Technology Background

Divers and swimmers engaged in commercial, military, and recreational activities often need to cover a large area. For example, a search and rescue team might need to sweep a large area of the sea floor. A recreational diver might want to spend time near a shipwreck in a strong current or visit multiple dive sites during one dive.

Using conventional fins is tiring and quickly burns up the scuba divers or free diver's air supply. Exercise also increases the amount of nitrogen dissolved in the blood, increasing the risk of Decompression Sickness (DCS). The conventional solution to this problem is to use an electric powered underwater scooter, such as the ones made by Apollo or Oceanic. However, there are several problems with these devices. Most important is that they occupy both hands. The diver must always keep track of the device or risk losing an expensive piece of equipment, so putting it down to photograph marine life or do some welding is not a good solution.

A superior solution is now available. A diver typically carries 10-25 lbs of lead on a weight belt to offset the buoyancy of his or her body and wet suit. Due to recent technological breakthroughs in batteries it is now possible to replace this lead with ditchable nickel metal hydride (NiMH) batteries. Instead of carrying a heavy battery in a scooter the diver is now carrying no unnecessary extra weight. Additionally, NiMH batteries have almost three times the energy per pound as sealed lead acid batteries. This translates into great weight savings with the same total available power. This idea has been discussed before. The real breakthrough of Jetboots is to use two separate electric motors in separate housing attached to the lower legs and a control unit mounted on the diver's wetsuit or buoyancy compensator. This design allows the user complete freedom of his hands with little extra weight compared to a scuba diver without this propulsion system. The device is securely attached to the diver (the weight belt has a standard quick release feature), so there is no chance of losing the equipment. The following table compares Jetboots to current state of the art scooters.

	Apollo av-1	Oceanic Mako	Farallon Mk7-E	Gavin Scooter	MST Jetboots
System Weight	40 lbs	54 lbs	80 lbs	66 lbs	22 lbs
Weight Excess	40 lbs	54 lbs	77 lbs	67 lbs	12 lbs
Thrust	40 lbs	15-50 lbs	0-~60	0-57	0-40 lbs
Battery	12V 24Ah Lead Acid	24V 18 Ah Lead Acid	24V 18 Ah Lead Acid	24V 18Ah Lead Acid	25.2V 15 Ah NiMH
Cost	$2000	$2495	$3710 with batt & cart	$3500	$3500+

The weight excess column dramatically shows one of the advantage of the Jetboots. Since the batteries take the place of a weight belt and have a much higher energy density than conventional lead acid batteries, the diver need only carry around ten extra pounds of weight compared to a diver not using this system. This, combined with the benefit of hands-free operation, shows that for many applications Jetboots are superior to a standard one-piece scooter.