| Re: Downwind techniques
[Re: ucfsailor19]
#146783 06/25/08 04:15 PM 06/25/08 04:15 PM |
Joined: Jan 2005 Posts: 829 Charleston, SC NCSUtrey
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old hand
Joined: Jan 2005
Posts: 829 Charleston, SC | It has to do with apparent wind. If you are on a beam reach and your sails are trimmed properly, the wind vane will be angled less than 90 degrees, more like 45 or 55 degrees. You have to picture the boat as it's moving. Both the wind from behind you and the wind created by moving forward work together to move the vane to 90 degrees.
Trey
| | | Re: Downwind techniques
[Re: ucfsailor19]
#146784 06/25/08 04:41 PM 06/25/08 04:41 PM |
Joined: Feb 2004 Posts: 3,528 Looking for a Job, I got credi... scooby_simon Hull Flying, Snow Sliding.... |
Hull Flying, Snow Sliding....
Carpal Tunnel
Joined: Feb 2004
Posts: 3,528 Looking for a Job, I got credi... | Hey guys,
I recently picked up Rick White's Cat Sailing for the 90's... I got to downwind section, don't remember the page number, but he talks about two methods of sailing downwind. The first being set the sails for the course and then steer to keep the tell tales going. The second was keep the bridle wind vane 90 degrees to the boat and adjust the sails. The thing I don't get is how is the second method different, if you keep the boat 90 degrees to the wind then your sails shouldn't need to be adjusted right, you are just staying on a beam reach which is what the first method is. I know i'm missing something, been a great book so far. Consider walking around a carpark.... Wind is North at exactly 1mph. Stand in the middle of the car park. Where is the wind coming from ? Answer - N at 1mph Now walk south at exactly 1mph - where is the wind - nowhere, you are walking in the same direction as the wind at the same speed. You feel NO wind. Now turn around and wak directly INTO the wind at 1mph. where is the wind ? in your face at 2mph Now turn east and walk at 1mph, now where is the wind? well it's now coing from NE as you have a VECTOR of the true wind (N) plus 1mph east (your walking speed) and the wind you will feel is root(2) 1.41mph. now turn southeast and walk at 1mph, again the wind you FEEL will be shifted as a function of the fact you are walking at an angle to the wind, the faster you walk, the more the apparent wind will go east. now do the same on your boat. Sailing southeast in a North wind, as you speed up, the VECTOR changes and the wind moves east, the more you either 1, Sheet in 2, Bear off to keep the apparent wind at the same angle.... Faster you go, more sheeting in, or more bear off....
F16 - GBR 553 - SOLD I also talk sport here | | | Re: Downwind techniques
[Re: NCSUtrey]
#146785 06/25/08 05:06 PM 06/25/08 05:06 PM |
Joined: Dec 2005 Posts: 321 Albuquerque NM Banzilla
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Posts: 321 Albuquerque NM | It has to do with apparent wind. If you are on a beam reach and your sails are trimmed properly, the wind vane will be angled less than 90 degrees, more like 45 or 55 degrees. You have to picture the boat as it's moving. Both the wind from behind you and the wind created by moving forward work together to move the vane to 90 degrees. This is the toughest part of sailing for me so, 1)I understand a Beam Reach as going 90 to the wind. There would not be wind from behind Question: Is that true wind or apparent wind? (Assuming constant winds) If it is true wind, than once you are at max speed, sails are set and your just crusing right? If a beam reach is 90 to the apparent wind, wouldn't you just keep going in circles? As the apparent wind changes you have to change course to stay 90 to it <img src="http://www.catsailor.com/forums/images/graemlins/tongue.gif" alt="" />
[b] Sail Like you have a Pair
| | | Re: Downwind techniques
[Re: Banzilla]
#146786 06/25/08 06:05 PM 06/25/08 06:05 PM |
Joined: Feb 2004 Posts: 3,528 Looking for a Job, I got credi... scooby_simon Hull Flying, Snow Sliding.... |
Hull Flying, Snow Sliding....
Carpal Tunnel
Joined: Feb 2004
Posts: 3,528 Looking for a Job, I got credi... | 1)I understand a Beam Reach as going 90 to the wind. There would not be wind from behind
Question: Is that true wind or apparent wind?
(Assuming constant winds) If it is true wind, than once you are at max speed, sails are set and your just crusing right?
If a beam reach is 90 to the apparent wind, wouldn't you just keep going in circles? As the apparent wind changes you have to change course to stay 90 to it <img src="http://www.catsailor.com/forums/images/graemlins/tongue.gif" alt="" />
Beam reach is defined as 90 to TRUE. No, you will not go in circles as, as you bear off, the appaernt moves back ast, yes you MIGHT continute to accelerate and so the apparent mores forwards again, but you cannot keep on bearing off and keep accelerating; at some point friction overtakes you and you cannot bear off any more.
F16 - GBR 553 - SOLD I also talk sport here | | | Re: Downwind techniques
[Re: ucfsailor19]
#146790 06/26/08 10:02 AM 06/26/08 10:02 AM |
Joined: Mar 2005 Posts: 160 claus
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Posts: 160 | The 90 degrees rule applies to the Hobie 16, I don't know about other cats. On the downwind leg we go with 90 degree of apparent wind, then set the jib accordingly (in lighter wind the crew has to hold the tack with the hand in order to induce more bend in the battens) and now we steer by the jib telltales (never ever stall). If we note we are going higher than 90 degrees with the lee telltales just before stall, the jib as to go out more. So it really is a combination of the two. Remember, the jib is it all for going downwind.
Last edited by claus; 06/26/08 10:06 AM.
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