An integrated shipboard ocean floor research system using a SeaBeam 210 ocean survey system installed on the R/V Ka'imikai‐o‐Kanaloa

An integrated shipboard research system capable of operating in waters of up to2,000 m has been designed and implemented by the Hawai'i Undersea Research Laboratory (HURL), University of Hawai'i. It uses a remotely operated ocean‐bottom survey camera system, a remotely operated vehicle (ROV), the Pisces V submersible, and a multibeam mapping system aboard the 225‐ft RIV Ka'imikai‐o‐Kanaloa. These systems are operated from the stern of Ka'imikai. The Pisces V submersible is deployed and recovered with a mounted Caley telearm and articulated A‐frame system. The integrated shipboard system was designed for a multipurpose use of the R/V Ka'imikai‐o‐Kanaloa for Pisces V daytime operations or nighttime operations with an electro‐optical cable using either the HURL ocean‐floor sidescan or photo and video systems operated at 10 m above the ocean floor. The 1.14‐in. diameter cable is also used to operate the RCV‐150 ROV. In order to obtain a reliable bathymetric database for potential dive sites, a SeaBeam system was installed on the vessel. The installation consists of a hybrid system with classic shipboard electronics and ceramic SeaBeam 210 underhull arrays. The first test results with the ship's bow thruster tunnel closed showed that the SeaBeam 210 system peformed continuously with a normal central beam‐crossing error of less than 10 m. The first field study with the system was conducted during September 1996 over the submarine volcano Loihi, Hawai'i. to resurvey the edifice after an unprecedented collapse of the summit had taken place. The use of both SeaBeam surveys and visual observations with the submersible Pisces V allowed the accurate mapping of newly formed features, such as the 300‐m‐deep. 1,000‐m‐side summit crater, to take place. Almost 300 million tons of rock collapsed into the summit during this event. Magma withdrawal within the magmatic plumbing of Loihi is probably the mechanism by which the summit collapse took place.

Keywords:

• ocean mapping system
• research vessel
• submersible
• survey