rwoofer
Active member
Too late for me to enter properly into this debate, but suffice to say that increase in displacement does not necessarily correspond to proportional increase in SA. Certainly in sailing boats the use of chines is there to ensure that boats are more tolerant of weight change than if the chines weren't there. That is assuming the chine is immersed in light weight scenario of course.
Other observation I have is that light weight has most impact on acceleration (kind of obvious really), but not necessarily on top speed. Again from the sailing world, I definitely place more importance on SA in limiting speed than weight.
Hull shape is often what limits light weight from making a big difference to top speed, because once you are on the flat bit, you are either flying or not. My most direct experience is in windsurfing where rocker is a real art to balance lift vs SA.
Edit: Just realised my avatar is of a Phantom dinghy that has one of the most pronounced chines you can get. It is a heavyweights dinghy (I'm a relatively svelte 97kg for a Phantom crew) and interestingly the reason it stays a heavyweights dinghy is that lighter weight sailors don't really go any faster.
Other observation I have is that light weight has most impact on acceleration (kind of obvious really), but not necessarily on top speed. Again from the sailing world, I definitely place more importance on SA in limiting speed than weight.
Hull shape is often what limits light weight from making a big difference to top speed, because once you are on the flat bit, you are either flying or not. My most direct experience is in windsurfing where rocker is a real art to balance lift vs SA.
Edit: Just realised my avatar is of a Phantom dinghy that has one of the most pronounced chines you can get. It is a heavyweights dinghy (I'm a relatively svelte 97kg for a Phantom crew) and interestingly the reason it stays a heavyweights dinghy is that lighter weight sailors don't really go any faster.
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MapisM
Well-known member
Well, yes I do, if you just add "mostly" before "Newton".
But you actually made me LOL, because believe it or no, I would bet that in spite of his 40 reasonably successful years in this business, Mr.LP (short for lunch partner
) doesn't have a clue about what Newton or Archimedes had to say on these matters..When I said that there must be some logic in his simplistic "wet surface" rule, it's just because he always used it empirically, regardless of the physics in the background, and it worked for him and his boats.
What combination of Newton and Archimedes there is behind it, that's anyone's guess, but eventually there must be some sort of correlation with the wet surface, if LP's experience is anything to go by.
Anyhow, fwiw, I don't think the 30/70 proportion which you envisaged (15/35 tons out of 50) holds water, so to speak.
If that would be true, 70% of the volume which is under the w/l at rest in a P boat would still be digging a hole in the water also at 25 knots. Or in other words, the lift created by the V hull design would account for just 30% of the reason why a P boat can travel at 25knots, while (AOTBE) with a D hull you would barely gain a few knots above her hull speed, wasting the rest of the power to move mountains of water all over the place... And that doesn't stand to reason: a P hull has to be much more efficient than that, imho!
If I think of all the P boats I had the opportunity to cruise with, and at the proportion of their hull which sits in the water at P speed, I would rather put my money on the other way round.
And I'm not talking of my old Fountain, which at 70mph literally flew above the water, with probably just 10% of her displacement in the water, if that.
But I suppose we don't disagree on that, and you covered it by saying "until you get to fast stuff".
Of course, it takes much more speed for an airplane for exploiting Newton's 3rd law compared to a boat, but I'm sure you don't need an egg sucking lesson from myself on the difference between air and water...
All that said, in hindsight I agree that fins are much more in Archimedes' rather than Newton's league (particularly in neutral position), as I already recognized in the second to last para of my previous post. :encouragement:
MapisM
Well-known member
Yup, that makes good sense.
But when talking of planing mobos cruising at 25 knots, we are firmly in the "flying" area, as opposed to displacement, which is more typical of traditional sailboats.
And for which I fully agree that weight doesn't matter a lot.
Hugin
New member
A very good, IMHO, layman's read on the drag/friction debate going on here: http://www.soundingsonline.com/features/technical/237792-planing-hull-efficiency
petem
Well-known member
It almost feels like I'm re-opening old wounds but I see that CMC appear to have won the final battle to defend their patent. More info here....
https://plus.ibinews.com/article/eH...er_electric_fin_stabilisers/?nsl=opD0zcpYgjjM
Pete
https://plus.ibinews.com/article/eH...er_electric_fin_stabilisers/?nsl=opD0zcpYgjjM
Pete
jfm
Well-known member
Thanks pete. That would be an interesting read. The link only takes me to a headline not the full text of the decision. Do you happen to know where the text is?
petem
Well-known member
I can't find the article elsewhere but as most of it seems to be a CMC press release here's the full story....
==============
European Patent Office issues final verdict that rejects appeals filed by competitors
CMC Marine has prevailed in a patent dispute over its electric fin stabilisers. The company issued a statement saying that the European Patent Office has issued a final verdict that rejects the appeals filed by competitors to the patent claims.
“This verdict recognises at an institutional level the uniqueness of the Stabilis Electra technology,” said the statement, adding that the fin stabiliser with electrical actuator cannot be replicated by any other company.
The ruling was made on October 8, 2015 at the EPO headquarters in Munich. The EPO had a hearing on the patent dispute in April, following an appeal by marine stabilising companies Abt-Trac, Quantum Control BV, Sleipner Motor AS and Naiad.
“The appeal verdict follows and confirms the earlier Board decision that ended the first opposition meeting held in April 2014, leaving no room for doubt and further justifying the proper patent release,” said CMC in the statement. “CMC Marine is thus confirmed as the only European company that can use an electric actuator for stabilising fins.”
"This verdict, coming from the highest European patent authority, definitively entitling us with the patent for the electric fin stabiliser invention, is a further confirmation that when in 2008 we began producing the first prototypes, we were actually following the right vision,” said Alessandro Cappiello, CMC Marine CEO, in the statement.
“Above all it confirms what the market had already decreed: Stabilis Electra is a powerful invention that has revolutionised a niche market such as the marine stabilisation systems."
==============
MapisM
Well-known member
Well, I'm afraid I gotta disagree with my fellow citizen AC on this point.
The verdict confirms that their "fancy footwork" was good enough for the patent authority, but that alone proves nothing about their vision.
It's the fact that no less than Naiad, ABT, Quantum and Sleipner filed the dispute (to some extent, regardless of the verdict) that goes a long way toward confirming how clever their idea was!
Btw, I didn't realize that practically ALL their competitors formed an alliance of some sort for this dispute. If that alone doesn't speak volumes, I don't know what else does...
LOL, I bet they are now regretting having de facto appointed CMC as the builder of something that all of them would like to copy, if they could!
Hugo_Andreae
New member
Here is the full press release:
The European Patent Office has issued the final, incontestable verdict, assigning the electric fin stabilizer patent to CMC Marine, definitively rejecting the appeal filed by some competitors. This verdict recognizes at an institutional level the uniqueness of the Stabilis Electra technology; the fin stabilizer with electrical actuator, already acknowledged by the market as the most reliable, high-performing system, thus becomes not replicable by any other company.
Cascina, October 2015. On Thursday, October 8, 2015, in the European Patent Office EPO headquarter in Munich (Germany), the Appeal Board officially notified the decision to the opponents, along with CMC Marine representatives. The hearing was called to examine the appeal against the release to CMC Marine, back in April 2012, of an European patent covering a "fin stabilizer actuator electrically operated" product, commercially called Stabilis Electra.
The appeal was promoted by the companies Abt-Trac, Quantum Control Bv, Sleipner Motor As and Naiad, all active in the field of marine stabilization systems.
The EPO highest instance has now officially confirmed to CMC Marine the validity of the invention, recognizing Stabilis Electra’s novelties and inventive qualities, thus confirming beyond any doubt the patent assignment to CMC Marine.
The appeal verdict follows and confirms the earlier Board decision that ended the first opposition meeting held in April 2014, leaving no room for doubt and further justifying the proper patent release. Therefore CMC Marine is thus confirmed as the only European Company that can use an electric actuator for stabilizing fins, mainly intended for the anchor operation.
Furthermore, unique Company on the market, has developed a technology that best meets the performance, compactness and solidity needs required for an ideal stabilization system.
Alessandro Cappiello, CMC Marine CEO, said: "This verdict, coming from the highest European patent authority, definitively entitling us with the patent for the electric fin stabilizer invention, is a further confirmation that when in 2008 we began producing the first prototypes, we were actually following the right vision. Above all it confirms what the market had already decreed: Stabilis Electra is a powerful invention that has revolutionized a niche market such as the marine stabilization systems. I would like to thank all our customers - the most important shipyards in Europe and abroad - for choosing our equipment on hundreds of their vessels, making a substantial contribution to the success of our product. "
D
Deleted User YDKXO
Guest
Odd how the European patent office found in favour of an EU company against 4 companies who are not EU companies? Any bias here?
Also what is a European patent? Does that mean that the other companies can still offer electrically actuated stabs outside Europe? Could an owner buy, say, a set of electric stabs in the USA and ship them into Europe for fitting? And where exactly is Europe in this context?
FWIW in my limited correspondence with Humphree they have never mentioned a patent issue
Also what is a European patent? Does that mean that the other companies can still offer electrically actuated stabs outside Europe? Could an owner buy, say, a set of electric stabs in the USA and ship them into Europe for fitting? And where exactly is Europe in this context?
FWIW in my limited correspondence with Humphree they have never mentioned a patent issue
MapisM
Well-known member
Well, afaik at least Quantum and Sleipner are EU companies, at least to some extent...
Regardless, does that really matter, at the end of the day?
In your boots, I know what I would want for retrofitting stabs on your current boat - and that doesn't include any fins, regardless of what drives them.
Otoh, I also know what I would want for a slower/heavier boat, and that does include fins, but without multiple hydraulic pumps, countless hoses, high pressure compensation tank, VFD, etc....
Jimmyjames
New member
Giro's work on monohulls and Humphree systems are mostly designed for cats. We have two 19m vessels on charter at the moment which have the Humphree tabs fitted (not the funky foils which i spotted at Seaworks) amongst other technical systems on board and they do make a difference. I would imagine given the price they would not be a practical expense for the leisure market.
kashurst
Well-known member
"Also what is a European patent? Does that mean that the other companies can still offer electrically actuated stabs outside Europe? " as long as they are outside the EU group of countries, yes they can sell them, although I suspect CMC will have filed an equivalent US patent, which is the biggy for legal force and effect as you can claim triple damages and costs. (in the EU you can only claim damages and maybe costs)
"Could an owner buy, say, a set of electric stabs in the USA and ship them into Europe for fitting? And where exactly is Europe in this context?" yes you could - once you have paid for the kit its yours to do what you like with it. Getting them installed may be more tricky depending on the agents position. Also CMC can do nothing about boats arriving from outside the EU with electric stabs fitted that infringe their patent.
"Could an owner buy, say, a set of electric stabs in the USA and ship them into Europe for fitting? And where exactly is Europe in this context?" yes you could - once you have paid for the kit its yours to do what you like with it. Getting them installed may be more tricky depending on the agents position. Also CMC can do nothing about boats arriving from outside the EU with electric stabs fitted that infringe their patent.
petem
Well-known member
As I understand it, the EU patent only covers zero speed (at anchor) stabilization. On that basis I wonder if the other manufacturers could sell their stabilizers with this feature disabled in the firmware. Then it would be relatively easy for owners to enable this feature by connecting the ECU to a laptop (using Drivers downloadable via the manufacturer's web site). Alternatively, they could include zero sped stabilization as an 'easter egg' (the code / button sequence for which could conveniently be leaked). Of course the owners manual would say that this is forbidden for units sold to the EU.
kashurst
Well-known member
re Petem - theres no mention in the patent claims about zero speed stabilization.
petem
Well-known member
That was my interpretation of the link provided in JFM's post #61. Quite likely that I've got the wrong end of the stick!
MapisM
Well-known member
Tut tut, are you trying to outclass Italians in cheating with rules, P?
Mind, you don't stand a chance to beat the world masters of this game anyway - i.e. the Germans, needless to say! :disgust:
petem
Well-known member
I see there's no mention of Stabs on the Humphree site now...
http://www.humphree.com/products/
A lack of competition is surely bad news.
http://www.humphree.com/products/
A lack of competition is surely bad news.
D
Deleted User YDKXO
Guest
I think their parent companies are US. It matters a lot because competition always improves the breed, as they say, and boaters would benefit from a wider choice of manufacturers and systems on the market
