There are two classes of scooters, toys and tech. The toy scooters like SeaDoo make about 5 to 15 pounds of thrust. They work great in a pool. They generally are not very reliable because they are built as a TOY to be used in situations were your not actually counting on it to keep going. These toy class scooters are 12 volts with a small little battey and have an electric motor that would easily fit in the palm of your hand which drives a fixed pitch prop through a gearbox often using plastic gears--some have metal gears. These scooters usually price out under 500 dollars.
The "real deal" scooters, like X Scooters, Gavins etc, for example price out at thousands of dollars and are very relaible (given the nature of electricity and salt water). These use large (barely held in both hands) direct drive motors running at 24 volts. The motors are large so they can produce power for long periods without heating and the direct drive eliminates the power sucking and unreliable gearbox. The propellers are often variable pitch and these scooters make on low setting about 15 pounds of thrust and on their highest setting more than 75 pounds of thrust.
There are some mid range scooters like the Mako, Apollo and the old tekna that use large 24 volt motors in ABS molded housings. These use essentially the same running gear as the high priced types and run around 1,500 dollars new. These also have up to 75 pounds of thrust.
The old Teknas are fast. Another scooter that shows up often are the Farallons, aluminum body,l ook like a torpedo and go like one! Neither are actually made now though the Mako and most modern Tech scooters evolved from the Tekna type motor/prop/shroud system.
Toy scooter 12 volt motor, you can close your hand around it:
"Tekna" type GE direct drive 24 volt motor--very powerful and large:
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