How does Chine affect sailing?

[Ceawolf]

yesyerday I looked at a Flicka and saw a west wight potter,, both the right size for me now but what ddo you old salts say about the performance? or is this like asking what chocolate tastes like?

[boatman61]

Chine is good...

[Orion Jim]

For a given size chine will usually result in increased useful space. Flat hull sections can pound and presenting a broadside flat surface to a large sea does not allow it to gently alter its direction

[GordMay]

An earlier discussion (2005):
➥ http://www.cruisersforum.com/forums/...ound-2621.html

[denverd0n]

Chine is just one element of boat design. A boat's performance is a function of how all of the different design elements work together. You cannot just look at "chine" or "no chine" and expect to tell anything about the boats overall performance.

And then, of course, there is the question of what the word "performance" means to you. Are you talking about performance on a lake with moderate winds? Performance far offshore in heavy weather? Something completely different? These are all different sorts of "performance."

The Flicka has a displacement that is four and a half times as much as the Potter (assuming you're talking about a Potter 19). Heck! The Flicka's ballast alone is 37% more than the total displacement of the Potter. The Potter's SA/D ratio is almost 18.5 while the Flicka's is less than 13. Their respective D/L ratios are 116 for the Potter and over 400 for the Flicka.

These are dramatically different kinds of boats. The Potter is going to run away from the Flicka in any sort of light-air condition, and in fact in most sailing conditions. The Flicka is going to sail far more comfortably in anything resembling heavy weather, not to mention that it has the carrying capacity for much, much longer cruises.

So the bottom line is that there really is no comparison between these boats. If you are trying to understand the difference that a chine makes in a boats design, you really need to compare two boats that are fairly similar in other regards--where chine vs. no chine is the main difference between them. With these two boats that is just not at all the case.

[Ceawolf]

Fair enough, of course I am asking to learn as a complete newbie, and feel like I am in the wrong room among learned sailing engineers and physicists. I guess leaning over the side to look at a fish or something is easier on a hard chine.

[denverd0n]

Originally Posted by Ceawolf

Fair enough, of course I am asking to learn as a complete newbie, and feel like I am in the wrong room among learned sailing engineers and physicists.

You're not in the wrong room. I hope you didn't take my comments as criticism of you. I'm just trying to help. The point is that--as a complete newbie--there will probably be times when you will ask a question to which the best answer is, "you're asking the wrong question." This is one of those times. That's all.

In fact, a comparison between the Flicka and the Potter can be quite instructive, specifically because they are such dramatically different boats. Both have similar lengths and beams, but that is pretty much where the comparison ends. They are so very different in every other aspect that they are a perfect example of why you cannot look at just one or two design elements and make a meaningful comparison between boats.

Good luck to you.

[Blue Stocking]

Originally Posted by denverd0n

Chine is just one element of boat design. A boat's performance is a function of how all of the different design elements work together. You cannot just look at "chine" or "no chine" and expect to tell anything about the boats overall performance.

And then, of course, there is the question of what the word "performance" means to you. Are you talking about performance on a lake with moderate winds? Performance far offshore in heavy weather? Something completely different? These are all different sorts of "performance."

The Flicka has a displacement that is four and a half times as much as the Potter (assuming you're talking about a Potter 19). Heck! The Flicka's ballast alone is 37% more than the total displacement of the Potter. The Potter's SA/D ratio is almost 18.5 while the Flicka's is less than 13. Their respective D/L ratios are 116 for the Potter and over 400 for the Flicka.

These are dramatically different kinds of boats. The Potter is going to run away from the Flicka in any sort of light-air condition, and in fact in most sailing conditions. The Flicka is going to sail far more comfortably in anything resembling heavy weather, not to mention that it has the carrying capacity for much, much longer cruises.

So the bottom line is that there really is no comparison between these boats. If you are trying to understand the difference that a chine makes in a boats design, you really need to compare two boats that are fairly similar in other regards--where chine vs. no chine is the main difference between them. With these two boats that is just not at all the case.

Excellently put

[Garrettw]

Not necessarily related to performance, but still germane to the topic of chines, I have found that the flat-ish bottom of my hull created by the chine causes an interminable slapping sound when at anchor or at the dock, in anything other than calm water. I don't think that would be a problem aboard the Potter because the stern is submerged, but in newer boats with a bit of overhang and a flat bottom afforded by chines, it's an issue of comfort.

[Ceawolf]

I appreciate your willingness to talk about this, what is SA/D ratio? sail area to displacement? and D/L ratio? displacement to length? how can I understand what the ratios mean to the sailor? How do chine and other factors relate to displacement and ballast?
I enjoy the discussion, hope others do as well. Books lack that personal touch.

[denverd0n]

Well, this does kind of get into the engineering and physics of it, but is an excellent explanation of some of the key factors that affect boat design, written by one of today's premier naval architects.

Ted Brewer Yacht Design