air defense system to detect the approach of enemy aircraft or missiles. They contained radar and communication equipment and a total crew of around 50 men. This position was expected to give an additional 30 minutes of warning in the event of enemy attack. By 1960, three towers were operating; the plans to build numbers 1 and 5 were eventually shelved.
Of the three operating towers, U.S. Air Force Texas Tower 4 was built in the deepest water. It was located at an offshore location called Unnamed Shoal, 73 nautical miles east of New York City, in water 180 feet deep. The operating decks were 60 feet above the waterline. The design conditions were for winds of 109 knots and for breaking waves 35 feet high.
On September 12, 1960, the tower was hit by heavy seas during Hurricane Donna and was evacuated. Winds of 115 knots and breaking waves exceeding 50 feet occurred. When the storm subsided, the crew returned and found that the tower had been damaged. Plans were made to make major repairs in the spring. A skeleton crew of 28 men was left on the tower to start some repairs; full evacuation was scheduled for February 1, 1961. Unfortunately, before this evacuation took place another storm occurred on January 14-15, 1961, creating conditions too rough for evacuation. The tower was rocked by 74-knot winds and wracked by a succession of large waves 35 feet high, causing it to collapse with the loss of the entire crew.22
The 1980s were particularly cruel to the offshore oil platform industry. Sometimes it is not the “big one” that causes the damage, but rather the cumulative effect of many waves impacting a structure. This is what happened to the Alexander Kielland, a floating drilling platform owned by Phillips Petroleum. The platform, named for a famous Norwegian writer, was used for several years as a drilling platform at the Ekofisk field in the North Sea. Later it was converted into a floating hotel for oil field workers. On March 27, 1980, a fatigue failure caused the loss of the support bracing connecting one leg to the platform. The platform was held in place by anchors, and the multiple legs were used as flotation devices. When the leg failed, the platform capsized, and 132 of the 212 persons aboard drowned. Earlier, I described my own experiences in the North Sea at Ekofisk, including time spent on plat-