Humphree stabilisation system?

[MapisM]

the ability for 360° is of no practical use apart from maybe maintenance, or installation

On paper, there is another advantage, which as I recall popped to my mind during the debate on your installation: the possibility to run the stabs at anchor with the fins reversed by 180°.
That would obviously eliminate completely one side effect of fin stabs at anchor: their tendency to slightly push the boat forward, which in extremely light wind could be annoying, particularly in crowded anchorages.
I did mention it to Mr.AC, back in those days, but while he agreed that it would be feasible, he obviously didn't consider that worth implementing in their software, because otherwise the feature would be available by now, I reckon.

 

[MapisM]

"Trust to be the best solution" doesn't describe it because electric/hydraulic is a horses-for-courses thing. Certainly electric can be cheaper, and is cheaper/faster to install, especially in retrofits. For the <20-25m it might become the better all-round solution, once some electric actuators without gearbox noise have been invented (which Humphree might have done here - I don't know). Another advantage of electric is 180 degrees rotation, to overcome creep forward at anchor, but the current holder of the patent isn't an outside-the-box thinker imho. If you're wishing to predict the future then forget the electric/hydraulic actuator debate because that is very limited thinking. The future needs much more creativity - for example just flapping like a big rudder on steroids isn't ideal. Mere actuator power choice is a side show when you think outside the box in boat stabilisation and imagine what could be manufactured in the future

LOL, for <20-25m? You must be joking, because as I'm sure you know, those guys build electric stabs with fins larger than THREE square meters, ffs!
Otoh, I sort of agree that AC probably will not invent a way to stabilize a vessel by exploiting the moon gravity force alone, but so far I can't think of anything more innovative than his "side show", in this industry.
Curved fins included, needless to say.

PS: re. noise, c'mon. You know as well as many of us do that when compared to hydraulic pistons and valves, if anything the CMC actuators are quieter.
And before you mention it, no, afaik BartW didn't have to upgrade his A/C system because of the heat generated by the actuators...

 

[Deleted User YDKXO]

Re. pitching, you say "at least on a P boat", but actually I don't even dare thinking what sort of forces would be necessary to stabilize pitching in any boat cruising at D speed.
You could probably achieve a better result by asking the crew to move forward and astern, compared to the what those interceptor things can do....!

The reason I said that was because I saw this https://www.youtube.com/watch?v=qTFJ33WiK9E

I'm sure there's plenty of space on your D boat for some more water tanks

 

[jfm]

LOL, for <20-25m? You must be joking, because as I'm sure you know, those guys build electric stabs with fins larger than THREE square meters, ffs!
Otoh, I sort of agree that AC probably will not invent a way to stabilize a vessel by exploiting the moon gravity force alone, but so far I can't think of anything more innovative than his "side show", in this industry.
Curved fins included, needless to say.

PS: re. noise, c'mon. You know as well as many of us do that when compared to hydraulic pistons and valves, if anything the CMC actuators are quieter.
And before you mention it, no, afaik BartW didn't have to upgrade his A/C system because of the heat generated by the actuators...

Combative post MapisM!
Ref 20-25m, I meant electric could become the no brainer default choice, whereas above that size there might be more of a debate about whether electric or hydraulic; I didn't intend to say you cannot have electric actuators on boats much >25m. Ref moon gravity, maybe you can't think of anything more innovative but watch the fin stabilisation space (over the coming years). Ref curved fins: one season on, my curved fins are outstanding - I need to make a post describing it a bit more. Ref "when compared to hydraulic pistons and valves, if anything the CMC actuators are quieter" I wholly disagree: as regards the gear you place in the accommodation space, hydraulics are much quieter than current generation electric motors/gearboxes with huge reduction ratios (the hydraulic pumps, valves, etc can be mounted remotely in machinery spaces so that all you have in the accommodation space are the cylinders/pistons). In bigger boats this might be academic because the accommodation is not so close to the actuators as it is on a 24m boat.

There are few black and white answers: it all depends on the particular case

 

[MapisM]

LO, combative post? Naaah.... That's something for cold winter nights.
Regardless, happy to not expand this debate further, also because we have already done it to death in the past.

Anyway, it was interesting to hear that some CMC competitor (am I correct in guessing who, by chance? ) thought that the hassle and costs of challenging their patent was something worth affording.
Also because it would be completely silly from their part to do that, if they were only aiming at the small(ish) end of the fins stab market, considering that it's the segment CMC is less interested in.

 

[MapisM]

The reason I said that was because I saw this https://www.youtube.com/watch?v=qTFJ33WiK9E

I'm sure there's plenty of space on your D boat for some more water tanks

Mmm... I'll tell you what.
I'd rather look forward to the next generation, moon gravity based fins system, in the "coming years".

 

[BartW]

Bart, difficult I know, but how do your electric stabs compare to the traditional hydraulic versions, are they just as effective?

We also use ours whatever the sea conditions, but I'm struggling to see the advantage of yours when under way re power use. Your alternator still has to work harder to replace the power used. Or am I missing something simple? Or maybe I'm just simple

I've seen test results from CMC electric stabs, compared with CMC hydraulic stabs, and there the effect of the electric version was clear better,
Perhaps there are other hydraulic stab brands that perform better, perhaps as good as electric,
imho electric driven stabs will alway's have the ability to perform better compared to same sized hydraulic stabs because of less weight / inertion in the system

most people I talk with, about my electyric stabs, have the subjective reaction that hydraulic systems are more powerfull than electric,
I can only say that CMC have sold most systems in the 2m2 to 3m2 fin size , boat sizes >>24m

the advantage of my system underway is that I don't need to run the genny,
of course the alternators need to do more work, but as long they are withing there normal operation mode, thats no issue (140A max each for my setup)
I agree that this advantage is marginal in the total sceme of things, but I prefer to have more power from the alternators than more running hours on the genny
It's indeed very simple

 

[jfm]

Anyway, it was interesting to hear that some CMC competitor (am I correct in guessing who, by chance? ) thought that the hassle and costs of challenging their patent was something worth affording.
Also because it would be completely silly from their part to do that, if they were only aiming at the small(ish) end of the fins stab market, considering that it's the segment CMC is less interested in.

No I don't think you're correct. I think (but I'm not sure of any details) that all or most of the competition are making the challenge together as a kind of consortium. This doesn't amount (as you seem perhaps to think) to some kind of proof that CMC is the best there is, tohugh you are free to make that conclusion of course. CMC are buying electric actuators off a shelf aimed at robotics, where gearbox whine noise isn't a problem, but they have got a patent for electric actuators in general. There should be a big future in electric actuators, and we as consumers would benefit from competition among the full range of manufacturers (Naiad, Trac, Sleipner, Humphree, as well as CMC), but this "unfortunately" obtained patent (I'm choosing my words carefully; I have read all the docs) prevents such competition. We as boat owners, especially in the smaller boat segment, should all want this patent revoked so that competition can happen

 

[jfm]

of course the alternators need to do more work, but as long they are withing there normal operation mode, thats no issue (140A max each for my setup)
I agree that this advantage is marginal in the total sceme of things, but I prefer to have more power from the alternators than more running hours on the genny
It's indeed very simple

I'm maybe missing your logic there Bart, but I'm interested in your thinking. Alternators are only relevant when underway with main engines running. In that mode, PTOs drive hydr stabilisers; there is no need for a genset. The genset hours when underway are therefore not affected. Now at anchor you have the ability on BA to run for 3 hours on batteries, and THAT will save a few genset hours, but it has nothing to do with alternators needing to do more work. Or am I completely misunderstanding the no-genset analysis?

 

[jfm]

less weight / inertion in the system

That needs some maths Bart. You're comparing angular inertia of a vvv fast spinning motor and gear box with a slow moving pair of hydraulic rams and a tiller arm. It is not at all clear, without maths, which has the greater inertia. We already compared real data and showed that sleipner's hydraulic fins achieved a greater radians-per-second value with a 1msq fin that your electric fins with only a 0.6msq fin.
I think inertia in the small quantities we are discussing here is a complete side show as regards the engineering. Electric systems have some important advantages but absence of inertia isn't one of them imho

 

[MapisM]

Well J, of course your final conclusion in post #28 is irreproachable.

BUT, re...

This doesn't amount (as you seem perhaps to think) to some kind of proof that CMC is the best there is, tohugh you are free to make that conclusion of course.

...are you for real?
Of course that's the conclusion I'm drawing. I can't honestly think of another one, as long as we consider rational/economic/technical reasons.
Otoh, there might be folks out there who like a legal fight for the sake of it, but that's another matter altogether, and I have no reason to think that any of CMC competitors are so stupid.

Let me throw down a gauntlet, on the conclusions that should be drawn whenever someone tries to challenge a patent.
I assume that vector fins were patented, weren't they?
If that is the case, I'm betting a virtual Mars bar that nobody on this planet will ever challenge that patent, regardless of how fortunately it might have been obtained.

 

[MapisM]

In that mode, PTOs drive hydr stabilisers; there is no need for a genset.

That's correct of course.
I guess B might have been thinking of gyros in his reply.

 

[BartW]

Yup for me any stabs that can be run off battery power for an hour or 2 at anchor whilst I attempt to consume my lunch in peace would be attractive!

I would be delighted to proove you that this exists, with a lunch on board of Blue Angel

 

[BartW]

I'm maybe missing your logic there Bart, but I'm interested in your thinking. Alternators are only relevant when underway with main engines running. In that mode, PTOs drive hydr stabilisers; there is no need for a genset.

OK, I agree on that,, after reading LJS's post again I understand he's comparing with his PTO driven stabs, there is no real difference underway
while I was comparing with any full genny driven stab system.
I'm here right in between meetings that take a lot of my attention

I'm curious why you took the time to read all the docs regarding CMC's patent ?

 

[BartW]

but the current holder of the patent isn't an outside-the-box thinker imho.

well AFAIK they were the first to use or design electric actuators for fin stabs,
wasn't that a good example of out of the box thinking ?

 

[MapisM]

I'm here right in between meetings that take a lot of my attention

Crikey, in another thread jfm posted an outboards comparison table that he made after googling around during a confcall.
You guys are making me envious, dealing with work and cumulating zillions while browsing a boating forum doesn't sounds too bad.
All I can handle right now is watching some junk TV, posting also on another forum, and sip a G&T...
...but I don't get paid for any of these things! :ambivalence:

 

[BartW]

On paper, there is another advantage, which as I recall popped to my mind during the debate on your installation: the possibility to run the stabs at anchor with the fins reversed by 180°.
That would obviously eliminate completely one side effect of fin stabs at anchor: their tendency to slightly push the boat forward, which in extremely light wind could be annoying, particularly in crowded anchorages.
I did mention it to Mr.AC, back in those days, but while he agreed that it would be feasible, he obviously didn't consider that worth implementing in their software, because otherwise the feature would be available by now, I reckon.

this feature is not available, at least not in the software version that we run,
when I spoke last with AC, (almost a year ago) he mentioned that their biggest concern is to make their system completely "fool proove" for the non technical operator,
he told me about issues on systems, after a prower interruption, or software update, or operator faults.... that sometimes give them headaches
so probably in that respect they don't want to make that 180° mode option.
On some boats the installation doesn't even allow for a 360° turning, spray rails, etc... so they must be carefull when giving that kind of options.

 

[Deleted User YDKXO]

I would be delighted to proove you that this exists, with a lunch on board of Blue Angel

Thanks Bart, I will take you up on that offer!

 

[jfm]

well AFAIK they were the first to use or design electric actuators for fin stabs,
wasn't that a good example of out of the box thinking ?

There are patents for electrically motor/gearbox actuated fin stabilisers dating back decades - 1930s I think. The means by which CMC's application distinguished their system from the older ones is quite something.
Incidentally, Naiad are offering 230v AC servo motor powered fin systems now too. I do not know how they're dealing with the CMC patent.

 

[jfm]

I'm curious why you took the time to read all the docs regarding CMC's patent ?

Just out of my boating interest. I have no professional/work connection with the matter. I read them a couple of years ago - iirc an original patent application, a letter of rejection from the patent office, and a revised application made by CMC that was accepted by the patent office. All in English, by the way, even though done in Italy. AFAIK they are not online but I have plenty of lawyery type friends in Milano and Turino who can get publicly available documents from the register