Water jets. Why?

[Deleted User YDKXO]

I was reading the test of the Oyster OM43 in this month's MBY and got wondering why the builder/designer had decided to use water jet propulsion on this boat. It's certainly not for performance, economy or cost reasons. With 2 x 480hp engines, the max speed is 31 knots and, at 20 knots, the fuel consumption is 0.88mpg, both of which are no better than a typical shaftdrive 43 footer and worse than a typical sterndrive or IPS 43 footer. And the thing costs a ludicrous £690,000, doubtless due to the pricey jetdrives. The only advantage I can see of fitting jet drives to this boat is the ability to beach her but who is going to beach a £690k 43 footer?
This is a traditional looking boat and with traditional shaft drive and, say, a £450k price tag, Oyster might be on to a winner. Or is the purpose of the jet drive only to give people with more money than sense something to brag about in the yacht club bar?

 

[Firefly625]

Often wondered the same. I always loved the new Swordsman range...but all the boat testers comments I've read about the Swordsman with jet drives end up stating how it would feel better on shafts...

... you just get the feeling that its simply to be different, something the designers feel will make their boat stand out from the rest. However another way of making your boat stand out is equipping it with best suited propulsion possible to ensure it drives as good as the hull and engines permit! (which rarely seems to be jetdrive!!)

 

[SnaxMuppet]

It certainly does seem strange doesn't it but water jet propulsion must have something good going for it. Don't the the big catamarans that run to France and the Channel Islands use it? I am sure that they wouldn't put it on a vessel such as that without good reason.

Perhaps someone has an idea as to why those big cats use water jet propultion? Is it something to do with them being a cat? I can't imagine why.

 

[pks1702]

Surely it so they can dry out in East Coast Creeks /forums/images/graemlins/smile.gif

 

[[2068]]

It's so they can anchor off Weymouth beach.

dv.

 

[Nautical]

Generally accepted not the most fuel efficient way to power a boat but up side is.

You can chuck as much power at it as you like, the faster you want to go just keep piling in more horespower. Jets are not constrained by rudders, props, P brackets etc , technically you could put so much power in all that would be left in the water would be the intake scoop,

Manouverability, you can control jets with a similar gizmo to joy stick.

Safety, fairly obvious.

Simplicity, not much to go wrong with it, just like a big mechanical pump, very few bits to fall off or fix.

MASSIVE GRIN FACTOR when you want to do crash stops and on a six pence thing.

Agree for a cruising style of thing a bit of a waste.

Now the Sogica 55, you can see the reasoning behind that, you won't get 56 knts with shafts or IPS and surface drive is a pain close too and piddling about on.

 

[Divemaster1]

Safety - No spinning propellers and less damage from striking floating debris or prop fouling by stray lines in the water. The risk of running aground in tidally areas is greatly reduced.

Maneuverability and Performance - You can run ajet without any transmission components, no gears or clutches to break. Moving a deflector or bucket over the jet stream changes the boat's direction and it can be done while under full throttle. ....... Panic stops can often be made within the length of the boat. ... (Grin factor/ safety). Jets are maneuverable; their thrust can be vectored or sent in different directions to move the boat (no need for bow thruster).

Downside is that the tunnel etc. is vounerable to marine growth, so it does require more frequent use than a normal shaftdrive boat... and it gives "less grip" in the water when compared to shaftdirve, so strong side winds may give more leeway than shafts..

 

[nonitoo]

Huge grin factor here http://www.youtube.com/watch?v=pbN4tvQD3Jk

This one is better http://www.youtube.com/watch?v=qBT-2yGXVwU&NR=1

probably others as well but NZ is the mutt's nuts for this sort of thing.

Tom

 

[Alistairr]

Brilliant, but couldn't imagine doing that in a lovely Oyster 43!

Cheers

Al.

 

[Stormin Norm]

I guess the guys in NZ just wanted a big powerboat with Hamilton Jets.... kinda patriotic thing.

The result IMO is excellent. A friend of mine has one and its just the dogs......

Makes a nice change from legs, shafts etc even if it is a bit more expensive.

 

[mjf]

i recently have spec'd up and priced an Oyster sail boat.

Try that too on a 46 and 54.......These are mega expensive builders and whilst I see the quality I still cannot get to grips with their prices.

 

[boatbuilder]

Google VSV Maryslim, jetdrive was the only way to go.