Turbine Question

Technically there is no reason why two turbines cant be used on their own, as long as gearing is optimised and the propulsion system can be tailored to this gearing. Waterjets are usually more suitable in this instance than surface drives. Power for hydraulic thrusters (if electrical ones are not suitable) could be taken off the gear boxes if the pump type and rpm can be geared correctly for low speed turbine running.
I personally would not want a yacht that relies on turbines alone, simply down to reliability, useability and fuel consumption. Maintenance down-times an issue too. You wont be too popular in a marina full of combustable materials (sails ?) either as you light them up
At around the 90 foot size, installation packaging could well be the killer issue. Two turbines will fit snugly enough, but the waterjets of a sufficient size would take some head scratching to fit (once positioned on the transom at the optimum priming height) under a stern platform for example...if a tender garage is wanted as well, things will get tight very quickly. Then you need a gearbox or two. One mahoosive one or two slightly less mahoosive ones.
Finally, the whole hydrodynamic set-up of the yacht needs to be looked at carefully...at the potential high speed offered by turbines, the LCG and running trim will need to be balanced between sufficient aft trim to plane at high speed, vs sufficiently fwd LCG to ensure the waterjet efficiency at hump speeds. Get this wrong and the waterjet will need to go up a size, and you begin to chase your tail to maintain this balance.
I'm obviously generalising here, for all I know you are thinking of a balls-out bespoke one-off build in which case non of the above will really matter.
If thats the case I'm jealous.

There are all turbine yachts out there, I personally know of at least two, one in service and the other in build. There's also Destriero, though she's not really a yacht and hasn't been to sea in a long time. Many of the worlds Navy's have been using COGOG and COGAG power plants for decades, there's no reason why a similar philisophy can't be applied to yachts.

A correctly sized all turbine powerplant is arguably the perfect power plant for achieving high performance in a lightweight small package.

I do however have to disagree with some of the above statements about maintenance and reliability. Turbines if packaged properly, require very little intensive maintenance when compared to their diesel brethren. They are also extremely reliable (one notable exception in my experience being the above mentioned TF50). Think about it, turbines are criss crossing the sky 24 hours a day, do you think that would ever have happened if they were unreliable? No I doubt it, piston engines on the other hand by comparison are much less reliable, mainly due to the far greater number of moving parts within them.

Dont get me wrong, I love turbines. As an advocate of high performance and optimum power to weight, in my little world turbines can offer the biggest punch that will fit in ever smaller machinery spaces.
My comment started with the words 'I personally wouldnt...' Thats me. Whilst there is no technical reason why a yacht could not run well (dynamicaly / performance wise) with turbine power only, if I had the oportunity of commissioning a new-build fast yacht I would probably not rely on turbines alone. If the imaginary yacht was to be chartered, I definately wouldnt rely on turbines alone. Would I have a turbine on said yacht ? Oh yes, snuck in between two diesels if I could design in the required filtration / combustion air demands and exhaust outlet whilst still keeping my ideal superstructure styling, and aft relaxation and tender areas. This is my personal take and answer to the question posted.

ProBoat reference to "Destriero"

You should get ahold of a copy of the Oct/Nov '07 issue of Professional Boarbuilder. There is a really interesting article on the development of the record-smashing transatlantic vessel "Destriero" by Donald Blount...turbine powered

http://www.proboat.com/

Turbine Jet drive

Hi guys,
One thing not mentioned. When the jets are in hover mode, a lot of water gets deflected downward. My boat has small jet drives with diesels and even with the engines at lowest rpm to maintain controll the bottom gets churned up in shallow harbors.
Turbines may not be able to throttle down so much and this could make you not too popular.
As previously mentioned it is a cool thing, there are just trade offs.

We have been involved in the design/build of a number of turbine yachts and military fast craft...The Norwegian MTB and the USN X-craft as two examples and both capable of 60 knots..or close to it. The X-craft is CODOG with MTU 595 diesel and LM2500 turbine on each propulsion line to the Kamewajets.

Interestingly, perhaps, the prototype MTB had a CODOG system also, with Allison 571 turbines and MTU in-line 6 diesel in each jet shaft line. However, the production version uses the Vericor 'twin pack' modules only, in a COGAG arrangement, with an ST18 and an ST40 turbine on combining/selector transmission. During trials of the prototype, the crew discovered that they seldom used the diesel 'maneuvering engine' and the 'lump' was discarded in the production vessels in favor of the flexible COGAG arrangement and weight reduction therein.

All the turbine yachts we have been involved with to date, Destriero being the lone exception, were CODAG, essentially, with 'wing diesels' and a center turbine..three waterjets. The center jet having no steering or reversing bucket and essentially a high-speed ''booster"...and seldom ever run.

move from D-E to T-E

I researched for a long time a good power standby system for a smaler coputing center. A very interesting solution comes from Capstone Turbines.
Build a grid of turbines, you will get all needed power. No oil, 40.000h to the next rebuild etc..

What about to gto from diesel-electric to turbine-electric systems?
With an electric drive you can do all what you want.

If anytime I would hit a jackpot .. I will do it ;-)

G.

Actually..that is an interesting emerging technology and already showing up in smaller packages for cruising sailboats (witness the systems from Glacier Bay as one example..there are others out there and emerging too). Whether diesel or GT prime movers are on the power-generation side of it (or a combination of both), the use of the newer high-power-density elctronically commutated DC motors and generators is going to offer some extraordinary operating flexibility and propulsion layouts. We are looking at that kind of distributed DC powering option for a hybrid ACV vehicle (approx 1000 gross tons) at this very moment.

Mmmm the Norwegian Skjold class with ST40 & ST18's top and bottom? Is that project still having difficulties?

Allison 571's would not be my choice of engine in anything

The Allison 571s in the protoype craft were upgraded and only considered 'place holders' for the planned 601 that Rolls-Royce ultimately bent their pick on and abandoned (they only delivered the ones they were orced to for the P350 yacht project in the UK..and then turned the development effort off entirely). So a new package had to be found and the PW package won out over the other options like the TF100 (twin TF-50s).

Yes, there have been various 'difficulties' with getting the new MTBs (the prototype Skjold has been completely reconfigured and rebuilt to be same as the series rpoduction vessels) in to sea trials..but I'm not at liberty to go in to specifics. As a general comment, once again, the complexities and pitfalls of integrating complex control and monitoring systems was 'underestimated'...

At this point there are three MTB's virtually completed and in the pre-trials fitout and testing phase, with the remaining three close behind. The new government in Norway is making noises about not commissioning any of them and sending them straight to mothballs..but that 'on again, off again' nature of the MTB program has been extant for some 20-odd years now..since we first started the program in 1987.

switch to electric

as my last post I think about a genset of 3 or more turbines. If you can always shut down one for maintenance (remove, change, replace) ther ist no problem. The turbines should produce electrical energy only, if you need less, shut down an turbine. So you can hold the turbines in an optimizes working area. Electrical Pods etc are optimal, or electrical Z-dives etc..

A turbine needs around 60% of the produced energy self for compression. This may be the reason to use diesels. A turbine can run 40.000 h without rebuild and maintenance. This are more than 1600 days ore more tha 50 month! Compare it with your diesel ;-)

COGES - Combined gas turbine and steam turbine

Hi Ju52,

your idea is not so far-fetched. Gas-turbine driven electric propulusion has been done on cruise ships. (Celebrity class cruise ships built at Chantiers de l'Atlantique in France)

The heat from the gas turbines' exhaust is used to generate steam, which powers steam turbines, which in turn again supply power to the grid.

Nice hé?

More info:

Millennium cruise ship, powered by two GE LM2500+ aeroderivative gas turbines, is the world’s first cruise ship to use a COmbined Gas turbine and steam turbine integrated Electric drive System (COGES) configuration. A COGES configuration is a very efficient use of energy: Energy that otherwise would be lost in the exhaust from the gas turbines is captured to produce steam from boilers for the steam turbines. The gas turbine-based system powers electric motors that move the ship through the water and also provides for all on-board power requirements.

The LM2500+ is GE's newest aeroderivative gas turbine. Based on the design of the GE LM2500, this machine delivers up to 25% more power at a simple-cycle thermal efficiency in excess of 39%. It is designed to achieve reliability equal to the precedent setting reliability, 99.6%, of the LM2500. Its high efficiency, reliability, and installation flexibility make it ideal for a wide variety of marine power generation and mechanical drive applications.

The engineering, gas turbine packaging and system integration for COGES was handled by S&S Energy Products, a GE Power Systems business and a GE Marine Engines Marine Systems Supplier. Three additional Millennium-class cruise ships being built for Celebrity Cruises, as well as four Vantage-class ships being built for sister cruise brand, Royal Caribbean International, will use LM2500+ gas turbine-generator sets for main propulsion and onboard power.

Source: http://www.marinetalk.com/articles-...ENNIUMs-Propulsion-System--xxx00024713TU.html

Bruno

Hi,

Some things for sure help to start turbos / diesel engines:

1. Good atomizing.
2. Warmed up suction air.
3. Warmed up fuel.
4. Warmed up combustion chamber / mechanical parts involved.

If diesel oil temperature is at appx. 10-20 deg C, then problems with separation may arise, and in worst case - parafine will settle.

Best, troubleless experince what I had with diesel / gas oil, is when it's treated up to 40-45 deg C.
However, there are some restrictions apply for heating up marine gas/diesel oils onboard. If I'm not mistaken - 60 deg C is a MAX.
But this applies only for storage. It's possible to make temperature higher in a closed/pressurized system.
Warmed up fuel will help to improve ignition / combustion, that's for sure !

But, I think, that all factors have to be considered. Not only diesel oil temperature.

P.S. What do You mean with "Number 2 Diesel" ?

Best regards,

Andrei

Andrei,

This might shed some light on what No 2 is
http://www.biodiesel.org/pdf_files/fuelfactsheets/BTU_Content_Final_Oct2005.pdf

Hi,

K1W1, thanks for a link provided. Are these "Number 1 and Number 2" somehow comparable as Marine Gas Oil (MGO) and Marine Diesel Oil (MDO) ?

Best regards,

Andrei

Andrei,

Here is the price of the former-

http://www.bunkerworld.com/markets/prices/ae/fjr/

I will respond with more details when I can either link or c and p some if you need quicker or better you can always data or PM me

I am currently loaded with over 200 tons of some type of diesel fuel which was sold as Automotive Diesel I am in water in a Nthn. Location and it has a wax point of above 8 deg C so I have my own fuel issues. The Lab tests do not resemble anything with this flash point sold in gas stations. I am waiting to see how the various retained samples resemble the spec sheets we were provided with at the time of last bunkering. We loaded some 190 tons then so the problems we now have originate there I would say.

We are currently waiting for tests to see what other nasty surprises we are in for. One that I have managed to bypass is the suggestion we add hydraulic oil to the fuel to re dissolve the wax formation.

Brain Teaser:

Bearing in mind we are looking for the same stuff we run in cars, is there anyone out here on the boards who can tell me what problems we could have other than viscosity control if we added Hydraulic Oil to normal modern automotive diesel.

Hi,

It looks like we've got far away from turbine question...

K1W1, thanks for a link once again. Yes, looks like it's about MDO/MGO.
But they also can be as DMA/DMX and DMB/DMC.

Here is a link about fuel ISO standards:
http://www.owbunker.com/Services/Fuel+specifier?IsoName

And DNV Petroleum Services can be found here:
http://www.dnv.com/maritime/fueltesting/AboutDNVPS/index.asp

rgds,

Andrei