Yellowfin Vairable Pitch Surface Drive

[Willallison]

Yellowfin are producing what must be one of the only commercially available variable pitch surface drives. The advantages are numerous - not the least of which is lower speed efficiencies and no engine overloading.

Any thoughts?

www.yellowfin.com

[Frosty]

I didnt see anything about variable pitching. Infact I didnt see much about any thing exept how wonderfull it is and a lot of pictures of boats.

I have read about surface drives being trimed automaticaly---is this another one.

[Willallison]

Yes - I have to agree - a great deal of marketing hype and not a lot else.
There was a piece on the VSD in the Nov/Dec issue of RINA's Ship & Boat International.
There was also a picture of the unit - which was annoyingly absent on their web site!
The unit has a large diameter hub that allows for a stronger blade attachment - the archilles heel of VP surface drives up until now, as the blade loading varies by so much.
The VSD is available for units 60 - 2000hp and they claim everything from increased efficiency to the lack of need for bow thrusters.
It's an interesting concept so long as the complexity doesn't too much of an issue.....

[Frosty]

Yes a picture of the thing would be helpfull. There was a sketch of it placed amongst other sketches of drives ie jets ,conventional and surface drives. This however seemed to depict a very compact unit with the prop very close to the transom. A measurement that seems illusive and secret.

[marshmat]

Well, the website is sadly lacking in any sort of real information. It looks like it was tossed together by a $7-an-hour high school student and I see precious little data on what the thing actually is, or how it works. Or what their claimed "Total drivetrain and propulsive efficiency 80 to 85% ( Standard in the recreational market 30 -50%)" is based on.... the term 'efficiency' is MEANINGLESS unless you specify how it is defined, and on what basis the comparison is made.
Bottom line is, I'm skeptical. I see a lot of marketing hype, and no engineering data to back it up. I see fanciful claims with not a word as to their basis. And they don't even post a photo of the very thing they're trying to sell. Ordinarily I like new ideas such as this, at least until they prove themselves unworthy, but the Yellowfin VSD drive strikes me as less than worthy.

[Willallison]

Here's a pic of the unit - apologies for the poor quality
A few more details -
Blades can be rotated to vary both pitch and angle relative to the hub. It allows, for instance for the blades to be folded flat against the hub for beaching. It also allows for trimming of the vessel, by varying the angle of the blades top to bottom. Side to side variation provides steering.
They say it produces significant side thrust, making it unsuiatble for single installation. To overcome this they offer a dual output, single input unit.
Cost is supposed to be comparable with a sterndrive, when you take into account the lack of need for bow thruster and trim tabs....

All very complicated, but still rather interesting, I think.

[marshmat]

Taking surface piercing to the limit, eh?
Weird way of steering.... and side thrust would be beyond killer....
I don't quite get the sterndrive comparison though... 'cheaper once you account for not needing a thruster and trim tabs', well, a sterndrive setup doesn't mandate either of those if it's well designed and properly balanced.
Curious how the device will perform under objective testing.... and how it'll hold up after a couple seasons in warm saltwater.

[Willallison]

They're suggesting that with a twin installation, the VSD will give you the same leevel of control as if you had tabs and a thruster, for about the same money.

[Frosty]

That picture posted looks to be on a display of some sorts. I cant see how it works and i cant see the conection with the transom.

So its a swivel steering, up and down trim, reversing blades, pitching blades, feathering blades. probably automatic and conected to the engine management system. Claiming that you will no longer need a bow thruster is exagerated. No matter what you do with your stern it will not do what a bow thruster will do to your bow.

[marshmat]

I'm not sure if it actually swivels or trims, really.... (does anyone know for sure?) it looks from their descriptions like steering, trim are accomplished by changing pitch and rake at different points on one revolution, much like a helicopter steers and trims itself by cyclically adjusting the pitch of its blades.
Still don't get how it can possibly be as manoeuverable, or more so, than a sterndrive with bow thruster.... or how it can possibly be as efficient as they claim when a cursory glance seems to indicate that much of the applied power goes into side thrust.

[Frosty]

Oh,- Ok so you think that the blades are constantly changing pitch and rake to obtain steering by side walk? Well it would explain the huge hub wich probably has some kind of adjustable cam arrangement.

This control (I guess) must be 'fly by wire' Mmmmm electronic stuff!!!

It would be nice to know. Poor management here on some thing interesting. I hope they are listening, Its all very well saying it does 30% this and that at 40% but how?

[marshmat]

More from their website:
# Simple integration of a wide variety of navionics and other equipment into the VSD’s data bus as options
# Minimum of high-integrity service parts, with high-level swap-out of sealed assemblies
It has a main data bus, and their literature seems to indicate all control is fly-by-wire over this data bus. It has a lot of black-box assemblies, apparently not serviceable, that are simply replaced (probably expensively) if they break.
This page, http://www.yellowfin.com/efficiency.html is what really peeves me off and has me convinced that it's going nowhere with the current marketing scheme. Speeds and accelerations are listed in percentages, among other childish mistakes, and what's more interesting than what's provided is what isn't: there is nothing technical, nothing at all about the drive itself or any of its technology, that they're talking about. That's a good sign that someone is pretty clueless. Another good line "compatible with any engine type, even non-marinised engines". Since when does marinising have anything to do with the propeller? It may be a useful device, in some specialized applications, but I can pretty much guarantee that with error-riddled literature and clueless marketing it will go nowhere even if it is a decent machine.
I will have to see some independent tests and results, not stuff from their own press department, before I can come to any conclusions on the technology itself. I can safely say right now that the marketing sucks and their publicists are doing a great job of spreading manure.

[RANCHI OTTO]

Bed website...I have nothing undestud about this system and the figures indicated seam to be unrealistic.

[Willallison]

Proof that there is indeed rarely anything new in engineering...
I was playing in the bath last night (as one does!) when I noticed that the drive unit on Ernie's boat bore a striking resemblance to the VSD....:D

[gonzo]

Outdrives don't require trimtabs. The trim feature is enough to control boat trim. As for bow thruster, this design is still applying power from the stern. That means it can't provide thrust in the bow, which is what a thruster does. A lot of unsupported claims and manipulated data.

[ylpmisfin]

I noticed there has been some debate about the yellowfin drive system.

I can tell you that from first hand experience that the things they claim are true, after all all the claims will have to be substantiated by the relevant bodies before being put into production.

Any craft that has the drive fitted will be much easier to handle, will be able to steer side on and dock side on and the craft can turn on its own axis. There is fantastic effeicency and fantastic control. The website does show a small video clip with the docking on however this is slightly speeded up.

I am available to answer any questions you may have on the drive system apart from the intricate details that make it work as these are top secret.

[RANCHI OTTO]

What about the ratio hub diameter/ prop. diameter?

It seams to be very low...this means turbulances at the hub end.

[Willallison]

RO - I gather that as the drive is mounted much closer to the transom than most other s/drives, the hub runs clear of the water at speed.

ylpmisfin (gotta get yourself a better username!;) ) thanks for the input. I'd be interested in the units performance at intermedite speeds - where surface drives are traditionally poor performers, being optimised for high speed as they usually are....

[RANCHI OTTO]

We have carried out some test in a Model Basin with different hub diameter and we have noted the turbulances behind the hub itself.

The Maierform has patented a bulb installed to the rudder just in front of the hub.

The reduction in power was of 3% abt.

I suggest you to lengthened the hub..nothing else.

I'm interested about this system even if the web is not very cleare (for me!)

[ylpmisfin]

there is very little turbulance in the water as the hub does not sit in the water, only one blade will drive at any one time. The hub will sit directly on the transom giving a much more compact design, after all theres no need for it to hang out any further. Regards the testing you have done i dont think you have understood that the hub is not in the water so your test would not of given the right results if thats how you set it up. You suggested that the hub should be lengthened, well once in production the hub will acctually be much smaller. Thanks

[gonzo]

By your answer, I assume you are related to the manufacturer or you are it. How do you explain your claims that a drive mounted on the stern does the job of a thruster?

[ylpmisfin]

No i am not related neither am i he. I think you have an impression of a very small company, well its quite the contrary. What you have to remamber is that the vessels will be fitted with two hubs twin engine or single engine still two hubs. Side movement can eaisly be acheived using two drives, it can be done using conventional drives but it is very difficult and involves alot of paddle shiffting the yellowfin takes all that trouble away. The thrusters are no longer required. Alot of people do not belive this claim from the looks of this website have a look at www.yellowfin.com and search out the video shows contained on the site they will show a test vessel carrying out these manouvers. thanks

[PetterM]

Some new photage on the website:

http://www.yellowfin.com/video_0.asp
http://www.yellowfin.com/video_1.asp
http://www.yellowfin.com/video_2.asp
http://www.yellowfin.com/video_3.asp

This is a single engine boat....

Some press coverage:
http://www.yellowfin.com/media_coverage.asp
:)

[marshmat]

Interesting system.
Still a lot of unanswered questions, though. And a lot of marketing hype that appears to have very little engineering basis. My comments on one particularly grating slide:

Other new-generation drives VSD
Total drive train efficiency 35% > 45% (another slide says 80-85%)
On what basis? Efficiency can mean a lot of things, and engineers ALWAYS specify how it's defined.
Engine power reduction for the same speed 30% 50%
Again, compared to what?
Increase in speed for the same power 45%
Fuel consumption 30% 50%
No point of comparison given, therefore the percentage is meaningless. Sounds cool but there's no basis given for the claim.
Speed limit 45 knots no speed limit
What competitive surface drive is capped at 45 kts? What's it being compared against? Volvo IPS maybe, which was specifically designed for fat heavy boats?
Acceleration (with a smaller engine) 30% 50% (potentially 75%)
Acceleration... as a percentage?

No point of comparison is given, no clue about the methods used for the calculations....
"Emissions are reduced by 50%"... again, compared to what? The claim appears to be that this thing can get by with a motor half the size of the best competitive drive, but nowhere does it mention what the competitive drive is...
"No fumes on start-up" Since when does this have anything to do with the propeller? This is a motor thing, not a drive thing.
"Minimum of high-integrity service parts, with high-level swap-out of sealed assemblies" Does this mean that when it breaks, you replace a big expensive component instead of a small cheap one?
It's a cool idea and I don't doubt that it could be very practical in some applications. But there are claims going around that are, from an engineering standpoint, meaningless. That has to be corrected if the company wants to be taken seriously by the boatbuilders. Not to mention that so far, it appears that there's only a development model actually built, and the production version (as far as I can tell) has not yet been mounted to a boat, let alone rigorously tested. There isn't even a decent quality photo of the actual device on the site.
I think it's a really cool idea that has a lot of potential. But at present it looks like naive marketing hype is going to kill what is at the core an interesting and innovative concept.

[Frosty]

I agree with Marshmat 100%. My only comment is to say that the naive marketing hype will not only kill the thing but is doing so by the minute in my opinion.
I would have thought that we would have seen some one from the company here by now to answer some of these quieries.

I also feel that the unrealistic claims show a lack of of respect for the general intelligence of the public.

People who would have the money to buy a boat with this drive would not be short of cash and will not appreciate being talked to like an 8 year old.

This type of advertising is doing more damage than good.

[Willallison]

Whilst I agree with some of the things you guys are saying, I think you're getting a bit carried away. I agree the website is rather heavy on hype and light on detail... but then they'd hardly be the first to be guilty of that:
When Volvo introduced IPS they made a great song and dance about improved performance, lower fuel consumption etc etc. Little info about what they were compared to....
They seem to be doing ok with it......

(which brings up one of my gripes... following the release of IPS, there is still an enormous amount of hype about its improvements over conventional shafts. No mention about whether larger sterndrives - without the collision risks - would have been any less efficient. But that's another story)

As to why Yellowfin hasn't appeared on this forum to defend its claims.... has anyone asked them? I mean - I know we are important, but still....;)

[Frosty]

Plenty of hype on soap powder adverts is fine --who cares on a 2 dollar item.

The claims this company is making is unrealistic --we have agreed upon that.

I have heard of Volvo and they have years of reputation behind them.

I have watched the film footage of the unit carefully. The driver appears to leave considerable throttle on at all times walking the boat through forward to flat( fearthered) to reverse.
Using highly pitched blades encouraging side walk with little forward thrust. With practise I have no doubt this manourvarability can be obtained.

I notice that the low speed manouveres are all to port !!! The prop must be therefore rotating opposite to engine rotation--ie right hand rotation prop.

On the high speed footage it turned to starboard, how does it do that with out a rudder?

A descent photo or 2 of the unit would settle my curiosity.

The claims of 40% this and 50% that I shall have to live with untill!!.

As Marshmat says --compared to what?

[Willallison]

The claims this company is making is unrealistic --we have agreed upon that.


Well - let's just say I'll wait to see some verification from independant tests. I neither believe nor disbelieve...

It's early days for this unit. Why not give them credit for being prepared to put the idea out in the public domain so early on in the development phase...

As to the kudos of the company, I think they've been around for quite a while and have some noteworthy developments to their credit. It may just be that you've not heard of them in your part of the world..?

[Frosty]

No I certainly havnt heard of yellow fin.

The point is ,--couldnt they show us a picture of it. Granted they have footage of a boat manouvering -- horray fantastic. How can this be early days when we have seen at least 2 boats fitted with it.

Arent we supposed to ask questions ? are we to just accept what they say? Would it be beyond our capabilities to understand?

Its this silence and distancing themselves from queries that is anoying.

Again they are conspicuously absent. Some thing fishy here.

I hope you dont think I am concerned about this in any way,---Im not.

[PetterM]

I will try to answer some of your questions from an engineering point of view.
All performance claims has been verified by running a 18 ton, 55-foot powerboat with 2 x 700 hp engines, against the same hull with similar power and shaft drives and water jet, and later by back-to-back testing vs. Bravo sterndrives.
Acceleration was taken as the time from 0–30 mph (26 knot) and the improvement as the reduction in this time as a percentage.
Obviously gains will depend on the specific application.
Some photos of the unit here:
http://www.yellowfin.com/media_coverage.asp
Check out the article in motorboat and yachting that explains rather well how this units works.

Best regards,

Petter

[marshmat]

An 18-tonner with Bravos is being used as a point of comparison against twin 700hp surface drives? That's a lot of power to put through a Bravo, especially on a boat that heavy- they're generally meant for smaller craft and would certainly be sluggish and inefficient on something that heavy. Comparison with shaft drives is a good starting point though, since that setup is common on boats like that. How does it stack up against an Arneson?
No doubt that it's a cool idea. But as has been said by many, naive marketing hype is meaningless. Volvo IPS was hardly a new idea; it's simply a small-craft version of the drivetrain our local car ferry's been using since the '70s. The Yellowfin drive is a radical departure from anything that came before and so there is an expectation that solid engineering data- or at least a decent photo of the thing- will be published.
Petter- It sounds like you might be affiliated with the company somehow? Perhaps you could pass on our accumulated advice to the marketing team. I'd like to see this thing succeed, and preferably on engineering merit. I don't want to see a neat idea killed by lousy and ill-informed marketing.

[Pericles]

There are videos on the company website.

http://www.yellowfin.com/VSDTechnology.asp


Pericles

[Pericles]

This British company is offering a complete engine & propulsion package for new build boats that does away with the need for rudders and bow thrusters. The site has videos and reprints of recent articles in the boating press. http://www.yellowfin.com/VSDTechnology.asp

Six units will handle power from 60 hp up to 2000 hp and it is claimed that they could replace twin 875 hp diesels with 510 hp diesels in a Sealine T60 and go 5 mph faster. MBY November 2006.

The Shipnboard article has a good illustration.
http://www.yellowfin.com/pr_shipnboat.pdf

The blades even fold like petals on a flower to allow the boat to take the ground without damage. One engine, two drives!! Roll on May 2007.

Pericles

[Quicksilver]

It's like watching videos of UFO's, what's the deal with the lack of pictures, besides the demo model. If it's for corporate secrecy just say so. The videos could be of anything for all we know.

[Guillermo]

I asked Yellowfin for more info and this is all I got:

"Dear Guillermo
Thank you for your interest in VSD.
We are currently working towards the production launch of VSD and aim to have product in the market in time for next season. Ultimately there will be a range of drives catering for single, twin and multi-engined configurations from 60hp - 2000hp.
We have been working with certain engine manufacturers for some time now and VSD will be available as a total propulsion package (engine and drive system) only. World-wide distribution will be via these engine manufacturers dealers / representatives.
We are concentrating on the new-build market initially, but hope to offer a re-power / retrofit service for existing craft once the new-build market is up and running.
Further technical documentation, photographs and distribution details will be posted on the website as we get nearer to launch....." :?:

[Time]

Has there been any new information released about these drives? or anything relating to their single inout dual output design?

Time

[Pericles]

http://www.yellowfin.com/Financial_times.pdf

http://www.yellowfin.com/Finalcial_Mail.pdf

Getting closer.:)

Pericles

[masalai]

I just found this, whilst backgrounding and trawling for more info, and find it an intriguing and interesting concept that may be of relevance to me, so I emailed for more info today.

We will see what we will see.

[Seahunter]

It has been interesting reading the comments regarding Yellowfin VSD propulsion. First off, I am not a principal or employee of Yellowfin but do have extensive independent knowledge of the project and submit both the pro's and con's of the Yellowfin VSD from my point of view.

The Yellowfin system does work, I have extensively tested and sea trialed it and it has the speed and maneuvering performance claimed. The yet untried concepts of inertial navigation combined with ride control would make this one of the most innovative products to hit the market in years.

However the company has been unable to prove their fuel savings, efficiency and environmental claims even to their contracted customers. The marketing hype, with unsubstantiated figures, has been used over the past four years to extract further investment funds from innocent investors, then an aborted public offering and now, currently towards British taxpayer sources as a last ditch bail out effort. According to one of their Directors, they need 12 million pounds to go to production. Over the past three years they have been unable to even find an engine manufacturer to partner with them. Do the MTU's, Volvo's, Cummins of this world know something we don't?

The current planned selling price of a 500 hp VSD system ( 2 units ) is 74,000 pounds excluding the two engines needed to drive the units and until Yellowfin can raise the capital they are unable to produce. It would take a considerable
fuel savings to justify such a capital expense yet Yellowfin believe their market lies in recreational boating.

Their failure to deliver contacted units has caused one customer to file a claim for damages in excess of one and a half million pounds against them. This factor, together with the lack of support from the marine propulsion industry and the current world economic situation does not bode well for Yellowfin's long term future. It is a pity, as in my opinion, the system, properly developed would be a vast improvement on existing technology.

The problem stems not from brilliant engineering of the designer but from greed, arrogance and egos within the self anointed entrepreneurial division.

[Techboy]

SeaHunter - Strong words. You are quite a distance from the UK, or are you on your travells?

PGNB

[Time]

anyone got more info?

I see beserk designs has a few boats with it in it?

[Seahunter]

As predicted, they have failed miserably. See article in April 2009 edition of Motor Boats Monthly. Page 29

[Time]

don't have access the that article. Care to share what has transpired?

[Seahunter]

Copy of article in jpeg format. Hope it is readable.

[Time]

OK...so i guess it was a flop...good idea poor execution then.
Back to standard surface drives and legs for awhile then.

[Frosty]

failed miserably? is'nt every one else?

[masalai]

Dead thread Frosty, available for "piracy"? & drivel?

[PetterM]

anyone got more info?

I see beserk designs has a few boats with it in it?

I was development manager for Yellowfin for 9 years, and left the company just before xmass 2008. I was involved with all sides of the design, and did all the test driving and demonstrations.
All the prototypes we developed worked really well, especially the version with a splitter gearbox (single engine twin propellers).
We recorded really high efficiencies.
Maneuverability was superb.
Even though I would really like to, I can not comment on the production/commercial side of Yellowfin.

[Time]

So they are definatley not commercially available?

Sounds like it was a good thing, businesses only fail for a few reasons - poor planing or poor finanical management.

Time.

[Seahunter]

I was development manager for Yellowfin for 9 years, and left the company just before xmass 2008. I was involved with all sides of the design, and did all the test driving and demonstrations.
All the prototypes we developed worked really well, especially the version with a splitter gearbox (single engine twin propellers).
We recorded really high efficiencies.
Maneuverability was superb.
Even though I would really like to, I can not comment on the production/commercial side of Yellowfin.

That's interesting PetterM we must have at least passed each other on their stairway on one of my many visits to their offices. I agree with you entirely, there was (is) nothing wrong with the design or engineering or most of the performance claims, the fault lies entirely at the doorstep of the founding Directors who defrauded investors, partners, buyers and governments.

I understand your position on commenting further but I have a feeling that in the end you may have to give evidence in court, when all shall be revealed.

[peter radclyffe]

That's interesting PetterM we must have at least passed each other on their stairway on one of my many visits to their offices. I agree with you entirely, there was (is) nothing wrong with the design or engineering or most of the performance claims, the fault lies entirely at the doorstep of the founding Directors who defrauded investors, partners, buyers and governments.

I understand your position on commenting further but I have a feeling that in the end you may have to give evidence in court, when all shall be revealed.
the concept appears to be the most advanced, affordable system of propulsion that exists, i hope it doesnt get buried in the courts, & that it becomes available to all

[peter radclyffe]

the concept appears to be the most advanced, affordable system of propulsion that exists, i hope it doesnt get buried in the courts, & that it becomes available to all
speaking of which can anyone enlighten us as to what happened to the wankel rotary engine, which daf bought, trussed up & tossed into a cupboard

[marshmat]

speaking of which can anyone enlighten us as to what happened to the wankel rotary engine, which daf bought, trussed up & tossed into a cupboard
Mazda's still building them, in relatively small numbers, but they have their dedicated (rabid?) adherents: http://en.wikipedia.org/wiki/Mazda_Wankel_engine
And there are at least a few shops converting the Mazda engine for marine use: http://www.atkinsrotarymarine.com/

Curious to see what happens to the Yellowfin technology now that the company appears to be toast.... will the engineering die with the business, never to be seen again? Or is there a chance someone else will buy up what's left of the company?

[charlierossiter]

Just to add a postscript.
I recently valued what remained of the boats for the broker's men. Always a sad occasion no matter what the history.
To an extent this looked like a solution in search of a problem?

[PetterM]

Yellowfin goes into administration

(By IBI Magazine/Motor Boats Monthly)

The UK's Yellowfin Ltd, the company behind the Yellowfin propulsion system introduced at the Southampton Boat Show in 2007, has gone into administration.

The company made headlines when its revolutionary variable surface drive (VSD) was first unveiled, but commercial success proved elusive.

Writing as recently as May, the firm's MD, Anne Duncan, said: "Far from fading from view, we have our manufacturing partner lined up and are ready to go.

"The delay in launching Yellowfin is purely down to financial issues, with our decision not to float the company as the markets started to deteriorate."

The company was founded in 2001, and ploughed £13m into the development of the drive system for boats between 6m-46m (20ft-150ft).

Edward Symmons, the company responsible for the sale of the Yellowfin, expects a lot of interest in the technology, saying the drive has a market potential of up to £2.6bn.

"Following the administration of Yellowfin, this niche business is being sold along with the assets of the company. Of most interest to an investor is the patented technology of the business, for which intellectual property rights have been secured," the company said.

"With such a substantial opportunity to complete the final phases of production and bring the technology to market, with or without the existing manufacturing partner company, we anticipate receiving a lot of interest in this sale."

Interested parties should contact Steve Mason at Edward Symmons LLP on 44 (0)20 7344 4500.

(18 September 2009)