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Sailing Downwind

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Post Options Post Options   Quote Wetabix Quote  Post ReplyReply Direct Link To This Post Posted: 11 Mar 20 at 9:00pm
Just spotted the link - thanks very much - I have bought it. If it tells me I have to change my diet, go to a gym or employ a sports psychologist it'll go straight in the bin!
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Post Options Post Options   Quote polc1410 Quote  Post ReplyReply Direct Link To This Post Posted: 11 Mar 20 at 9:29pm
Downwind always known to be slower than a broad reach. If you can do 4kts dead run, you can probably do 5 on broad reach.

If you had a 1nm leg, doing 4kts you will complete in 15 minutes.
Let's say you go 30degrees off the wind angle at 5kts would be less than 14mins if my maths is right
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Rupert View Drop Down
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Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 11 Mar 20 at 9:34pm
On a pond for 100 yards I'd bet on the straight line.
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Post Options Post Options   Quote Wetabix Quote  Post ReplyReply Direct Link To This Post Posted: 11 Mar 20 at 9:59pm
Your maths is correct but there isn't much in it. By sailing 30 deg off DDW you will sail 115% of the distance. If your boat will sail at 120% of its DDW speed then, yes, it is faster to head up. But will it? I guess if it were cut and dried we wouldn't be having this conversation. Nick Craig says 'soak if you can but during your practice sessions experiment with other angles' if I remember correctly
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JimC View Drop Down
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Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 11 Mar 20 at 10:14pm
Thing is 5 or 10 degrees is more than enough to make a difference.
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Post Options Post Options   Quote Oinks Quote  Post ReplyReply Direct Link To This Post Posted: 11 Mar 20 at 10:24pm

Forgetting the asymmetric issues you raised...they're different from a Phantom. And unstayed rigs like Lasers who do the reverse flow. The stays on a Phantom make that difficult. There are 4 reasons for gybing downwind (1) clearing your breeze from other boats (2) tactical (to gain a ROW advantage or escape from somebody elses), (3) to head towards better breeze, and (4) to point more towards the leeward mark (windshifts).Those are the main things. In a busy fleet 1 and 2 might be unavoidable. But when those aren't so much of an issue , 3 (in patchy breeze) and 4 (in a shifty breeze) are what you should always be trying to deal with. But you should always be trying to do 4. To be doing 4 well, there will be a sweet spot, where your sail is generating max drive whilst trying to go as low as possible. That's the struggle, itís a feel thing and will only come from racing your boat frequently. But as others have said, a good thing would be to talk to people who are good at sailing Phantoms. I think there's a few good Phantom sailors on here.

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Post Options Post Options   Quote polc1410 Quote  Post ReplyReply Direct Link To This Post Posted: 11 Mar 20 at 11:15pm
Originally posted by Rupert

On a pond for 100 yards I'd bet on the straight line.


If they can gybe efficiently... the guy who goes 10-15 degrees may be very pleased by your decision ;-)

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Post Options Post Options   Quote polc1410 Quote  Post ReplyReply Direct Link To This Post Posted: 11 Mar 20 at 11:26pm
Originally posted by Wetabix

Your maths is correct but there isn't much in it. By sailing 30 deg off DDW you will sail 115% of the distance. If your boat will sail at 120% of its DDW speed then, yes, it is faster to head up. But will it? I guess if it were cut and dried we wouldn't be having this conversation. Nick Craig says 'soak if you can but during your practice sessions experiment with other angles' if I remember correctly


Pretty sure this is the art of racing. Knowing do you go 5, 10, 15, 29, 30 degrees for the conditions. Plus Reading the shifts and the conditions.

You only need to get a boat length ahead for things to matter.

My example was picked for simplicity of maths.

Polar plot from a Volvo Ocean 60


Not the perecntage difference changes by wind speed.

Not sure what matters?

Get three identical boats to round a windward mark in quick succession. Boat 1 - dead down wind. Boat 2 - 10degree, Boat 3 - 30 degree...

Who hits the downwind mark first...?

This is why good racers practice. They are testing different approaches
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Post Options Post Options   Quote Sam.Spoons Quote  Post ReplyReply Direct Link To This Post Posted: 11 Mar 20 at 11:45pm
Originally posted by polc1410

Get three identical boats to round a windward mark in quick succession. Boat 1 - dead down wind. Boat 2 - 10degree, Boat 3 - 30 degree...

Who hits the downwind mark first...? 

Depends on wind strength, assuming nobody is blanketing anybody else.
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Rupert View Drop Down
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Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 12 Mar 20 at 8:40am
Originally posted by polc1410

Originally posted by Rupert

On a pond for 100 yards I'd bet on the straight line.


If they can gybe efficiently... the guy who goes 10-15 degrees may be very pleased by your decision ;-)



Maybe, and sometimes I'll bet against, with, as you'd expect, mixed results, some good, some bad.

But putting this into a racing situation means my decision to go off course will be influenced by everything others have said. If someone is sailing angles, I may decide to cover and keep clear wind. If on my own, then the choice is DDW or 5 degrees off to create flow, depending upon wind strength, where the trees are, etc, as JimC says.

But I sail short, slow boats, so the speed gains are limited, especially in non planing conditions.

Volvo 60s they are not.
Firefly 2324, Lightning 130, Puffin 229, Minisail 3446
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