Signal-Honolulu-Macco was a partnership formed to explore for oil on Santa Rosa Island in 1948 and 1949. Just after World War II, and fifteen years after Standard Oil Company drilled the island's first hole on Vail Peak, Signal-Honolulu-Macco [a partnership of Signal Oil & Gas Company, Honolulu Oil Corporation, and Macco Construction] entered into a lease agreement with Vail & Vickers to drill for oil.
Honolulu Oil Company geologists Lowell E. Redwine (1911-1982) and Paul McGovney, and Signal Oil geologist Robert E. Anderson (b. 1920), stayed at the ranch house while they conducted field mapping and location preparation. Signal Oil & Gas was the partnership operator, and thus Anderson stayed on for the drillings as well. A total of three wells were drilled: Soledad #1, Garañon #3, and Tecolote #1. Although Signal-Honolulu-Macco was able to use the road previously constructed by Standard Oil as far as Soledad Mountain, this new partnership had to construct about four miles of road from Soledad Mountain northward to their drilling locations. During World War II, an Army encampment had been constructed on Santa Rosa Island and left abandoned after the war. Employees of Signal-Honolulu-Macco rehabilitated several of the barracks for their island operations. Vail & Vickers boat, Vaquero, had been commandeered for the war effort and not returned, and thus supplies for Signal-Honolulu-Macco had to be barged to the island by tow boat and beached at Water Canyon. Santa Barbara Aviation provided air service, and the Santa Fe Drilling Company brought an Ideco H-30 tilt-up rig to the island for the drilling operations.
- Soledad #1 was drilled to a depth of 3,772 feet before it was capped and abandoned in 1948.
- Garañon #3 was drilled to a depth of 3,630 feet before it was capped and abandoned in 1949.
- Tecolote #1 was drilled to a depth of 3,563 feet. Although it had a minor non-commercial showing of oil, it was capped and abandoned in 1949.
Robert E. Anderson remembered:
- “As a rule, the drilling of a well was never shut down, not even for Christmas. In 1948, the companies got kind-hearted however, and shut down the drilling on Christmas Eve day. The plan was to fly back and restart the day after Christmas. Someone jokingly asked me if it ever snowed on Santa Rosa Island. I laughed and said of course not. We all went home, and guess what? It snowed. The plane couldn't fly. So much for my weatherman's forecast. We couldn't get back to the island until almost New Years. That New Year's Day, we all enjoyed a 15 pound lobster caught in a tide pool.”
Although Signal-Honolulu-Macco pulled off Santa Rosa Island in 1949, they retained their rights to use the island's surface for offshore operations until 1953. Today the island's Signal Road commemorates their efforts.