Sail configurations

This information is drawn from various sources, including the U.S.S. Irex Newsletter, Vol. 9, no. 3, March 2003.

Until she acquired a snorkel in 1946–1947, the Irex resembled a typical “fleet” boat, which had shears to support the periscopes, radar and radio masts. There was a bridge deck half way up the shears, and forward of it a deck for the forward 40mm cannon. The bridge deck extended via a catwalk to the rear of the shears where there was a deck to accomodate the after 40mm cannon.

It is sometimes said that unlike other fleet type boats this after deck lacked a gun, but this was not the case, as this photo clearly shows. The catwalk leading back from the bridge had a railing and extended to the ladder descending from the after gun deck to the main deck of the submarine. Fair weather lookout “nests” were placed on either side of the periscope housing, well above the level of the bridge deck.

There was a heavy gun base built up from the hull to support 5"-25 deck guns both fore and aft, but the Irex had only the aft gun installed, which was not unusual.

From December 1946 to February 1947 a snorkel was installed by the Portsmouth yard, and this required the construction of a large “sail” to smooth the flow of water around the shears. As these photos of 1947 show the sail left everything below the level of the bridge much the same and enclosed the shears only above that level. A catwalk still extended back to the after deck, which now looses its 44mm cannon and perhaps also the ladder leading down to the main deck.

This after deck was an ideal place to lounge when in tropical climes, and so it acquired the name “cigarette deck”. Apparently there was concern that the OOD would dive while leaving someone stranded on the cigarette deck, and so the lookouts were instructed to check first before a dive.

The top of the sail was bulbous in cross section to accommodate the radar antenna and snorkel valve. Noteworthy is that the lookout positions were moved from the shears to turrets projecting out from both sides of the bridge.

During a Portsmouth overhaul in November 1952 (?) the chin-mount gun and aft deck gun were removed, and the sail was redesigned with a much enlarged “chariot” bridge, with lookout positions now brought inboard. The two heavy deck gun mounts were also removed at this time, which made it almost impossible to dive after leaving the yard. This photo shows the new configuration.

In July 1957, the Irex went into the Philadelphia Navy shipyard where the metal sail was replaced with a large fiberglass sail, termed the “North Atlantic” or “FRAM” sail. This located the bridge at the very top. A ladder within the sail went up from the conning tower to a platform deck at the level of the original bridge, from which a second ladder ascended to the bridge at the top. Windows allowed observation from the platform deck during really bad weather, but I don' recall their ever being used for that purpose.

The idea of this new kind of sail was that it was less reflective of radar. Routine maintenance on it seems to have been a pain. This sail remained with the boat until her decommissioning in 1969.

Documents index
History page