Thank you JFM!!!

Mapism, your example of your own boat in 1.5m seas is not really valid to the argument. Correct me if I'm wrong but your boat is a heavily built D hulled boat for D speeds only. I already said in my post that there was a bigger difference between D boats and SD boats than between SD and P boats. I acknowledge that a purpose designed D hull is always going to be better at D speeds than a SD or P hull.
Wait, we had no 1.5m waves at all!
It's a F1.5 sea (with a smilie...) and 1 FOOT waves I was talking about. In other words, as flat as a flat thing.
Maybe if you look at my comments in this context, they make more sense?

No need to correct you anyway, 100% correct re. my boat.
As I said, she ..."has a full D hull, and she's possibly a bit heavier than a comparably sized SD boat. All agreed. But in my experience SD boats behaviour is much nearer to D boats, if compared to any P boats".
Which to some extent is the opposite of what you're saying above, though I can see why you wouldn't expect that, just by looking at the hull shapes. But I'm just talking of personal experience here, not of naval architecture.
Frinstance, I cruised in similar sea conditions also on an old 54' Hatteras.
Built as a brick, no stabs, and capable of 18 kts thank to to a couple of big detroit diesels.
In my personal (and admittedly very empiric!) stability ranking of these 3 boats in calm conditions and at D speed, assuming that mine is 1 and the Sq58 is 10, the Hatteras is probably 2 or 3. MUCH nearer to my boat than to the Squad.
Mind, the 1-10 scale is not meant as an absolute measure: it's pretty obvious that the Sq58 is NOT 10 times more shaky than my boat, but it's just to give the idea of the relative SD positioning against full D and P hulls.
All imho, of course.
 
I have to make a decision to have fins, gyros or nothing and I reckon fins is the smart choice out of those 3 options.
Actually there is a fourth way, and on paper it's ideally suited to fast boats, because can be kept completely retracted at high speed (when stabs are unnecessary), and deployed just at slow speed and at anchor.
This system has been around for some years now, though.
And afaik, it's neither widely used nor well known.
Maybe it's a lemon for some reason, I don't know. I only read something about it, but never heard first hand experiences.
 
Actually there is a fourth way, and on paper it's ideally suited to fast boats, because can be kept completely retracted at high speed (when stabs are unnecessary), and deployed just at slow speed and at anchor.
This system has been around for some years now, though.
And afaik, it's neither widely used nor well known.
Maybe it's a lemon for some reason, I don't know. I only read something about it, but never heard first hand experiences.


Is that the Magnus effect stabs? In theory quite a good idea, but perhaps seen as a bit fragile?
 
Congrats Mike. Can't wait for the pictures then. You are also cruising in fabolous waters now IMO. Among the most beautiful in the med. Enjoy!

For JFM that looks serious buisness if they put Olenski on the team to put these exterior tabs. I would not doubt Fairline for GRP issues, they are usually very serious in this department.
In this case I would put my deal breaker for a trial run on the Princess 78 MY, and see how they work and if really did not loose a knot of speed.
 
Is that the Magnus effect stabs? In theory quite a good idea, but perhaps seen as a bit fragile?
Yep, that's the one.
Built by Quantum, who is a supplier of Feadship, Amels, Benetti, Oceanco (among others).
Builders not exactly known for fitting fragile equipments...
But as I said, I actually don't know why just a few yachts fitted them so far.
 
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