Polars, PHRF, boat speed, boat shopping - Page 2 - SailNet Community
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post #11 of 55 Old 02-13-2011
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Originally Posted by hellosailor View Post
But don't expect the guys who are in the business strictly to make a profit, to make your life easy. They'd rather sell you the wrong boat four or five times than sell you just one. There's no money to be made in selling just one.
Sure there is, but there's a lot more in selling four or five boats.

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post #12 of 55 Old 02-13-2011
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define trailerable? Retracting keel is what will make all the difference. And how fast do you want it? Got a PHRF # for your 'dream boat'?

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post #13 of 55 Old 02-13-2011 Thread Starter
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Yah, a Hobie 33 with a raised cabin roof, but also too expensive. My point reference was the Beneteau 235, which has a PHRF around 200 depending on who you ask. The only reason it is a point of reference is because the do publish polars for their boats, so I at least know what to expect. I surely would not want anything higher/slower than that. After seeing some of these trimarans, I struggle to keep looking at monohulls, but that is where my budget is.

Trailerable to me means 8.5' wide, and can be put in without a crane. Weight is not much of an issue, although typically that would make the boat slower. I would target somewhat of a length limitation, because I would expect to tow it behind a 31 foot motorhome. 65' total is the max length for towing. Longer would not totally rule out anything, as I can always tow it with the Jeep if I had to.

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Sailing a large boat on a small lake is very tacky.

Last edited by Daveinet; 02-13-2011 at 10:33 PM.
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post #14 of 55 Old 02-14-2011
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Melges 24 PHRF 81
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post #15 of 55 Old 02-14-2011
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I guess you missed the part about under 10k.

Try the Fun 23
FUN 23 Sailboat details on sailboatdata.com

Dave, the total tow length need to be under 61'? How does the mast measure in that computation?

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post #16 of 55 Old 02-14-2011
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Quote:
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Most people don't care all that much. If the opening shot in an advertisement is a boat's interior--common to Hunter's--performance isn't the selling point. Some class and owner's associations compile Polars.



Yes
Another reason why the information that you are referring to is not often made available is that the publications that would be likely candidates to publish it depend on advertising from those manufacturers to continue to exist. Not just performance information -- when was the last time you read a really poor review of a boat in a sailing or yachting magazine?
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Quote:
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I guess you missed the part about under 10k.

Try the Fun 23
FUN 23 Sailboat details on sailboatdata.com

Dave, the total tow length need to be under 65'? How does the mast measure in that computation?
The mast could probably go above the back of the motorhome if need be, the motorhome is low profile, so plenty of height above it. Trailer length from ball to the motor should be under 33 feet, although if the motor weighs less than 100 lbs, I could always pull it off. I've never heard of anyone getting pulled over for exceeding maximum length in a motorhome + trailer, but I should try to be close enough that no one would bother me.

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...Not just performance information -- when was the last time you read a really poor review of a boat in a sailing or yachting magazine?
I read a review of the Imus power sailor. The comment in the review just causally mentioned they had a wind of 8 knots and were sailing along at around 4 knots, which they thought that was very good. Good or not, they got away with making the statement. As long as it is contextualized as a positive, they should be able to get away with it. Bike and car magazines give zero to sixty times. Of course that caused the bikes to get very competitive.

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Sailing a large boat on a small lake is very tacky.
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post #18 of 55 Old 02-14-2011
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In other words, I could afford more, but for something that only I enjoy, it should not consume that high of a % of available funds.
Souds like a resonable way to think about it, but I use a different formula.

Amt_to_spend_on_boat = ((available_funds * 15%) / (wifes_opposition - husbands_nagging_tolerance_factor))

But then math was never my strong point.

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post #19 of 55 Old 02-14-2011
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You'll be limited a bit with a mast height of 30' unless you put it on the motor home. The outboard shouldnt' weigh in more than 60 lbs and you don't want to trailer it with the motor on the back anyway. Throws the weight off, especially on small boats.

You still haven't given an explaination on what you define as "fast". Are we talking Colgate 26 'fast' at 156 PHRF, or are we talking TP52 fast at -87? Or are you talking as fast as you can get for 10k? Define your limiting factors better and we can help you more.

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post #20 of 55 Old 02-14-2011
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And what are you going to use this boat for? You mention you want a cabin with full sitting headroom. Some of the really fast boats won't have that.

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About the only rating common to most boats for comparison purposes has been PHRF, which seams to give some indication of performance but not much.
PHRF numbers are given time differences in seconds per mile with the base boat apparently being the 12-meters once used to race for the America's Cup (e.g. that's "0"). In other words, a boat that has a PHRF rating of 180 would be about 3 minutes per mile slower than a 12, on average. Of course, there are a lot of problems with single number rating systems like this - are we talking upwind, downwind, on a reach; strong wind, light wind, or nice moderate breeze. In addition, the system really doesn't work well at quantitative comparison across wide ranges. E.G. we know a 0-rater will be a lot faster than a 180-rater, but will it really be exactly 3 minutes per mile? The system works better for comparing boats that are more similar to each other.

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SA/D doesn't seam to tell you much, as my current boat has a pretty good SA/D ratio, but is still pretty slow, even in light winds.
What do you define as a "good" SA/D ratio?

What you really want is a ratio of sail area to wetted surface area, unfortunatley few people really know the wetted surface area quantitatively. Qualitative comparisons are relatively easy, though.

But there are other factors besides just sail area, like rig height, that are also important.

Other than having an opportunity to sail on a bunch of different boats in different conditions, I think PHRF numbers are probably going to be the next best way to get a sense of the relative performance of a selection of boats. In other words, look for boats that meet your criteria: under 10K, fit on trailer, launchable without a hoist, cabin with sitting headroom, and then you can start to filter your list by PHRF....

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Last edited by catamount; 02-14-2011 at 03:19 PM.
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