[marcusra]

Originally Posted by YachtForums

150 mph? Highly speculative and theoretically questionable. Jet pumps grow exponentially less efficient as speed increases....
.

- 150 knots = 174mph is questionable allright!!! This speeds are usually reached by highpower speed-cats on lakes with absolute flat water!!? Very Hard to imagine those speeds in 40-65ft seas in the middle of the Atlantic!!!? -

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I'm not quite sure about your first part??

Propellers grow exponentially less efficient as speed increases,
BUT i would say that waterjets does the opposit, they grows more efficient when the speed increases!! (But they are useless at low speeds)
This because waterjets takes its water from the layer just under the hull.
This layer of water has a thicknes depending on lots of parameters, like Hull-lenght deplacement, shape of the hull etc.
The big point is that this layer relative to the hull has no speed (like it's following the hull). So the waterjet always accelerates zero-speed water through the jet. But a propeller has to accelerate water that has the speed of the boat (coming against the boat) to increase its speed!!!


Then I'm sure a big problem for this yacht is if the intakes leave the suface of the sea.
This problem is very clear when you for example ride a watercraft (SeaDoo etc.) They goes faster with more people on them, because the intake to the jet stays under the water for "longer" periods then? Smallest wave in great speed and it lifts of and gets air through the jet = speed drops and the engine gets lots of RPM (not sure of the tecnical word... OVERRIDE maby??? ) A good thing is that normal engines usually got "override"-protection.

The question is: Does Gastubines have this type of equipment installed???

[YachtForums]

Originally Posted by marcusra

I'm not quite sure about your first part??

Propellers grow exponentially less efficient as speed increases,
BUT i would say that waterjets does the opposit, they grows more efficient when the speed increases!! (But they are useless at low speeds)

Well... if you say so. What do I know about this stuff! I'm just the administrator here. However, I looked inside a jet pump once. All kinds of things going on there!

Originally Posted by marcusra

This because waterjets takes its water from the layer just under the hull. This layer of water has a thicknes depending on lots of parameters, like Hull-lenght deplacement, shape of the hull etc.
The big point is that this layer relative to the hull has no speed (like it's following the hull). So the waterjet always accelerates zero-speed water through the jet. But a propeller has to accelerate water that has the speed of the boat (coming against the boat) to increase its speed!!!

Just out of curiosity... where did you learn this?

[AMG]

From what I know, there has never been a waterjet faster than a prop boat. Generally the jets lose efficiency around 65-75 knots, probably due to lack of water through the intakes, and also that there hasn´t been a demand to develop waterjets for boats faster than that.
To build a boat like the pictured you can use composite as well as aluminium, a mold is not necessary, but the price tag of USD 35 m will not last long in any case if it should include turbines and whatever will drive it forward even if the speed requirements were downrated to a more realistic 100 knots.
Without having the figures of Destriero right now, I think she was more expensive than that and she had a top speed somewhere just over 70 knots...

[Nismo350Z33]

I know the Miss Budweiser hydroplane uses a helicopter turbine, but is connected to a shaft with a prop. They've been known to go near 200 mph. I don't think it would work in the case of the 150' yacht because it would weigh too much (the hydroplanes are basically wood and fiberglass).

Also, it might go that fast if it used thrust from turbines instead of water jets. Russia used this idea when they built the Ekranoplans that were the size of airplanes, but could travel on water at 400 km/h (about 250 mph!). They skimmed the surface of the water and didn't penetrate it as much as a regular boat would. I think this concept would only work on this yacht if it had wings to provide downforce or lift when necessary. http://www.gizmohighway.com/transport/ekranoplan.htm

-Al (wants an Ekranoplan and a hydroplane for good measure )

[YachtForums]

You are both right AMG and Nismo...

... and I say this because I know a little more than Jessica Simpson on the subject.

I spent 15 years in high speed jet pump development working for Ameriquest Technologies (a Department of the Navy funded research group), Lockheed and Bombardier. During my tenure with Ameriquest, most of my work was concentrated on high speed jet pump development, specifically in the speed echelons we're discussing.

I developed a number of new technologies along the way, including.... intake gullet enlargement/reduction systems, dual-stage axial flow pumps, reflex impeller and stator technology, variable geometry venturis, surface piercing jet pump drives and a variety of thrust vectoring systems.

Contrary to a previous post... jet pumps are capable of providing superior thrust and acceleration, due to their ability to encapsulate (shroud) water and accelerate this flow through a venturi (a venturi is an accelerator), but they DO grow less efficient with increased speed.

That being said... there are designs that have proven favorable for high speed applications, although none of them have ever been made commercially available.

While most of our research was done on a considerably smaller scale than the new Millennium or this "Ventaur Venture", the principles remain the same. I won't expand too much on this...

[marcusra]

For your curiosity I learned this from a cuple of books, when I was to write about the subject in college!!

I don't think I understod all the tecnical English at first!? SO the main problem with jets, is that they grow less efficient, because of the air getting into the system at high speeds???

Writing this I remember another fast Yacht, The 114' "Gentry Eagle". It was a project to beat the world-reccord cross the atlantic... It actually did in 1992 (62hrs 7min with topspeed of 69.6 knots!!) Nowdays it's refitted to a yacht with topspeed of 63knots. Anyhow this yacht has two V16 Diesels conected to waterjets... but the main powersource for high speeds, it's gasturbine is connected to an Arnesson suface-pearcing drive! Before this I thought a lot of why they used this configuration?. Parhaps it's just to get the power into the water in high speeds then??

[Nautilus]

Some drag boats do use waterjets and achieve speed over 200 knots.
But those boats do not need optimum fuel efficiency

So i do believe that it is possible to build a yacht that has top speed of 150 knots.

But that centaur design does look like it's going to have problems getting water inside those outboard jets when at speed.

[AMG]

Originally Posted by marcusra

What about this one!!!

185 feet, 150 knots and TRANS-ATLANTIC RANGE!!!

LOA: 185' LWL: 156' Beam: 30' 1"
Displacement: 560000 Draft: 7'

Engine(s): GE Gas Turbines Engine(s) HP: 19000 Engine Model: LM 1600

Max Speed: 150 Knots

Fuel: 25000 Water: 5000

Hull Material: Aluminum

(Yacht-world.com)

I found some figures of Destriero;

She is 220´long and 42´wide
Displacement 1.000 tonnes
Engines 3 x 17.500 hp GE gas turbines with KaMeWa waterjets
Max speed 66 knots
Fuel 800.000 litres, Water 3.000 litres
Hull in aluminium
Range 3.600 NM at 54 knots...

There is something telling me that 150 knots is out of reach...

[marcusra]

Originally Posted by AMG

There is something telling me that 150 knots is out of reach...

You're right on that one. That's for sure!!



Saw that you are located in sweden to!!
Parhaps you're a member of "KMK" ?? (KMK:U member myself)

[AMG]

Hi Marcusra...

I used to be a member of KMK and KMK:r in the past. I guess that you became a member in 1997 and I was there between 1968 and 1994...
By the way, today I was at their harbour and saw a drag/skiboat passing with a turbine and I think it had waterjet. I was first looking for a helicopter because of the sound, never heard something like that from a boat before. Maybe we have a 150-knot boat at our backyard...

[marcusra]

Originally Posted by AMG

Hi Marcusra...

I used to be a member of KMK and KMK:r in the past. I guess that you became a member in 1997 and I was there between 1968 and 1994...
By the way, today I was at their harbour and saw a drag/skiboat passing with a turbine and I think it had waterjet. I was first looking for a helicopter because of the sound, never heard something like that from a boat before. Maybe we have a 150-knot boat at our backyard...

Saw that one to!!! It was cruising around the boatshow in "vasahamnen"!! It looked like it would need quite flat water to be comfortable!??

[Rene GER]

Is the first picture of "The world is not enough" @ her 70 knots top speed?

[YachtForums]

Originally Posted by René GER

Is the first picture of "The world is not enough" @ her 70 knots top speed?

Hi Rene',

The first pic was taken during the M-140's initial trial runs. The speed at which this picture was taken was in the 45 knot range. During this trial run, the M-140's tabs were being tested for their effect on the hulls ability to achieve plane and the best angle of attack for an efficient cruise.

The tabs on the M-140 are enormous and have a huge amount of travel. They are approximately 10 feet long and 12 feet wide (each), spanning the width of the beam. They are incorporated into the running surface of the aft hull (not behind) and are capable of travelling up or down approximately 3 feet. The first picture was taken with the tabs in the full up position. This picture was distributed to the media simply for effect. This IS NOT an example of how this hull actually runs. It runs very level at top speed with slightly positive bow trim.

To date, the M-140's turbines have not been spooled over 90%, but it has reached 66 knots. It is certainly capable of exceeding 70 knots, but will need the right water, atmospheric conditions and a buyer... because Staluppi won't push the boat. He wants the M-140 to remain new. Most of the testing has been for tweaking so the boat can be delivered turn-key, but also to gain a better understanding of the hulls nuances at high speed.

[sailronin]

About the 183 footer....

A modern diesel burns about .3 pounds of fuel per horsepower output/hour.
19000 hp would burn about 5700 pounds per hour or about 815 gallons per hour. 25000 gallons would yield a 30 hour duration.
Does anyone know what the burn rate per hp/hr is for a gas turbine? I thought is was higher than an internal combustion engine.

Not to mention that you would have to be running on glass seas to get anywhere near that speed....and of course, it would scare the hell out of you.

Dave

[andymullen]

Sorry but we're not talking tarmac here. Maybe on a lake in summer. The Atlantic would break her back within days. Sorry to burst your bubble.

Originally Posted by marcusra

What about this one!!!

185 feet, 150 knots and TRANS-ATLANTIC RANGE!!!


Some other facts:
__________________________________________________ ______________
Builder: Centaur Designer: Langlois & Nadeau

Dimensions


LOA: 185' LWL: 156' Beam: 30' 1"
Displacement: 560000 Draft: 7'

Engines


Engine(s): GE Gas Turbines Engine(s) HP: 19000 Engine Model: LM 1600

Max Speed: 150 Knots

Tankage


Fuel: 25000 Water: 5000

Hull Material: Aluminum
__________________________________________________ _______________

Not to much of a flyingbridge maby... but there's plenty of room under the foredeck I'm shure!!

What about beating every CIGARETTE and APACHE powerboat
.....whit Your MEGA-YACHT??


Forgot to tell you.... This is not just a fantasy-project:

IT'S for sale right now!!

Current Price: US$ 35,000,000
Located in Ft. Lauderdale, FL


(Yacht-world.com)