If you're not ready to move up to Yamaha's more expensive Professional line of sea scooters, the Yamaha RDS250 gets a decent amount of depth considering it's one of their bargain-priced Recreational models, plunging down to 100 feet below the ocean waves. Its top speed is only 2.5 miles per hour, but at these prices you're not going to be participating in submarine races. You're going to get a pleasant voyage among schools of fish, underwater vegetation and -- if you live in the right part of the world -- submerged coral reefs. It's not the least expensive Yamaha model -- that would be the Yamaha Explorer, which can only dive to 30 feet and is intended for children. But for what it's capable of doing, a brand new RDS250 will give you a pleasant tour of the undersea universe and will have the Yamaha name on it. (Don't be surprised, though, if you tell your friends that you own a Yamaha and they think it's either a motorcycle or an electronic organ.)
Unlike the Professional models, which use long-lasting lithium-ion batteries, this unit uses a lead-acid battery, sealed to protect it from the salt water in which its designed to operate. (About that salt water: That's what you should be scooting about in. The bouyancy provided by ocean water is what keeps the RDS250 afloat and if you take it in a freshwater pool, pond or lake you're going to gradually sink to the bottom, whether you want to or not, so stick with the salty stuff. Taste the water first if you aren't sure. And, yes, the Great Lakes are freshwater, so if you live in Chicago or St.Louis you're going to have to travel quite a distance to use this.) That battery will last for two hours before it needs recharging, so you should be able to get plenty of sightseeing done before it goes dead.
Delivers a perfect balance of run time and speed. Rated to a depth of 100ft (30m).
Will cruise at speeds up to 2.5mph (4km/h). Combine that with a run time up to 2 hours and the RDS250 is perfect vehicle for back to back dive days.