Waterjet propulsion on Sunseekers

F2-88 · 03-17-2005, 08:04 PM

Just wondering why Sunseeker used waterjet propulsion on 91-93 60ft Renegade
express yachts and then switched to shafts on the Predators from 94 to present.
Thanks.

catmando · 03-19-2005, 02:32 PM

Most likely they wanted more speed. Waterjets are not as fast as props.

AMG · 03-19-2005, 02:54 PM

I have not heard their motivations, but other boatbuilders have experienced that people are not used to handle twin waterjets and also the costs are higher, both purchase and running. Three things the average boater will avoid, eventhough waterjets can perform things that props can´t.

catmando · 03-20-2005, 10:23 PM

The waterjet is the only drive than can actually stop a boat(at least on the 17-21'ers) with the 'bucket' that swings down and directs the water flow forward. Do the Hamilton and KaMeWa drives have that feature?

AMG · 03-21-2005, 04:20 AM

Yes, both the Hamilton and KaMeWas have this bucket on their steerable jets. There are others and they all look a little different, but they can stop the boat and also keep it hovering on one spot. With one steerable jet this can be a little dangerous if you make a full stop from high speed if the steering wheel is not 100% centered. The boat can almost turn over sideways, so you must know what you are playing with. This risk is much lesser on a twin waterjet boat, but instead the stopping power is very high and people onboard can fall over - or overboard...
Some boats (maybe all production boats?) have installed rev-limiters to avoid this kind of full speed reverse, also the bigger yachts who used to flush the quays in the past. It was sometimes pretty fun to see the harbour master helping with the lines and suddenly getting sprayed away by the jet-yachts. It is said that a parked car on the quay was once flushed into the sea...

03-21-2005, 08:37 AM

I have never seen a car washed off the quay, but I did see a young girl get knocked unconscious by a crew member of a 50 meter Codecasa in Saint Tropez when she got hit on the head by one of the docking lines...

AMG · 03-21-2005, 08:48 AM

The car incident could have been in San Remo, I have a vague memory of a newspaper picture some 15 years ago. The throwing lines with a lead or sand filled ball can hurt a lot if you get hit! Normally someone on the quay should catch it and also make sure nobody is at risk, but even the crew can make mistakes when throwing them...