Water Jet propulsion

[tripleace]

Thoughts please:

more power?

better with rope and plastic bags?

less maintenance?

More control?

Service costs?

Do we have a good british units?

Does anyone haev one and used it on a long term basis.

It seems from my limited experience a far better way of driving a boat.


www.cleverdic.co.uk

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[oldsaltoz]

G’day Simon.
First, let me say I’m no expert on jet drives but I’m pretty sure the following is correct. Your questions were: -

Better with rope and plastic bags?
Yes to the first part, they tend not to cause damage to rope or the jet unit, however a blockage of the intake will have very definite effect.

Less maintenance?
This depends on how well you want the unit to perform, they are not a long term great performer, particularly if operated in shallow water, and they take in mud and or sand.

More control?
Under power, you can spin the boat end to end (if you have enough power that is) I have to see an outboard do this. But with power cut so is the steering, well all but.

Service costs?
Again, this will depend on the level of performance you want, replacing or overhauling the pump can be very costly.

Do we have a good British unit?
Not sure about this one, perhaps others can advise you here, the New Zealand Hamilton Jet has a pretty good reputation.

Does anyone have one and used it on a long term basis.
Well I don’t but I have ridden in them, and then only commercial operators.

It seems from my limited experience a far better way of driving a boat.
You will find that a prop will push you further for your dollar (sorry Euro).

Well that’s my two bob’s worth on the subject, but again I’m sure others have had experience with these units, so.

Avagoodweekend Old Salt Oz……

 

[tripleace]

thanks for feed back

 

[Viceroy]

Having done considerable research a number of years ago, looking for waterjet propulsion for a displacement cruiser, I found that "Traktor" water jet had the best applicable equipment. Good bollard pull power and many commercial applications. Never the less, there is a loss of efficiency in most if not all water jets when compared to conventional propeller propulsion. I'm still a believer that with appropriate engineering, hull design and application, a very functional installation for cruising vessels could be achieved...with all the benefits that water jets provide. Try <http://www.marinejet.com/> Cheers, Richard.

 

[kghowe]

Isn't that what jet ski's use? Most questions have been answered. Just as an aside see if you can get a look at any of the jet boat adventure videos from New Zealand. They seem to have developed this propulsion pretty well on say 30ft boats. Powering through rocky canyons inches deep a few feet from rock walls at 30kts+. Awesome! Kinda shows what can be achieved, wouldn't recommend it coming out of say Poole or Portsmouth though too many ferries.

regards

 

[Guest]

Only experience is on a 14ft jetboat that I bought as a toy a bit back. These have a virtually flat hull and I am sure that they will behave significantly different to a real sea boat with jets aka Virgin Atlantic Challenger back in the eighties.

To try and answer your questions in order.

They appear to have less power- the 14ft jetboat had twin 85hp's which gave a top speed of 45kts, but can you imagine a 14 footer with a 170hp outboard on the back, got to be 60kts at least if it didnt sink!!

I sucked up a piece ski rope through the water intake, massive amounts of damage to internal gubbins, from memory cost about 1k to put right (Only damaged 1 engine)

My engines needed service every 25 hours, mainly because they are massivly overstressed rotax units.

At low speeds you have virtually no control but over about 6kts much the same as an out drive/board. ( No reverse control at all)

To finish all this experience is with a "toy" boat. But as a toy it was fantastic fun.