je veux ça pour Noël !



<img src="http://www.hnsa.org/doc/banjo/img/banjo1.jpg" border="0" alt="Image IPB" />



<img src="http://www.hnsa.org/doc/banjo/img/pl2.jpg" border="0" alt="Image IPB" />

on dit merci a qui ????

Mk.37

Even before the Mk.35 became operational the development of another superficially similar torpedo, the Mk.37, began. In retrospect, the Mk.37, which is frequently described as the first modern ASW torpedo, is clearly a major milestone in torpedo development. Engineering development of the Mk.37 began in 1946, but its origins are found in WW II projects at Harvard Underwater Sound Laboratory (HUSL) and the Penn State Ordnance Research Laboratory (ORL).

Wire guidance was used in the nineteenth century Nordenfeldt and Sims-Edison torpedoes. The idea had been pursued, though not in conjunction with acoustic guidance, by the German torpedo establishment during WW II and a wire guided shore based German torpedo, called SPINNE (T10), was developed. This torpedo carried over 5000 yards of wire and was built in small quantities. After the war the Royal Navy experimented with wire guidance for torpedoes using SPINNE wire dispensers, but prototypes of useful service weapons were not produced until 1955.

5 In addition to the torpedo modifications, it was necessary to modify the fire control system to provide appropriate control signals and the torpedo tubes to accommodate the wire. In operation the Mk.39 became a "bearing rider", that is it was manually steered to keep it on the line of bearing from the launching submarine to the target. This form of guidance is not particularly efficient and it has other limitations among which we note 1) only one wire guided torpedo at a time can be launched and controlled, 2) for the run time of the torpedo the maneuverability of the firing submarine is limited, 3) torpedo noise masks the acoustic signature of the target and 4) the torpedo on the bearing line indicates the direction to the firing submarine12. In spite of these limitations, the Mk.39 program clearly demonstrated the improved effectiveness of wire guidance against a maneuvering target.

The success of the Mk.39 led to the development by Vitro Corporation and ORL of the Mk.37 Mod.1, a wire guided version of the Mk.37, which began its long service with the fleet in 1960. The guidance system was generally similar to that of the Mk.39 with the incorporation of corrected intercept guidance in addition to the bearing rider mode. Command enabling and new search modes were also introduced. The Mk.37 Mod.1 was longer, slower and heavier than the Mod.0, but it offered greater target acquisition effectiveness was and was more effective against agile submarines.

Mk.37 Mod.0 torpedoes were withdrawn from service and refurbished and reissued as Mod.3; Mod.1 torpedoes were similarly converted to Mod.2 with deliveries beginning in 1967. The refurbishing involved many changes, one of note being the switch from magnetostrictive to ceramic piezoelectric transducers. This change enhanced the acquisition range to about 1000 yards and avoided loss of sensitivity with depth.

The Mk.37 was an excellent antisubmarine weapon until the submerged speeds reached the 20+ knot13 range and diving depths began to exceed 1000 ft. The probability of sinking or seriously damaging a submarine capable of over twenty knots with a twenty-four knot torpedo is unacceptably low (unofficial figures give 10% for the Mk.37) and meeting such threats required new weapons. Significant upgrades of the Mk.37 have been made and its progeny remain in service with many navies as the NT37C, D, E and F which are much faster, operate deeper and boast modern solid state control systems. The US Navy, probably wisely, developed new torpedoes to address the new threats.