November 09, 2006
Faster Than A Speeding Jet?
In my opinion, water jets on RIB’s are a mixed bag. On the one hand, they allow better maneuverability, shallow water navigation, and at high speeds they are more efficient then most traditional propulsion set-ups. But, their efficiency is really a Catch 22.
Though at high speeds jets are rather efficient, operating a boat with a jet at lower speeds is actually inefficient. Jets reduce the horsepower output of an engine by about 20%+ until you hit the sweet spot on the power curve. At that point, the resistance is lowered such where the jet begins to assist as opposed to hurt the efficiency. This is why typically jet boats require larger horse powered engines.
Depending on how the boat is used, the jet is either a good idea or a bad one. For the local harbor cruiser, I'd say no. Similarly I wouldn’t recommend a jet for a patrol boat, harbormaster, or even a local first responder with small boat needs. On the other hand, applications that require high speeds and long range such as interdiction boats and larger SAR boats, a jet is a good choice.
Posted by ribcraftusa at November 9, 2006 09:43 AM
Comments
I was just reading my posting and realized I forgot one of the major benefits of a jet: SAFETY. A jet is a relatively safe propulsion system when you are operating in and around swimmers as there aren't any moving or spinning parts that can cause serious injury like a prop can. Obviously, the operator still needs to be very careful when swimmers are in the water as many fatalities occur as a result of blunt trauma caused by the hull or outdrive unit - not the prop.
Posted by: Fred at November 14, 2006 04:19 PM
