The three person submersible Clelia is launched from the A-frame crane. Click image for larger view.
Clelia
Owned and operated by HARBOR BRANCH Oceanographic Institution, Clelia is a PC 1204 submersible built by Perry Oceanographics in 1976 and refitted in 1992 by HARBOR BRANCH to address the needs of the shallow water scientific community. At 23 ft long, 8 ft 3 in wide and 9 ft 7 in high, the Clelia travels at a maximum speed of 3 knots and is classed and certified to a maximum operating depth of 1,000 feet by the American Bureau of Shipping (ABS).
The vehicle can accommodate two scientists/observers and a pilot allowing excellent visibility through the forward acrylic hemisphere. The proximity of the occupants to the bottom (approximately 18") allows tasks to be completed in areas of low visibility. Researchers are afforded an excellent view of the ocean environment through 10 view ports. A hemispheric, 3-ft-diameter window is located at the front end of the sub. Eight 8-in diameter ports are equally spaced around the conning tower of the sub, and one upward view port is in the center of the overhead hatch.
Clelia is outfitted with active sonar, still and video cameras, as well as a seven-function hydraulic manipulator equipped with a suction sampler, clam bucket scoop and jaws capable of handling bottom cores and other sampling devices. The manipulator can lift up to 150 lbs. The various collections are placed in the rotating sampler that allows for both quantitative and qualitative sampling. The Clelia is equipped with still and video cameras. Two 500-watt metal halide lights, ideal for photography, can illuminate an area to near-daylight conditions.
The highly maneuverable submersible is ideally suited for multiple short dives as well as longer duration, more complex dives. The Clelia can be balanced midwater to absolutely neutral buoyancy, providing an extremely stable platform from which to observe, collect samples and shoot photographs and video.
Typical applications include benthic and/or mid-water observations, photo/video documentation and collection of organisms; dump site inspections and monitoring; punch and box coring; search and recovery; bottom surveys; photogrammetric surveys; archaeological site documentation and recovery; and environmental impact studies.
Maintained and operated by experienced and expert pilots and crew, it is further supported by an in-house engineering staff. Working with the support staff, researchers also can add their own equipment, usually other cameras or sampling equipment, to the Clelia. The additional equipment, however, must be tested and certified that it can withstand deep-sea pressures. HARBOR BRANCH also requires that researchers provide their equipment ahead of time to ensure that it can be interfaced properly with the Clelia’s existing equipment.
A typical dive lasts between four to five hours, but the life support system can sustain three occupants for 120 hours.
The Clelia prepares to dive to 1000 feet. Click image for larger view.
Deployment and Features
The Clelia typically is deployed from HARBOR BRANCH’s R/V Seward Johnson I or R/V Seward Johnson II, both of which are equipped with an A-frame crane on the stern. In the span of five minutes, three crewmembers can launch the sub. The A-frame operator lifts the sub from deck and places it into the water, a process supervised by the submersible operations coordinator, who remains in contact with the crew member operating the ship. Another crewmember handles the crane’s lines. Recovering the sub requires the help of one additional crewmember -- a swimmer, who attaches the towline to the emerged sub -- but generally takes the same amount of time as deployment.
The Clelia can be deployed even in moderately rough sea conditions of 3- to 6-ft waves, but the decision to deploy can be subjective. For instance, the submersible operations coordinator may decide not to deploy the sub if waves are coming in both directions, which is known as a “confused sea,” or if swells are detected under the surface. The ship’s captain is responsible for making the final decision.
Exploring the Edmund Fitzgerald
One of the Clelia’s most memorable missions was its survey of the wreckage of the Edmund Fitzgerald, a 729-ft iron-ore carrier that sank in Lake Superior on Nov. 10, 1975. In 1994, a team of HARBOR BRANCH researchers used the Clelia to explore the ship, obtain detailed photo documentation and try to determine the cause of the Fitzgerald’s demise. Over the course of six dives in three days, the Clelia and its crew documented the wreck and discovered some interesting aspects of the carrier that shed some light on the circumstances of its sinking. For instance, a 30-ft deep furrow in the lake floor suggested that the bow struck bottom with considerable force, suggesting that the ship sank very quickly. The researchers theorized that the stern section, which lies upside down and 200 ft away from the bow of the ship, did not separate from the bow until the ship hit bottom. Other evidence suggested that the propeller was still turning as the ship went down.
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