[Billy1119]

Carl, while you've already resolved the problem, in defense of BMcF, I was about to ask the same question he did regarding OceanFlyer's post.

[AMG]

Billy, I am defending Carl in this, since we have had similar scenarios in the past, where somebody is helping a supplier by asking innocent questions that could have been asked by anyone. Like you or BMcF.

I became a little curious on BMcF when he commented like this;

"OK..I actually had seen that site but it's been a while."

The reason is I found the website to be almost new...

But now the air is cleared I hope so let´s go on with the topic.

[BMcF]

Thanks for the apology Carl. No worries. Although I must confess that it was I who was actually trying to set a 'trap' so to speak. I suspected I would receive a 'smoke and mirrors' answer to my question...a question that was indeed intended to draw out what kind of wiggly bits performed such miracles. On many forums this is known as 'calling BS' and often done more directly.

AMG, it would have been more accurate, then, if I had said: "I've seen those things before..."...and I'm sure that I saw them on the web some years ago. Can't say I'm in the habit of checking how old a site or URL is ...


I think it best that I return to lurking and the odd multihull post and leave any discussion of stabilization to the experts.

[YachtForum]

Originally Posted by BMcF

I think it best that I return to lurking and the odd multihull post and leave any discussion of stabilization to the experts.

I think it's fair to say you need a "roll eyes" emoticon after that statement.

Wisdom is welcome here and we embrace new technology. However, we will not let this medium be used for manipulation or self-serving promotion. We have some very respectable people on this site, a virtual who's who of sorts. You can "lump" yourself in this category too Mr. McFann.

[BMcF]

Why thank you kind sir..LOL..I've been told I'm a legend in my own lunchtime - perhaps that is more accurate than I 'appreciated'...

[Billy1119]

Originally Posted by AMG

Billy, I am defending Carl in this, since we have had similar scenarios in the past, where somebody is helping a supplier by asking innocent questions that could have been asked by anyone. Like you or BMcF.

I became a little curious on BMcF when he commented like this;

"OK..I actually had seen that site but it's been a while."

The reason is I found the website to be almost new...

But now the air is cleared I hope so let´s go on with the topic.

Lars, I do understand the logic and see how this conclusion was drawn for sure - I guess I haven't been witness to this setup much since you guys are always so on top of them and clean 'em up. I'll leave it alone now - moving on.

[MaxResolution]

Hey, I was really impressed with B-obby McF-aren's 'goading' of SkyDiver, or whatever his name really was. Yes sir-ee, the ocean can be a really unforgiving place.

So, now I know a little more than I did about rolling at sea. And I have to wonder about the trade-offs in efficiency, as we add weight and wet surfaces. Surely this matters less with a larger boat. As to the rear stabalizers I will assume that's most noticable on a faster, smaller boat. 'Passive control' is a sales 'pitch' if I ever heard one.

[BMcF]

Originally Posted by MaxResolution

Yes sir-ee, the ocean can be a really unforgiving place..

Heard that..I took a rather large slug of saltwater in that plow-in..

Originally Posted by MaxResolution

So, now I know a little more than I did about rolling at sea. And I have to wonder about the trade-offs in efficiency, as we add weight and wet surfaces. Surely this matters less with a larger boat. As to the rear stabalizers I will assume that's most noticable on a faster, smaller boat. 'Passive control' is a sales 'pitch' if I ever heard one.

'Passive Control' is largely an oxymoron..I would have to agree with that. However, there are certainly features or devices, bilge keels being one and paravanes another, that can add roll damping 'passively'. The trade-off between roll-damping effectiveness versus added drag (bilge keels and fin stabilizers both add drag, of course) would have to be made in every case. And then there is the 'cost' penalty of having an active solution vice a passive design feature or simple device like a paravane.

'Rear stabilizers' are most often active trim tabs (not the 'Bennett' variety..rather large special-purpose ones), or interceptors, and are not limited to 'smaller boats' by any means. They are often employed on very large vessels. But they are not (or very seldom anyway) used on round-bilge mono hull forms, nor are they used on 'slower' boats, as you correctly noted.

Quite a few larger yachts are being delivered with four roll stablizer fins vice two these days. It's pretty clear that in those examples, the weighting given to motion control performance is higher than weight given to cost and drag penalty factors in the trade space.

I should also note that the added drag from stabilizer fins is not as great as is often assumed..especially for vessels that have lower transit speeds..say in the max-15 knot range. If it were such a large drag penalty, there would not be so many 'players*' in the fin stabilizer market.

* I am not one of those players, BTW.

[kach22i]

I've seen a lot of fins at different places on boat hulls, but all were computer renderings by students or want-to-be designers. I had no idea before this thread that they could be part of a active control system.

I needed the link in question to understand the topic better and learned something from it.