The Physics of Railmeat - Page 5 - SailNet Community
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post #41 of 51 Old 12-21-2010
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Andre

Do you mean canting keel?
If that's what you prefer, yes.


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post #42 of 51 Old 12-21-2010
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If that's what you prefer, yes.
I am not much of a swinger.

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post #43 of 51 Old 01-07-2011
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You do have my number, right?
You crack me (and apparently, your glasses) up Smackdaddy! And "railmeat" is still two words bytheway!
On a serious note - nice response Jeff.
Why does the AC crew in my Avatar have their legs inboard (click on it to enlarge). Is hiking not allowed in AC? Not that it matters now that they are going to 73 foot cats in SAN FRANCISCO...YIPPEEE!
Sorry...I digress. Why no hiking?

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post #44 of 51 Old 01-07-2011 Thread Starter
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You crack me (and apparently, your glasses) up Smackdaddy! And "railmeat" is still two words bytheway!
On a serious note - nice response Jeff.
Why does the AC crew in my Avatar have their legs inboard (click on it to enlarge). Is hiking not allowed in AC? Not that it matters now that they are going to 73 foot cats in SAN FRANCISCO...YIPPEEE!
Sorry...I digress. Why no hiking?
Hiking comes off as a bit too desperate for true gentlemen.
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post #45 of 51 Old 01-07-2011
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Hiking comes off as a bit too desperate for true gentlemen.
So does duking it out in court...but that never seems to stop them!
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post #46 of 51 Old 01-07-2011 Thread Starter
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So does duking it out in court...but that never seems to stop them!
Touch!

I'd have a little respect for those chumps had they raced in whatever conditions there were at race time.

That's why I'm a VOR man. THAT'S freakin' yacht racing.
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post #47 of 51 Old 01-07-2011
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Isn't it fair to say that crew placed to windward are having less of a negative impact on heel than crew placed to leeward. Crew placed to leeward would have a greater lever, but working against you? They may or may not have a positive affect to windward, but ultimately, you are eliminating as much of the negative affect as you can.
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post #48 of 51 Old 01-07-2011
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Why does the AC crew in my Avatar have their legs inboard (click on it to enlarge). Is hiking not allowed in AC? Why no hiking?
Could be a rule, but those AC boats also didn't have life lines, just a grab rail foreward for the bowman. I still remember seeing people hike, but they would lay lengthwise on the edge with one leg in one leg out to hike.

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post #49 of 51 Old 01-07-2011 Thread Starter
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Okay, I may have to call BS on Jeff. Here's an article I was turned onto at SailingWorld by a really cool dude that was banned here:

Harder Hiking for Better Results

And here's a section that basically says I'm a freakin' genius:

Quote:
Many people overlook the importance of hiking when a boat is almost flat; however, this, we discovered, is when the hiking action is most effective. As heel increases, a smaller percentage of a sailor's weight is directed perpendicular to the lever arm, which decreases the sailor's effect on the boat's righting moment. In other words, it may be more effective to depower the sails to flatten the boat than to have the entire crew exhausting themselves.
So, Jeff, I think you need to duke it out with John Loe And Val Smith. I'll hold your jacket while you work your abacus. Heh-heh.

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post #50 of 51 Old 01-08-2011
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Taking Sailing World's comments in the context of the article, and my comments in the context of this discussion, I would suggest that we actually are more in agreement than not. I would also suggest that any apparent discrepancy between the Sailing World quote and the discussion above is a more about these not being nuanced discussions than being any disagreement.

As I read the quote from Sailing World, it is saying that as a boat heels the center of gravity of the crews weight shifts closer to the center line of the boat, and therefore is less effective than when the boat is flat. If I consider that point taken isolation, I have no disagreement with that. What it does not discuss, and which is outside the scope of the article, is that as most modern boats heel, the center of buoyancy moves to leeward and so although the center of gravity of the crew weight moves toward the centerline, the impact on righting moment may actually stay the same or increase up to some point of heeling angle.

At some angle of heel, the center of buoyancy begins moving back toward the center of gravity of the crew and so the crew's impact drops considerably.

I also completely agree with their statement, "In other words, it may be more effective to depower the sails to flatten the boat than to have the entire crew exhausting themselves."

Allowing a boat to heel potentially has a series of negative effects on performance (increased leeway, increased weather helm (and so more drag from steering to counter act), larger tip vortexes on the underwater foils and so on.). To some extent, these negatives are at least in part offset by having more drive from the sails. Up to a point, this greater drive results in better performance by overcoming the greater drag and leeway from heeling. But after that point, performance drops off as the amount of drive ceases to increase but drag continues to increase.

What the Sailing World sentence is saying is that instead of over-powering-up the boat and having your crew wear themselves out hiking, you may actually have better performance by depowering some and sailing flatter. The key word in the Sailing World quote is the word "may", which I marked in bold for emphasis, since it will be up to the skipper and crew to find that point and stay at or near it as much of the time as they can. If the boat spends a bunch of time way above or below that heel angle relative to their competition, they will end up reading a whole bunch of hailing ports.

It does not take a genius to see that, but somehow you missed it.

Jeff


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Last edited by Jeff_H; 01-08-2011 at 06:37 PM.
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