Stabilizers for Blue Angel, engineering question

BartW said:
First night at anchor, with stabs, lumishore UWL's, my family, and lots of wine,
by the way this is RED dot bay here
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That's great, after all the umming and ahing and headaches during the planning and executing you finally have what you want.;)

BartW=The new blingmeister?

:cool:
 
taz said:
That's great, after all the umming and ahing and headaches during the planning and executing you finally have what you want.;)

BartW=The new blingmeister?

:cool:
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Blingmeister !
A few years ago i would feel insulted, now i love it :) :)

No no np no
Swmbo wants to go skinny diving,
NOT with our kids around !
Who wants to see his own mum naked :(
 
So, Bart, you have made a great job of the hydraulic platform; and now the stabilisers too. What's next - touch-and-go helipad? Submarine? :D

Hope to see you in France across the summer.

Cheers
Jimmy
 
BartW said:
I'm sure hydraulics can only do a segment, and my electrics can do a full circle,
hey jfm inventd a nice app for that, but I'm afraid he nor cmc will earn a lot from this :)
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Hang on a min, B.
The idea of inverting the fins at zero speed is not as trivial as it might seem.
Just think about it: while at anchor, if there's any "swim" effect of the fins which you're interested to avoid, is the forward one which jfm described.
And while I agree that typically even a light breeze on the boat nose would be enough to neutralize it, surely there's nothing wrong in avoiding it altogether.
Now, it would be sufficient to rotate the fins 180° upon startup of zero speed mode to get rid of that effect completely, and avoid any situation like the one jfm described.
Of course it isn't a killer feature, but it's still one which only electric system would allow, and at no additional cost.
Well worth mentioning to Mr.AC of CMC, imho, and hear his opinion.
After all, if he agrees that it makes sense and he doesn't see any problem with that, for them it should be just a matter of updating the software, hence enabling the feature also in the existing systems - yours included, obviously.
You could even suggest him to call that "jfm mode"... :D
 
MapisM said:
Hang on a min, B.
The idea of inverting the fins at zero speed is not as trivial as it might seem.
Just think about it: while at anchor, if there's any "swim" effect of the fins which you're interested to avoid, is the forward one which jfm described.
And while I agree that typically even a light breeze on the boat nose would be enough to neutralize it, surely there's nothing wrong in avoiding it altogether.
Now, it would be sufficient to rotate the fins 180° upon startup of zero speed mode to get rid of that effect completely, and avoid any situation like the one jfm described.
Of course it isn't a killer feature, but it's still one which only electric system would allow, and at no additional cost.
Well worth mentioning to Mr.AC of CMC, imho, and hear his opinion.
After all, if he agrees that it makes sense and he doesn't see any problem with that, for them it should be just a matter of updating the software, hence enabling the feature also in the existing systems - yours included, obviously.
You could even suggest him to call that "jfm mode"... :D
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Yup, you got it mapism. Seriously, though I love my fins as you know, the "swim forward" effect is a pita on those (few) nights with a swell but no wind

My guess is the fin makers will be worried about the boat driving off with the fins pointed forward. They can write software that rotates the fins into the correct trailing mode as soon as the GPS sees 2 knots, i suppose, but they will want to make it as fail-safe as possible

But you are correct: this is just some software
 
sorry, but couldn't there be this option SWELL - NO WIND on the el. stabs and work 100% opposite? Why bother a bit ahead and a bit astern? I doubt the pull on the anchor is going to be serious enough to drag, but it would make sure the anchor is stretched and you don't go messing other boats dinner :p
Or to put it another way, how bad is the stabilisation going to be with the fins pointing the wrong way? Doubt its going to be worse than the Mitsu roto things

V.
 
vas said:
couldn't there be this option SWELL - NO WIND on the el. stabs and work 100% opposite? Why bother a bit ahead and a bit astern?
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My point exactly. You can even push the concept further, and have the fins working the other way round whenever used at zero speed, period.
And re. jfm objection above, well, why stabs builders should be worried about the boat driving off with the fins pointed forward?
Surely there are higher chances for that to happen with fins pushing the boat ahead...
...and if an anchor begins dragging due to the fins thrust, it means that it wasn't a proper anchorage, to start with!
Otoh, I can't disagree on the general principle that builders (of anything, coming to think of it, not just stabs) could be very cautious in applying lateral thinking innovations like this, unless they can be used to sell the thing.
And as I said, clever as it might be this feature, it surely isn't a major selling point...
 
MapisM said:
I forgot to mention, B: right now, we are anchored in a rather exposed spot, and our boat is rolling like a pig.
We come here occasionally, because it's a gorgeous spot for snorkeling inside some caves - more about that later on in another thread... :cool:.
Anyhow, there's an SL92 anchored just in front of us (stunning vessel btw), and - you guessed it - she's stable as a rock.
Ok, much bigger and heavier hull, but I can even see the foam along the hull sides, created by the fins movement, so it's pretty obvious that the stabs are doing a great job. And as you know, SL fits CMC as standard.
Bottom line, if on BA the stabs effectivenss is anywhere near what I'm witnessing, well, I can tell you that you have excellent reasons to be happy of your choice! :)
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Allow me to answer your post in Rob’s thread here;

Last week and the week before we were around st Tropez,
Pamplone (Niki beach, Tahiti beach etc…. are probably the busiest boating area’s in the med, )
I never understood why boaters want to be anchored there, as you’re shaking permanently due to all the passing boats / super yachts at planing speeds.
I can assure you that this time was the first time we enjoyed our stay there because of the stabilisers.

When we left St tropez bay, (at 10kn) and a 90…100ft Mangusta took us over at 25..30knots at very close distance,
We were used that this creates waves and rolling so that guests in sun chairs on the FB shift left and right, and that everything on the tables in the saloon drops down,
But not now, with the stabs switched on, the boat just goes well up and down , and zero rolling.
Elly was on the bow when this happened, and looked at me with a biiiiig smile, while I was on the helm on the FB, and then I was assured that we made a good decision :)
Even guests (my mum fe) warn me when they feel I forgot to switch on the stab system.

For me these stabs do exactly what I hoped for, I have had no single occasion where I thought they are a compromise.
I have to admid that I have zero experience with stabilisers, but I never expected them to be that efficient.

Yes indeed, sometimes you can see the foam / turbulence on the surface near the boat.
Part of that is perhaps the position, I remember very well that you advised “as far as possible from the centerline”
And that’s what we did,
the flange of the stab drive is at 4 cm from the edge of the hull, which makes the lever arm as big as possible,
also,
our drives, are positioned approx. at center of the boat length while on the plane,
our original plan was to place the fins about 1,5m more backwards, I think closer to the COG,
I was a bit concerned that our newer position could create other issues, (re example with a Princess)
But actually I can’t notice any disadvantage of the position they are placed,
Moreover,
In this position the fins have a slightly “bigger “ angle from vertical,
Again a advantage for efficiency ?
All this are just my own thoughts, no real evidence, nor opinion from CMC. …

Then there is the position of the movement encoders (rate gyro’s)
CMC advised to place them somewhere on the centerline,
I have placed them quite high, in a cupboard, about 1,8m above deck level,
In this position the “differential / movements” are bigger then fe on cabin floor level,
Again, I’m wondering what influence this could have on efficiency/ accuracy.. ?

The commissioning from CMC was very limited (mainly my own cause, as I needed to be home quickly for a boaring ceremony with my daughter)
And I had many things to pay attention at, when the boat was re-launched after these big works,
(ao a small leak on a sonar transducer…)
So more tests, comments and advice with a CMC engineer would be appropriate. !

The lo power consumption is not that a big deal, unless here in the port of Toulon,
The first day’s we ran the genny for the stabs all day, but then Elly switched them on, while shore power was on, and sinds then , they run here on 1 x 16 Amp shore connection permanently.
(and no invertor extra power added, actually this was a feature that I intended to add to the switchboard, before I knew that 16 amps is sufficient,)
We have that feature for the airco; that second invertor (basically installed for the stabs) can be used / switched as a “extra” battery power start for the airco
This function is not yet in place for the stabs,
The switching goes automatic, as soon there is genny or shore power, the stabs are connected directly with relay’s to the supply.

Did I mention that during navigation the stabs run via 2 invertors, on battery’s and the main engine alternators, without any issue.

Still hoping to be able to post a report with pics on the installation,
but my mobile connection is so boaringly slow for uploading pictures.
 
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Sounds like it was all worthwile, Bart, even though it seems to have been a stressful experience! Have you noticed any reduction in boat speed? General question to you and other boaters with fin stabs. Are you concerned about swimmers in the water getting to close to the fins when you are using them at anchor?
 
Deleted User said:
General question to you and other boaters with fin stabs. Are you concerned about swimmers in the water getting to close to the fins when you are using them at anchor?
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Not at all. My stabs work only under way... :D
Jokes aside, yes, I can confirm you that if you want to leave zero speed stabs on with folks jumping in the water, you MUST warn them in advance to stay well clear of the fins.
I for one wouldn't want to test their strength against any part of my own body...
 
MapisM said:
you MUST warn them in advance to stay well clear of the fins.
I for one wouldn't want to test their strength against any part of my own body...
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What about other swimmers? I know it's highly unlikely but what would be the legal situation if your stabs injured another swimmer who happened to be passing close by your boat? Would it be sufficient, for example, to have a notice on the side of the hull warning swimmers to stay clear? I'm just wondering as zero speed stabs are going to get more popular and one day sooner or later, somebody will get injured by them
 
TBH, I also think that some accident is bound to happen, sooner or later.
But I have no idea about what would be the consequences from a legal/responsibility standpoint.
IIRC, jfm did put some warning stickers on the hull sides, but whether that would be good enough in case of some serious injuries, I really don't know.
Maybe he checked the legal situation in more details, and can comment with better knowledge of the subject.
 
Could the same be said for the risk of injury from -anchor chain bouncing up/ down in a chop, painters attached to tenders/ water toys etc ( mostly in none stabed boats ,) props from tenders -how about bowthrusters etc ? Some clown playing about with the BT at anchor - with Jo public swimming ?

Generally folks swimming in /arround boats -large or small ,must use a certain amount of common sence?
Stay clear !
Then etiquette -who swims up to touching distance of other folks boats without an invitation ?
Just a thought.
 
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