Bofors Defence 75 mm TK75 coastal defence gun system
Description
The now Bofors Defence 75 mm TK75 semi-automatic coastal defence turret system was developed during the 1960s by the then Bofors AB to meet the requirements of the Royal Swedish Coastal Artillery.
The 75 mm gun is 60 calibres long and is mounted in a dome-like turret set into concrete with an underground ammunition department. The cast steel turret armour is 70 mm thick, provides protection against nuclear attack and is usually camouflaged. Ammunition is fed to the gun by an electrical hoist system that can have four or six steps according to the installation.
The gun has a crew of five to seven, traverse and elevation layers, a loader (in the turret) and two ammunition numbers (in the ammunition compartment). The ammunition numbers place the one-piece 75 mm ammunition onto a five-compartment loading table from which the rounds are moved under power to a hoist drum. Using a worm and bevel gear drive the round is fed up the hoist in steps, under microswitch control, to a pendulum where it is moved to a loading tube. The loading tube is supported on the pendulum which moves around the elevation trunnion centre. The raising of the pendulum and loading tube with the round is effected by a torsion spring placed in the trunnion centre. The torsion spring is cocked by the recoil. The loading tube delivers the round to a spring-operated rammer for loading into the breech which uses a vertical sliding block mechanism. The gun is fired by the traverse layer using a foot pedal. After firing, the spent cartridge case is ejected into a separate compartment. Using this semi-automatic ammunition hoist system the gun can fire at a rate of up to 25 rds/min. The hoist system uses three-phase 380 V AC supply and a mains-derived 24 V DC supply. In the event of an electrical failure the hoist system can be operated manually.
The 75 mm gun is hand laid in traverse and elevation by two hand cranks in the turret. For indirect laying follow-the-pointer dials are used. For direct aiming a periscopic sight with dual eyepieces, one for each layer, is used. The fire-control unit normally consists of one radar and one or two optical/laser range-finders which have the same level of protection as the gun installation.
The gun fires four types of fixed 75 mm ammunition, details of which are given in the following table.
Ammunition type Naval target Naval target HE shell Practice shell
shell shell ER
Weight
(projectile, with fuze) 5.73 kg 6.35 kg 5.52 kg 6.55 kg
(charge) 0.62 kg 0.81 kg 0.73 kg n/a
(complete round) 11.5 kg approx 12 kg 11.5 kg 12.2 kg
Muzzle velocity 850 m/s 830 m/s 870 m/s 850 m/s
Time of flight
(to 3,000 m) 4.6 s 4.3 s 4.1 s 4.3 s
(to 6,000 m) 12.6 s 10.4 s 11.2 s 11.1 s
Max range
(20º elevation) 11,400 m 13,300 m 12,000 m 12,200 m
Specifications
Calibre: 75 mm
Length:
(barrel) 4.245 m
Breech mechanism: vertical sliding block
Shield: 70 mm thick steel turret
Diameter:
(cupola) 2.3 m
Height:
(cupola, above ground level) 0.9 m
Total depth of gun shaft: 6 m (approx)
Weight:
(total) 17,500 kg
(4-step hoist) 16,750 kg
(6-step hoist) 17,500 kg
Elevation/depression: +20/-5º
Traverse: ±270º
Rate of fire:
(electrical hoist) 25 rds/min
(manual operation) 15 rds/min
(maximum) 200 rounds in 20 min
Max range: 11,400-13,300 m (depending upon ammunition type)
Crew: 5-7
Status
Production complete with over 100 systems built. In service with Norway, Sweden and several other undisclosed countries. There has been no production or marketing of this 75 mm turret system in recent years. With the increased emphasis being placed on more mobile coastal defence weapons, these 75 mm TK75 coastal defence turrets are to be phased out of service by Sweden in the near future. There are no known plans for the systems used by Norway to be upgraded in the future.
Manufacturer
Bofors Defence AB (A United Defense Company).
С уважением, Exeter
Спасибо! (-) - Ostgott06.05.2006 17:52:43 (60, 0 b)
