; comfortable and able to fight her guns
in the heaviest weather.

Magazines and engineering spaces are roomy, with superior
watertight subdivision.

Main deck QF guns subject to being washed down in a seaway.


Distribution of weights:
Percent
normal
displacement:

Armament ......................... 203 tonnes = 4 pct
Armor, total ..................... 1642 tonnes = 34 pct

Belt 1067 tonnes = 22 pct
Deck 215 tonnes = 4 pct
Armament 360 tonnes = 7 pct

Machinery ........................ 333 tonnes = 7 pct
Hull and fittings; equipment ..... 1787 tonnes = 37 pct
Fuel, ammunition, stores ......... 681 tonnes = 14 pct
Miscellaneous weights ............ 180 tonnes = 4 pct
-----
4825 tonnes = 100 pct

Estimated metacentric height, 0.7 m

Displacement summary:

Light ship: 4144 tonnes
Standard displacement: 4376 tonnes
Normal service: 4825 tonnes
Full load: 5165 tonnes

Loading submergence 1088 tonnes/metre

+++++++++++++++++++++++++


Estimated overall survivability and seakeeping ability:

Relative margin of stability: 1.14

Shellfire needed to sink: 4028 kg = 10.3 x 30.5-cm shells
(Approximates weight of penetrating
shell hits needed to sink ship,
not counting critical hits)

Torpedoes needed to sink: 1.9
(Approximates number of 'typical'
torpedo hits needed to sink ship)

Relative steadiness as gun platform, 71 percent
(50 percent is 'average')

Relative rocking effect from firing to beam, 0.73

Relative quality as a seaboat: 1.82

+++++++++++++++++++++++++


Hull form characteristics:

Block coefficient: 0.55
Sharpness coefficient: 0.40
Hull speed coefficient 'M' = 6.05
'Natural speed' for length = 18.3 knots
Power going to wave formation
at top speed: 48 percent


Estimated hull characteristics and strength:

Relative underwater volume absorbed by
magazines and engineering spaces: 62 percent

Relative accommodation and working space: 111 percent


Displacement factor: 117 percent
(Displacement relative to loading factors)


Relative cross-sectional hull strength: 0.90
(Structure weight per square
metre of hull surface: 465 kg)

Relative longitudinal hull strength: 2.74
(for 5.00 m average freeboard;
freeboard adjustment +1.01 m)

Relative composite hull strength: 1.00

+++++++++++++++++++++++++


[Machine-readable parameters: Spring Style v. 1.2.1]

334.56 x 51.82 x 17.71; 16.40 -- Dimensions
0.55 -- Block coefficient
1910 -- Year laid down
18.00 / 5800 / 10.00; Turbine, coal fired -- Speed / radius / cruise
180 tons -- Miscellaneous weights
++++++++++
1 x 12.00; 1 -- Main battery; turrets
Central positioning of guns
:
2 x 7.00; 0 -- Secondary battery; turrets
:
4 x 5.50 -- Tertiary (QF/AA) battery
Main deck battery
:
6 x 3.00 -- Fourth (light) battery
6 / 2 / 18.00 -- TT / submerged / size
++++++++++
12.00 / 4.00 / 0.00 / 0.00; 95 -- Belt armor; relative extent
1.00 / 0.00 -- Deck / CT
8.00 / 4.00 / 8.00 / 0.00 -- Battery armor


(Note: For portability, values are stored in Anglo-American units)




Spetsai

With the decommissioning of the Vasilisa Olga (Queen Olga) in 1915, the decision was made to convert the remaining Hydra for cadet training purposes. As part of the conversion she like the Aries also had her quarterdeck raised by 2.2metres making it 5 meters. A new power plant was also fitted to increase the ships speed. At the beginning of 1921 work commenced on the removal of armor to comply with treaty requirements. To prevent a dramatic decrees in draft and to maintain stability the ship carries 520 tones of ballast.

On completion of this work the Spetsai’s depth would have decreased by 1 meter, her water line length would have increased by 2 meters, due to her ram bow, while the ships block coefficient would drop to 0.52. With the decreas of depth the ships freeboard would have increase by 1 meter, improving it seaworthiness.



Length, 104.0 m x Beam, 15.8 m x Depth, 4.4 m
3791 tonnes normal displacement (3021 tonnes standard)

Main battery: 4 x 7.6-cm
AA battery: 4 x 4.0-cm
Light battery: 6 x 1.3-cm

Weight of broadside: 28 kg

Armor deck, average 2.5 cm

Battery armor:
Main, 3.8 cm shields


Maximum speed for 14655 shaft kw = 24.00 knots
Approximate cruising radius, 9400 nm / 14 knots

Typical complement: 242-314


Estimated cost, $1.387 million (£347,000)

Remarks:

Oil firing.

Ship has slow, easy roll; a good, steady gun platform.

Excellent seaboat; comfortable and able to fight her guns
in the heaviest weather.

Ship is roomy, with superior accommodation and working space.

The actual miscellaneous weights carried is 180 tonnesthe remaing
520 tonnes is Ballast


Distribution of weights:
Percent
normal
displacement:

Armament ......................... 8 tonnes = 0 pct
Armor, total ..................... 217 tonnes = 6 pct

Deck 211 tonnes = 6 pct
Armament 6 tonnes = 0 pct

Machinery ........................ 732 tonnes = 19 pct
Hull and fittings; equipment ..... 1284 tonnes = 34 pct
Fuel, ammunition, stores ......... 850 tonnes = 22 pct
Miscellaneous weights ............ 700 tonnes = 18 pct
-----
3791 tonnes = 100 pct

Estimated metacentric height, 0.8 m

Displacement summary:

Light ship: 2940 tonnes
Standard displacement: 3021 tonnes
Normal service: 3791 tonnes
Full load: 4391 tonnes

Loading submergence 1069 tonnes/metre

+++++++++++++++++++++++++


Estimated overall survivability and seakeeping ability:

Relative margin of stability: 1.21

Shellfire needed to sink: 3000 kg = 488.9 x 7.6-cm shells
(Approximates weight of penetrating
shell hits needed to sink ship,
not counting critical hits)

Torpedoes needed to sink: 1.4
(Approximates number of 'typical'
torpedo hits needed to sink ship)

Relative steadiness as gun platform, 71 percent
(50 percent is 'average')

Relative rocking effect from firing to beam, 0.02

Relative quality as a seaboat: 1.59

+++++++++++++++++++++++++


Hull form characteristics:

Block coefficient: 0.52
Sharpness coefficient: 0.39
Hull speed coefficient 'M' = 6.69
'Natural speed' for length = 18.5 knots
Power going to wave formation
at top speed: 61 percent


Estimated hull characteristics and strength:

Relative underwater volume absorbed by
magazines and engineering spaces: 85 percent

Relative accommodation and working space: 177 percent


Displacement factor: 155 percent
(Displacement relative to loading factors)


Relative cross-sectional hull strength: 0.90
(Structure weight per square
metre of hull surface: 332 kg)

Relative longitudinal hull strength: 2.86
(for 6.00 m average freeboard;
freeboard adjustment +2.20 m)

Relative composite hull strength: 1.02

+++++++++++++++++++++++++


[Machine-readable parameters: Spring Style v. 1.2.1]

341.12 x 51.82 x 14.43; 19.68 -- Dimensions
0.52 -- Block coefficient
1916 -- Year laid down
24.00 / 9400 / 14.00; Oil-fired turbine or equivalent -- Speed / radius / cruise
700 tons -- Miscellaneous weights
++++++++++
4 x 3.00; 0 -- Main battery; turrets
Central positioning of guns
Gun-shields
:
0 -- No secondary battery
4 x 1.57 -- Tertiary (QF/AA) battery
:
6 x 0.51 -- Fourth (light) battery
0 -- No torpedo armament
++++++++++
0.00 -- No belt armor
1.00 / 0.00 -- Deck / CT
1.50 / 0.00 / 0.00 / 0.00 -- Battery armor


(Note: For portability, values are stored in Anglo-American units)