Computing

Rock and Rile

Photo Essay

For the second time in four years, the Gibraltar peninsula and the British nuclear attack submarine HMS Tireless have figured in a bitter diplomatic spat between Britain and Spain. This past July, the Tireless paid a six-day visit to Gibraltar, which is claimed by both countries. The visit riled Spanish officials, still seething over a yearlong stay that started in May 2000, when engineers repaired a cracked pipe in the cooling system for the sub's 70-megawatt (thermal) pressurized-water reactor.

Visible in this photograph, taken in Gibraltar's port on 9 July, is the sub's search periscope. It juts up highest from the sub's conning tower, more properly known as the sail. According to Stuart Slade, senior naval analyst at Forecast International Inc. in Newtown, Conn., the cone-shaped top of the periscope houses an omnidirectional radar warning receiver, which gives instantaneous notice of radars operating in the vicinity. In front of the periscope is the T-shaped radar used for navigating and avoiding collisions with floating objects.

Two of the sub's 17 or so sonars are also visible: the matte-looking patch on the side of the ship's hull is a flank array, which detects other subs at long range; and the bullet-shaped unit that a seaman is hanging on to is the passive-intercept sonar, which fixes an enemy sub's position for aiming a torpedo at it. Not visible is the antenna unit, which retracts into the top of the sail, used to intercept and monitor radio and radar off foreign coasts. It looks like an oversize beehive with oddly shaped appendages, Slade says.

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