There are few more things about scaling. Most of them play with the forces:
1) Whatever you sail the forces must be such that you can handle them. Things that work fine in small scale may create forces that make it unusable in bigger scale. Structural issues also follow from the same.
2) If your model capsizes that is no issue. If your dinghy capsizes you right it and continue. If you capsize a 15 m multi with your family on board that is a BIG issue. Therefore fast depowering and other solutions that make the boat safer are more important in big scale than on models and dinghies. Luckily size also brings more stability.
3) Ease of use makes boat more comfortable and sails will be used more if they are easy to set and douse even in a hurry and without any helping hands.
4) For many if not most having time to sail means taking family with you. Sailing with the family you often find yourself sailing together with only autopilot to help you. Arranging a boat in a way that allows true singlehanded sailing is a BIG bonus.
So the point is: model testing helps in many ways but it has its limitations. In choosing the rig for me performance is one aspect but the handling alone with the force I can comfortably get out of my muscles fast enough is the first limiting factor that may rule out some options. Fast depowering when needed is a must. After that comes other considerations like performance, shunting speed etc.
Arto
Remembering how fast one can pull down the main in a real hurry when thunder clouds bring sudden strong gusts that double the boat speed in seconds...
From: Roger L <rogerlov@ix.netcom.com>
To: harryproa@yahoogroups.com.au
Sent: Monday, September 26, 2011 7:12 PM
Subject: Re: [harryproa] Re: Bow down trim - or bow up trim
To: harryproa@yahoogroups.com.au
Sent: Monday, September 26, 2011 7:12 PM
Subject: Re: [harryproa] Re: Bow down trim - or bow up trim
<"To you and many other I'm just ignorant due to my lack of education."
No problem there. Everyone lacking education is ignorant of whatever it is that they aren't educated it. It's not a fault, and its an easy enough situation to remedy....and then to get credit for your work. But it's not so easy to convince others that book knowledge isn't valuable. If a subject interests you, go do the work to learn what others already know about it. Until then you're guessing. That's fun, but no more than that. Certainly not worth yelling about. And it doesn't get a boat built.
BTW, you are correct; there's a certain amount of interpretation in modeling. But assumptions aren't the same as guesswork. There's a baseline of knowledge implied. That baseline is what allows folks to share their work.
You sound like an intelligent guy, so why not go get some learning? Or as you put it, piss or get off the pot.
Roger L.
Apparently, Modeling is the interpretation of finding modelers own answer to a theory. To you and many other I'm just ignorant due to my lack of education. You, they will always cast that shadow on me its easiest way to discredit.
Lets see some of your work and others on here. Where is it why are all you hiding there work. I bring forth my experiences and share my knowledge good or bad where's yours?
What I'm saying if splitting hairs over a few centimeters here and there without even building a model of any size why bother. Whats the point? PISS OR GET OFF THE POT...
I shouldn't have said anything....You'd like that huh
tODD
--- In harryproa@yahoogroups.com.au, "Roger L" <rogerlov@...> wrote:
>
> Tsstproa, I agree and think you are on to something there, but the reason isn't simple. Although the numbers that are put into analysis are right and so are the answers......the truth is that the real world contains more variables than anyone can reasonably put in. We agree on that.
>
> I'm sure the guys in Top Gear know that and are just making that same point. I doubt that they are ignorant of the limitations of analysis or so full of themselves that they think if one car looks better than another on some limited paper analysis that it will perform better overall. I'm guessing that's not what they are trying to say. After all, it would be just plain uneducated thinking leading to a wrong conclusion......somehow the Top Gun guys don't seem that dumb to me.
>
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