If you're looking for a hands-free wearable electric boost while snorkeling or scuba diving, the Jetdive Pro should definitely fit the bill. It's not the first product of its kind, but it is claimed to be the best in several key ways.
Manufactured by Hong Kong company ZTDive, the Jetdive Pro system is currently the subject of a Kickstarter campaign. It's designed to be an alternative to the more traditional "underwater scooters" that users have to hold in their hands, and which partially block their forward/downward view.
The Jetdive gets around these limitations by going on the user's waist. It consists of a waist belt along with two 600-watt electric thrusters mounted on that belt, one at either hip. Users steer simply by twisting their upper body or moving their arms.
The successfully crowdfunded SubCruiser is somewhat similar, but it incorporates a battery- and electronics-containing backpack that is hard-wired to the two thrusters. Last year's self-contained Seakool D2 is definitely a closer match, although ZTDive claims that system is slower, heavier and shallower-rated than the Jetdive.
Users control both of the Jetdive thrusters simultaneously by pressing pushbuttons on top of either one. These buttons allow users to start and stop the thrusters, and to move between three speed settings.
Each thruster delivers 17.6 lb ft of thrust for a combined total of just over 35 lb ft (47.5 Nm) and a top speed of 2.5 meters per second (5.6 mph or 9 km/h) as opposed to the Seakool's 2 m/s. The whole system can descend to a maximum depth of 30 m/98 ft (Seakool: 20 m/65 ft) and reportedly tips the scales at 6.5 kg (14 lb) – that's half the weight of the Seakool.
The main reason that the Jetdive is so much lighter than its closest competitor, however, lies in the fact that it packs much less battery power.
Whereas the Seakool can run for up to two hours per charge, the Jetdive's 99.36-Wh/2,500-mAh lithium-ion batteries are good for just one hour – and that's presumably at the lowest speed setting. Those batteries can be quickly removed from the thrusters and swapped for a freshly-charged optional second pair.
Assuming the Jetdive Pro system reaches production, a pledge of US$759 will get you a setup of your own – the planned retail price is $1,199. The projected retail price for the Seakool D2 is $1,689.
You can see the Jetdive in underwater action, in the video below.
Sources: Kickstarter, ZTDive
The subnado has "cruise control" which lets you "lock on" the throttle (which seem to be the *only* way you can use the JetDrive pro's?) and that is VERY SCARY - being pushed fast through the water without the option of "letting go of the throttle to stop instantly" seems incredibly dangerous. A couple of times now I've been "trapped" against something underwater before it dawns on me that I accidentally activated cruise control and need to disable it to stop the motors...
I also measured their thrust using some pull-scales in my pool, and it matched the specs from their kickstarter campaign. My wife and I use these a lot - they are perfect for snorkeling.