Technology explained briefly The development of the water motorcycle

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In our "Technology explained briefly" series, we regularly present masterpieces of construction and special developments. Today: the water motorcycle, commonly called a Jet-Ski.

Summer, sun, water, adrenaline, and fun - Jet-Skiing is a very popular activity, not only during beach holidays. The motorized water vehicles without sides, on which you either stand or sit as you zoom over the water, reach an average speed of 80 kilometers per hour, some vehicles even reach up to 120 kilometers per hour.

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Jet-ski or jetski is not an official name, but the protected trademark of the manufacturer Kawasaki, who markets such boats under this name. Other common terms are water motorcycle as the official designation in Germany, water bob, water scooter or jet bike. The name is derived from the English verb "jet", which is translated as radiate, emit, shoot out, and refers to the propulsion of the watercraft.

The history of the Jet-Ski

• The predecessors of the Jet-Ski were the Water Scooters developed in the 1950s by the British company Vincent. The flat and wide boat had a propeller for propulsion and had a seat with a handlebar. About 2,000 water boats were produced as Vincent Amanda and exported all over the world. However, the European motorcycle manufacturers did not achieve a major breakthrough.

• The idea was then further developed in the USA in the 1960s: The American Clayton Jacobson II was born in 1933 in Portland, Oregon, USA. In the 1940s, his family moved to Southern California. Alongside his studies in physics and technology, Jacobson spent his time street racing, bodybuilding, and working in a car workshop. He was a passionate motocross rider, but probably frustrated with crashing onto the sidewalk at races. After an accident, he began to design a "motorcycle for the water". He quit his job and spent all his time working on his dream of a water motorcycle. By 1965, he had created his first prototype. This special watercraft was made of aluminum and powered by a two-stroke engine. The following year, his second prototype was ready. He made his breakthrough thanks to the switch from outboard engines to a water jet drive.

• He went to Bombardier to get them to buy his jet ski, but they saw no future in it. Then he went to Kawasaki, which was only known for motorcycles. Kawasaki released the first standard Stand-Up Jet Ski in 1973: It had a size of 2.08 m × 0.61 m, weighed 100 kg, and was powered by a 398 cm³ engine. Jacobson eventually sold licenses to the three most well-known jet ski brands today: Bombardier for the Sea-Doo, Kawasaki for the Jet Ski, and the Yamaha Waverunner. Stand-Up Jet Skis can only be used by one driver and are considered the basic form of all subsequent generations. They are still produced today, however, their market share is small.

• A variant from the 1970s is the Wetbike, which could glide on the water like a skibob with two wide runners. It gained great popularity in 1977 through its appearance in the James Bond film "The Spy Who Loved Me": Roger Moore raced on a water motorcycle towards saving the world, and the following year the "Wetbike Watercycle" went on sale. The "motorcycle-like water gliding vehicle" (pdf file DE2539315C3) was patented for Germany in 1978.

• In 1986, Kawasaki introduced the X2, the first two-person water vehicle with a seat.

How the Jet-Ski works

The Jet-Ski operates using a water jet propulsion system, a motor below the water motorcycle sucks in water and ejects it out of the stern. This creates a forward suction and the Jet-Ski moves forward. In detail:

• Water is sucked in through a suction grate on the bottom of the boat.

• The power is provided by a gasoline engine that is operated by electrical ignition.

• The engine drives the water pump and the impeller.

• The speed in the water is created by water exiting through a steerable nozzle that is smaller than the water intake near the rear of the Jet-Ski.

• A small portion of the drawn-in water is used to cool the engine so that it doesn't overheat.

• The handlebar with twist shift is connected to a cable that moves the exit nozzle and thus the water jet, causing the water vehicle to turn accordingly.

• Many water vehicles do not have brakes, so to brake, less gas is given or the reverse gear is engaged.

• In Germany, there is a requirement for a Quick Stop: A band attached to the wrist stops the engine in case of falls.

Where Jet-Skis are allowed to be ridden

In Germany, jet-skiing is subject to some restrictions to protect shipping, nature, and bathers. In general, driving on waterways - i.e. shipping routes - is prohibited. For nature conservation reasons, jet-skiing is also completely prohibited on certain lakes, for example on Lake Constance. To be safe, one should therefore only drive on designated routes where the typical jet-ski figure driving is also permitted.

General rules in Germany:

• It is necessary to obtain a license in order to be allowed to drive.

• The Jet-Skis must yield to all other vehicles.

• Among themselves, they behave as described in the International Regulations for Preventing Collisions at Sea (IRPCS).

• Driving is prohibited at night and when visibility is less than 1000 m.

• Near bathing areas, the maximum speed is 4.3 knots.

• Driving is only allowed between sunrise and sunset and then only between 07:00 and 20:00.

• A Jet-Ski may only be operated under the following conditions: A tear line is present, an official license plate is attached, the driver has a "Sportboat Licence Sea and Inland" and one is riding on the routes marked by blue panels.

The requirements are regulated in the Water Motorcycles Regulation.

Sources:

de.frwiki.wiki, outdoorcentral.de, www.seen.de