The pilot is a SCUBA diver seated at a control console just behind the pressure hull. In this way the passengers have the illusion that they are alone in the vehicle. In reality the diver/pilot has full control for all maneuvering. A set of three electrical thrusters provide horizontal and vertical movement while submerged. Communications with a surface safety boat are by underwater telephone while submerged and by radio when surfaced. The pilot also provides a running commentary for the passengers using an open-microphone intercom system. The cabin interior contains sufficient oxygen and carbon dioxide absorbent to provide emergency life support for 24 hours.
The control system on the tourist model of SEAmobile is designed so the vehicle cannot go deeper than 50 feet. As soon as this depth is exceeded a pressure switch reverses the vertical thruster to bring it back up to 50 feet. In addition, the submersible is trimmed to be positively buoyant during the dive, with depth being maintained by continuous downward thrust. If there is a power failure the vehicle will simply float back to the surface.
SEAmobile is built to dive deeper. It will be classified by the American Bureau of Shipping (ABS) for a 150-foot operating depth. Depths greater than 50 feet are not that important for tourist operations. Much of the ocean's marine life can be found above this depth and here there is enough light to see without use of external lights. A 50-foot diving experience offers a tradeoff between good viewing for the passenger and the need for the operator to make 8-10 dives a day. In addition, this depth does not pose any particular physiological problems for the external pilot/diver. However, to stay alert and fresh as the guide for the dives, pilots will change jobs every 2-3 hours with the pilot operating the surface safety boat.
If the passengers want to drive SEAmobile, the external pilot can shift control to the inside of the cabin, although he maintains complete override authority. Also, in the case that the pilot gets swept away from his control position, or is disabled, there is a "dead-man switch" that shuts down the submersible and surfaces it.
By the end of 1997 SEAmobile will have made nearly 175 test, training and sales demonstration dives at Catalina. The manufacturer, SEAmagine Hydrospace Inc. forecasts building five to eight SEAmobiles in 1998. The actual number will depend on a number of factors including completion of all ABS-required tests, certification of the vehicle by the U.S. Coast Guard (for operations in U.S.-controlled waters) and the number of orders in hand.
A basic SEAmobile will cost about $195,000 including a full training program for the owner. The 17-foot, 3-ton vehicle can be carried on a standard boat trailer for easy launching at a recreational boat ramp.
SEAmagine Hydrospace also has developed plans for a "Mark II" version. This will be a more conventional submersible which can operate to 150 feet. The external pilot position is removed and all piloting will be done from inside the pressure hull. The company estimates Mark II will cost only slightly more than the recreational version. SEAmobile Mark II will be an affordable, entry-level manned submersible for a variety of commercial, military, and scientific shallow-water users.
While the idea of "A Submarine in Every Garage" certainly overstates the case, the manned submersible: has finally come to the marine leisure market. And you can have one for about the price of a medium-sized powerboat. Put one on your Christmas list!