Stabilizers for Blue Angel, engineering question

The debate is drifting a bit imho in the last few posts above. This is, imho, not a battle about which is better out of hydraulic or electric. Both are perfectly fine inho, and in BartW's case electric is preferred becuase of the easy fitting. Nor is it a battle about CMC vs others - there are many good respected manufacturers including CMC.

As I see it, this debate is really on 2 points:

1. whether there is something so magical about electric that it permits use of 60% of the fin area of a hydraulic system. On this point, CMC seem to say the "magic" is faster acceleration of electic fins. I'm very sceptical on this and have put it in the MBS camp. There may be room for more debate on this! BartW doesn't much care becuase this point only affects zero speed stabilisation not underway, and he would I think even be prepared to accept a trade off there for the much easier install of electric

2. Whether there is any heat problem. I've said all along on this that there isn't any heat problem so long as the heat generated can be disipated, and that's easy enough to check by exaimining a system in action. CMC seemed to say there was little heat because the gearbox is like a swiss watch. That isn't even suspected MBS; it is fully certified MBS, though the heat generation in an electric system producing high forces and doing no work seems less intuitive than I thought (see electromagnetic crane discussion). But anyway we should park the heat problem because BartW can check it straightforwardly and we have zero data about disipation ability in the system
 
Naaah, it was all in good spirit from my part, and I hope/think the same goes for jfm.

Of course it is! Petem you have got completely the wrong end of the stick mate. MapisM's and my posts are just a regular every-day-of-ther-week between us :). In maybe 40 years when we are both in an old people's home they will put in our own soundproofed wing of thebuilding so we don't distrub the other patients :-)

But re. paying anyone else for a settlement, not a chance. We would end up arguing with his findings anyway! :)
Yup, ++1 to that. And Pete, you need to read an economics textbook on "comparative advantage" if you think the top expert on any topic is the guy/gal doing that thing for a living :-)
 
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Enclosed some pics on the installation of the Wesmar system. Its an electronic small gyro (pic 231) that drives the hydraulic pumps - which drive the position of the fins. All these pics were taken at Arie de Voom in La Napoule in 2010, where I searched for this system as an option to install on a Majesty 77. Unfortunately, boat contract wasn't signed and fins never got installed, so I dont have feedback on effect.

The blades come in different sizes, we spoke of 6 sq.ft and 9 sq.ft for the Majesty 77 back then. Building depth needed is 420 mm. which might make it a "no go" for Blue Angel... we were planning to run hydraulics off existing systems, so no additional tank was needed. System needs approx 45 liters / 10 gallons.

Personal note to Bart, yes sir, NL is that little cold province up North, and no I dont live in SoF yet - but working on it, haha. Now that my sport boats business is ultra slow I make a decent living with forestry machines, check out www.machinesforestieres.com for details, also some major hydraulics involved !
 
Fine Wanna bet?
See, I'm confident enough in your ability to make the right choices when it really matters, to offer to bet on something which depends entirely on yourself.
I could even go as far as offering to bet our own boats... :D
But MapisM this misses the point. This aint a Sleipner vs CMC debate, at least not in my book. It is about whether or not CMC have something so magical in their electric motor that their 60% fin size works as well as a 100% sized hydraulic fin. My next boat may well have CMC fins, but if you want to offer a bet it is whether I will specify fins 60% of the size of normal ones and rely on something special about the electric actuators (acceleration) to compensate for the "missing 40%". I don't think you'll offer that bet though ?!

Scuse pedantry but I do not agree with "many folks - yourself included - were fearing that the forum would have been overwhelmed by builders posting build threads". My argument was for a principle and I never expressed any fear or expectation about lots of builders overwhelming the forum with build threads. Others maybe did, but not me. So I have no truck with your "history has proved me right".
 
you guys with hydraulic and gyro stab systems would be willing to give approx costs for your systems because it would be interesting to know how these compare against an electric system

ballpark
price of the electric system is similar to one gyro system like the one from NickH, but I would need two of these
the hydraulic system is almost double the price of a electric system, but a big share in that is due to the much bigger installation cost

Maybe after Bart has had his meeting and assuming he buys a system,...
the planning for now is that the system will be installed second half of april
 
a specialist on brushless DC motors, as used in a production plant in automation systems. Here’s a summary of what ‘s been said:
snip/
(in big contrast to the old metal magnet, where It is always the max current that is switched on or off, so maximum heat dissipation)
Um, even if a "specialist in motors" said that I'm afraid it's still bollox BartW. The current through a (non current controlled) motor is at its maximum on start up becuase the windings are a short across the power supply. As the motor spins you get the back emf from the winding passing thru the magnetic field and current falls. If a motor is doing work and you then apply more load, it slows down, and that reduces the back emf (back emf is proportional to rpm) and so the forward current increases, which increases the motor's torque to balance the increased load. (with a computer controlled motor, you apply more current at this point to increase torque and speed back to where you want it to be, despite the higher load). Thus, the current through a non current controlled motor changes according to load and is at its maximum when the motor is stalled and its minimum when the motor is free spinning at max rpm with no load. To say a non current controlled motor always draws max current and therefore makes max heat is just nonsense, whoever said it.
 
you guys with hydraulic and gyro stab systems would be willing to give approx costs for your systems because it would be interesting to know how these compare against an electric system
Mike my hydraulic stabs are about £80k ex vat fitted, but that's fitted in build which is different from retro, to state the obvious. However, the pricing gets a bit more complex: some of the cost is furniture mods to accommodate the equipment, and I also have integrated hydraulics covering fins and bow/stern thrusters (but not any other integrated hydrualics) and the price includes an upgrade to the thrusters valves to give me speed control (well worth having imho) and those snazzy proportional throttle joysicks with a data screen telling me hydraulic pressure and temp and other stuff. Plus, I have two main engine PTOs not one and a 3 phase VFD-driven hydraulic pump, and top-spec filters with restriction gauges, and manual lever control of all valves, and so on, all boxes ticked.

Maybe a base level hydraulic system without all those spec features and with the furniture mods stripped out would be say £15-20k less, on a new build fitted basis. I think that's dearer than one gyro but cheaper than two
 
@MarkNL
Hi and welcome

I've been in sofF a while so know Arie De Boom and Pierre. They've worked on my boats in the past.

AdeB have as you know promoted Wesmar product for some years. While any stab is much better than none, most stab afficionados put Wesmar somewhat down the food chain, due slightly to lack of winglet and the ugly controller, but mostly because of the tall aspect ratio (= more drag) and the one cylinder design. That design causes the hydraulics to put big sideways loads on the bearing set, in addition to the sideways loads from the sea. In most boats, where the cylinder is behind the stab shaft, the sideways force from the hydraulics is often additive to the sideways forces from the sea. Pretty much all the other stab makers use two hydraulic cylinders for this reason (sorry if telling you how to suck eggs but with two cylinders the hydrualics apply merely a torque to the shaft and no sideways load on the bearing set. Only the sea provides the sideways forces)
 
But MapisM this misses the point. This aint a Sleipner vs CMC debate, at least not in my book. It is about whether or not CMC have something so magical in their electric motor that their 60% fin size works as well as a 100% sized hydraulic fin. My next boat may well have CMC fins, but if you want to offer a bet it is whether I will specify fins 60% of the size of normal ones and rely on something special about the electric actuators (acceleration) to compensate for the "missing 40%". I don't think you'll offer that bet though ?!
Of course not, because - as repeatedly mentioned - CMC actually COULD fit 1sqm fins on M3 pronto, if asked.
They might suggest otherwise of course. And they might explain that their recommended fins size has proved fine for Benetti, SL, ISA etc.
But surely I wouldn't bet that they would be able to convince you, in this respect... :D
...therefore, they might well accept to supply you 1sqm fins (or even bigger!) instead of 0.8 or whatever, if you insisted.

Scuse pedantry but I do not agree with "many folks - yourself included - were fearing that the forum would have been overwhelmed by builders posting build threads". My argument was for a principle and I never expressed any fear or expectation about lots of builders overwhelming the forum with build threads. Others maybe did, but not me. So I have no truck with your "history has proved me right".
Well, while I agree that your point was much more focused on the principle, saying that "this forum shouldn't become a place where builders are given free pages to write freestyle about their products in advertorial style" to my simple mind sounded like you pretty much shared the fears expressed by wakeup and others...
Never mind, though, this has zero relevance anyway.
 
we were planning to run hydraulics off existing systems, so no additional tank was needed.
You mean no need for an oil reservoir, I suppose?
Because the compensation tank is normally necessary anyway, at least if the stabs are meant to be used also at rest.
...though maybe those Wesmars weren't actually zero speed, or were they?

Oh, and welcome to the madhouse also from my part! :)
 
... saying that "this forum shouldn't become a place where builders are given free pages to write freestyle about their products in advertorial style" to my simple mind sounded like you pretty much shared the fears expressed by wakeup and others...
Never mind, though, this has zero relevance anyway.
Sheesh. I'm struggling with your reasoning on this thread. My words quoted there are crystal clear defence of a principle only, and not a prediction of anything. Arguing that I was predicting "that the forum would [be]... overwhelmed by builders posting build threads" beggars belief!
 
We need a " red dot bay " rendezvous , this season .
BA ( avec electro stabs) + M2 with build hydraulic
1 hour drinks on each + a set of snooker balls .
Then we will know
Suspect no difference in ball movement on the table

Bart ask then how much research + developement they have done when at factory to arrive @ smaller fin area ?
 
We need a " red dot bay " rendezvous , this season .
BA ( avec electro stabs) + M2 with build hydraulic
1 hour drinks on each + a set of snooker balls .
Then we will know
Suspect no difference in ball movement on the table

Bart ask then how much research + developement they have done when at factory to arrive @ smaller fin area ?

Actually given that there will be 3 boats in SoF with 3 different types of stab system, a comparison test would make for a very interesting read. MBY are you listening!
 
Actually given that there will be 3 boats in SoF with 3 different types of stab system, a comparison test would make for a very interesting read. MBY are you listening!

There's an inclinometer app for ipad, so we can produce accurate data, although two hours of drinking and a bunch of snooker balls sounds much more fun ... :D
 
although two hours of drinking and a bunch of snooker balls sounds much more fun ... :D
+1.
Not to mention that Portofino idea was 1 hour drinks per boat, so by now the bar has already been raised to 3 hours.
I might try to convince a gentleman with the ABT star to join the lot...
...though it will probably take much more than good stabs, to be able to stand up after 4 hours of drinks... :)
 
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