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Post by Deleted on Sept 12, 2008 11:02:27 GMT 10
Hi Glen, Where you sheet to depends really on the wind range you want the sail to go best in. I sheet to a moderate air position as this seems to work best all around for me. When I do this I don't take any mast tip measurements altho I prob should! The important thing is that the measurements provide your sailmaker with the correct luff curve. Interestingly the moderate air sheeting position gives numbers which most closely match the 12kg weight ones. I was going to post a pic showing the light and heavy/moderate setup I take the measurements from but can't figure out how to do it! Link added with files picasaweb.google.com.au/AUSOKDINGHY/ForumFiles#Karl G'day Karl, I appreciate your comments and have found them to be both informative and interesting. I do have one question regarding mast bend and measuring. You state that to provide what you consider is to be the optimum mast bend is to sheet in for 10 - 12 knots of wind, is this because it is in the mid sailing range or is it just a standard that you have stuck to? Do you use a mast tip to transom measurement as well? I ask this as sheeting positions change depending on your size and technique for sailing in such a wind range.
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Post by Glenn AUS 719 on Sept 12, 2008 13:33:28 GMT 10
G'day Karl,
Yes it is a limiting factor with this forum as photos explain a lot. The ole story of a picture is a thousand words. Thanks for your input though.
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Post by Ok Dinghy on Sept 12, 2008 14:21:23 GMT 10
If added a photo link to Karl's post above. To add photo's we would need to pay. If you want to place photo's send them to ausokdinghy@gmail.com
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Post by Deleted on Oct 15, 2008 11:48:05 GMT 10
Karl
I am a Finn sailor but looking at also hopping into an OK and doing some regattas with you guys, particularly while my Finn is in Europe. I see there is not much on the second hand market. Re: new boats, I know that NZ has the Icebreaker hull and Jason King here in Aus does a delf copy? I believe that Icebreakers are epoxy built whereas Jason's are polyester built, both to very good quality?? Are there any appreciable differences (in speed etc) you can comment on...
Re: masts I know that C-Tech has a strong presence in the OK (not so much with the Finn). Given that your masts are about a third of the cost of ours this is pretty attractive in itself. I come in at 96/97 kg.
Does C-Tech operate like Wilke/HIT etc. in providing masts in 5kg intervals i.e. 90-95kg etc? Also how far advanced are they with matching a mast to a person’s weight, or do most of you guys provide your own desired bend numbers and ask them to replicate? If that is the case, if I decide to push ahead with my idea could I speak to you about mast numbers to suit (obviously I know the Finn stuff pretty well in terms of what suits me - I actually prefer a slightly stiffer mast than my weight indicates - but not the OK comparators).
Sail makers?? Built to mast obviously. Am I right in thinking you guys base luff curve on prebent mast to approx 24 kg leech tension measured at 500 mm intervals from tack to head? If not should I speak to you about this as well when the time comes to sails?
I look forward to hearing from you. Thanks in advance Karl
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Post by Deleted on Oct 16, 2008 7:01:26 GMT 10
Hi Mr,
A lot of questions! But no worries. Firstly hulls, both icebreakers and jasons boats are built to high standards. The general feeling is the delfs are more suited to heavier guys . I sail an icebreaker and I'm 90kg, however Gouch at my club who finished 2nd in the 2002 worlds weighs about 98kg and sails an icebreaker very successfully as well. The delfs have fuller bow sections and I reckon are faster reaching particularly when above 12knts when it gets tight. Upwind I prefer the icebreaker with its finer entry. On the flat offs they're about the same. In OKs we do triangle windward leeward courses so reaching speed is important. Looking at your weight you are prob suited to either design. Andre Blasse is THE guy to talk to about Jasons boats.
Secondly masts. C-tech provide masts to both your weight and to your specified bend nos. I specify bend nos to Alex, like you I now like my masts a little stiffer than most people would think right for your weight. I don't know if he has different layups for every 5kg diff in body weight, altho I suspect he doesn't.
Sailmakers, I get my sails exclusively from Greg Wilcox who is now Quantum Potsdam (Germany). I provide him with bend nos taken from stringline measurements made every 500mm with a sail sheeted on. I generally sheet the sail to a moderate (10-12knt, boom about 180mm above the deck at the tack end) setting and then take the measurements, this is prob around 15-20kg of tension I'm guessing. In Aus the Gale sails I reckon look pretty good as well. Over here in NZ Linton sails are also widely used and go well. Overseas UK North and finnish WB Sails are widely used.
If I can help you out more don't hesitate to ask.
Cheers Karl
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Post by Deleted on Oct 17, 2008 9:01:17 GMT 10
thanks very much Karl
did you mean 180 mm above deck at clew end as opposed to tack
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Post by Deleted on Oct 21, 2008 6:49:04 GMT 10
Ahh yeah!
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Post by Sean on Oct 21, 2008 23:26:12 GMT 10
Any thoughts on Botterill hulls Karl? Competitive or outdated? Better for heavier or lighter sailors?
Thanks for any reply.
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Post by Village Idiot on Oct 21, 2008 23:35:05 GMT 10
Andre is the person best placed to answer this question. I doubt Karl has ever sailed one. My view, having sailed one for a few seasons: * fastest hull available upwind * also pretty good downwind in less than 5 knots
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Post by aus729 on Oct 22, 2008 8:53:50 GMT 10
Nothing wrong with the Botterill hull. The only real issue is that most of the boats are over 20 years old, and have had a hard life, so they maybe soft and not on weight. I won 2 Nationals in one, AUS668. Peter Gale won the worlds in one in 1981. They are probably suited to the lighter person, under 85kg, are very fast upwind and in flat water, good on a lake. In waves they can be tricky, but once mastered can we quick on the square run. Unfortunately the mould has been destroyed so there will be no new ones.
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Post by Deleted on Oct 22, 2008 10:07:52 GMT 10
Hi Andre, Don here trying to learn to sail 668. At Sail Sandy I gradually got into somewhat of groove up wind as the regatta went on. ;D One thing I noticed upwind was I really couldn't match it for height: is this hull shape, 3 yr old sail or my lack of my fleet racing in OK's? However downhill I was constantly run down, badly, any ideas as to the tricks I require to learn, % of board up, amount of vang to control the rolling to weather, pump like crazy Look forward to receiving any help FROM ANY ONE. Regards Don "Still No idea" Williams
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Post by Sean on Oct 22, 2008 11:33:14 GMT 10
Thanks for replies. I am looking to get an OK but cant really justify spending a lot of money as I do sail other another class.
From the little I have read though it would appear without a decent carbon mast you would be struggling to find good speed against others.
How old would 668 be now out of curiosity?
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Post by Deleted on Oct 22, 2008 12:24:45 GMT 10
However downhill I was constantly run down, badly, any ideas as to the tricks I require to learn, % of board up, amount of vang to control the rolling to weather, pump like crazy Look forward to receiving any help FROM ANY ONE. Regards Don "Still No idea" Williams Not Andre here obviously, but I did notice that you had a much looser vang than everyone else (it's hard to make the comparison yourself from inside the boat). While it's generally true that tippy is fast, my feeling is that there is a difference between having a loose leach that lets you maneouvre the boat and catch waves (which is fast) vs being so loose that the boat is wobbly and you're constantly having to correct it (not so fast). My take on it (for what it's worth) is that the guys who are really fast downwind are actually very smooth and controlled in the boat. It's not a mad pump-and-rock exercise like the Finn guys tend to do. Also bear in mind that some of the conditions at Sail Sandy were the worst for the big guys going downwind, as planing/surfing was pretty marginal so the light guys plane on the waves and the big guys don't. It's probably the time when weight difference shows up the most, and has little to do with the boat itself. I reckon the amount that you were losing amounts to just a couple of waves. Downwind is all about waves!
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Post by aus729 on Oct 22, 2008 15:57:16 GMT 10
Well said, Daen.
AUS668 was built in 1985. But was one of the first to be built from modern type foam (divinicell), any built after that plus AUS636 were all built similar. It was also built with S-Glass, which had a great strength and stiffness. I looked after it, and when sold a few years ago it still had 3.5kg of correctors, and was still stiff.
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Post by Deleted on Oct 22, 2008 16:08:39 GMT 10
Thanks to both Daen and Andre for the responses. So quickly summing up, a little more vang than what I started the regatta with and for us big guys the aim is to be smooth in those marginal downwind conditions, and more hours on the water.
Ciao
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