Cortes Bank is a chain of underwater pinnacles and plateaus located 137 nautical miles (nm) South by Southeast from Santa Barbara and about 40 nm Southwest of San Clemente Island. Bishop Rock is one of the peaks in the underwater mountain chain that rises to within 6 feet of the surface and is marked by a nearby warning buoy. It was named for the clipper ship Stillwell S. Bishop that struck the rock in 1855 and with a patched hull limped its way back to San Francisco. Nine Fathom spot is about 4.5 miles Northwest of Bishop Rock and also rises to about 60 feet below the surface. Both are noted scuba diving locations featuring clear water and abundant sea life.
Scuba diving Cortes Bank is a truly unique experience. It is an open water seamount where currents sweep clean ocean water over the spot and invertebrates cling to the rocks. Palm kelp fixed to the rocks provides shelter for smaller fish and sealife that hide amongst its fronds. Large clusters of purple hydocoral can be seen throughout the area as well as tuna, yellowtail, large schools of baitfish, sea lions, and occasional sharks. Large black and white sea bass are common sights as well California sheep head. Lobster divers continue to make this spot a top priority to visit during season and free divers frequent the area in the spring and summer for yellowtail, white sea bass, and tuna. Wreck diving can also be done at this location on the Abalonia.
Diving at Cortes Bank can be spectacular but anyone who ventures out there needs to be mentally and physically prepared. On any open ocean dive location one needs to understand that ocean swells and currents are normally present and a flat calm day is rare. When you get good conditions at “The Bank” it will be a dive you will not forget. Sometimes it can be frustrating to get to the bank, but when you do, it can be well worth the effort.
In 1969 a group of promoters bought the World War II surplus troop ship SS Jalisco, renamed her USS Abalonia, and sailed her to the bank intending to sink her in shallow water to form a tax-free island nation and shellfish processing plant. But during the sinking, rough seas broke a mooring line and pushed her into deeper water. Another company planned to build a platform on the bank and form a nation called Taluga, but the US government declared that the bank was part of the continental shelf and was US territory. The wreck of the Abalonia today lies in three pieces in about 30-40 feet of water and scuba divers frequent it often.
On November 2, 1985 the nuclear-powered aircraft carrier USS Enterprise struck Cortes Bank about one mile east of Bishop Rock during exercises, putting a 40-foot gash in her outer hull and damaging a propeller. She continued operations then went into dry dock at Hunter’s Point Shipyard in San Francisco for repairs.
Tanner Bank is a chain of underwater pinnacles and plateaus located 120 nautical miles (nm) South by Southeast of Santa Barbara, California and 35 miles West by Southwest of San Clemente Island This bank rises within 80 feet of the surface and is considered one of the best advanced open water dive locations on the California coast. Similar to Cortes Banks, this seamount is open ocean with exposure to wind, current, and swell. Timing is everything when it comes to a successful day of diving this spot.
Scuba Diving Tanner Bank offers no protection from the weather so anchoring overnight is truly rare. Diving the bank is generally done on a multiple day liveaboard trip when you can take advantage of a weather window and dash out for a day. Because this dive location is so far offshore and exposed to the elements, a diver can get a true feeling of open ocean diving that you cannot get next to land.
Under most circumstances this is considered advanced diving. It is deep and there can be current and surge, but the payoff can be huge. Like any other open ocean dive spot, you have to be willing to roll the dice and see what Mother Nature will dish out.
Because this is an open water seamount currents sweep clean ocean water over the spot and invertebrates cling to the rocks. Palm kelp fixed to the rocks provides shelter for smaller fish and sealife that hide amongst its fronds. Large clusters of purple hydocoral can be seen throughout the area as well as tuna, yellowtail, large schools of baitfish, sea lions, and occasional sharks. Lobster divers have scored well in this location at times and sea stories have been written.