Heeling to windward when sailing downwind

Moderator: GreenLake

Heeling to windward when sailing downwind

Postby holstein » Fri Dec 16, 2011 9:20 pm

In this racing video, and when I've watched sunfish race, I've watched them heel their boats to windward when sailing down wind.

http://www.youtube.com/watch?v=SXmd_9Qi ... ture=share

What is the advantage of doing this, and does it apply to the DS ??

Bill H
holstein
 
Posts: 53
Joined: Mon Jan 17, 2011 10:34 pm

Time stamp

Postby holstein » Fri Dec 16, 2011 9:32 pm

Start watching the video at 14:00 minutes.

Bill H
holstein
 
Posts: 53
Joined: Mon Jan 17, 2011 10:34 pm

Postby Scott Mulford » Sat Dec 17, 2011 12:04 am

It is to decrease rudder drag caused by a weather helm.

Downwind the center of lateral resistance (CLR) is the hull centerline. The center of effort (CE) is in the middle of the sail area. During level sailing the CE and CLR are offset adding a turning moment to windward which has to be corrected with the rudder.

Heeling to windward lines the CLR and CE up one over the other so you don't have to add a rudder input (drag) to correct the force turning you to windward.
Scott Mulford
 
Posts: 42
Joined: Fri Aug 12, 2011 6:48 pm

Postby K.C. Walker » Sat Dec 17, 2011 9:45 am

+1 for what Scott said. Also, you reduce drag by reducing the whetted surface. By rolling the boat up off of the flat bottom and on to a narrower, more canoe shaped, part of the hull.
KC Walker, DS 1 #7002
K.C. Walker
 
Posts: 1335
Joined: Sun Jul 06, 2008 10:50 pm
Location: North Stonington, Connecticut

Postby Mike Gillum » Sun Dec 18, 2011 9:11 pm

Growing up in Southern California and even today I've sailed everything I've raced heeled to weather downwind except in really light air.
After five years racing the Day Sailer I'm still not sure if there's any benefit to heeling it to windward on the run.
I have a tendency to heel the Day Sailer to leeward most of the time as I'm also sitting to leeward trimming the Jib allowing my wife Mardi to be on the windward side to effectively trim the Spinnaker.
KC is correct that by heeling the Day Sailer you decrease the wetted surface area by submerging the side of the hull and putting the leeward half of the hull up in the air.
The other theory heeled to weather is that you also push the Main's center of effort higher in the air grabbing more wind and that means you don't want to ease your outhaul on the run either to keep the center of effort further out on the boom and higher in the air.
Heeled to weather in the other one design classes allows me to see the waves better and in most cases I'll use my weight and the boomvang to steer the boat rather than the tiller as any movement of the rudder will slow down the boat.
To head down I'll hike outboard and ease the boomvang and to head up I'll lean inboard and tighten the boomvang. In both cases I'm trying not to move the hiking stick reducing any drag the rudder will create.
Probably the most important thing offwind in the Day Sailer is fore/aft weight placement as well as proper sail trim of all three sails.
Seated to leeward I have a better view looking up at the masthead fly to determine what shifts are coming downwind as well as being able to look slightly aft to see any puffs coming towards us.
Most people incorrectly assume the run is a time to relax but in reality its probably the single best place to either pass your competitors or increase your lead if you're going fast and can use the shifts to your advantage.
Mike Gillum
 
Posts: 163
Joined: Wed Jul 26, 2006 7:28 pm
Location: Loomis, California

Postby K.C. Walker » Wed Dec 21, 2011 11:51 am

Mike,

Thanks for your description and techniques! I do wish that winter wasn't upon us here in New England. I really would love to go tryout/practice steering with the boom vang, it's something I hadn't thought of.

It's probably not appropriate to a Daysailer, but have you any thoughts on reverse flow on the main while running?
KC Walker, DS 1 #7002
K.C. Walker
 
Posts: 1335
Joined: Sun Jul 06, 2008 10:50 pm
Location: North Stonington, Connecticut

Postby Mike Gillum » Wed Dec 21, 2011 12:43 pm

Hard to get reverse flow on either the Day Sailer or Thistle mains as both have shrouds set well aft of the mast that doesn't allow the main to even get close to 80 degrees out from centerline.
You can ease the boomvang off to twist the main around the shroud but that cause a capsize in the right conditions so a gybe is usually a better and safer answer.
In the Day Sailer we're also flying the jib while running so anytime you get by the lee the jib starts to act like a spoiled child demanding attention.
At 2011 DS NAC's the "light bulb" finally went on in my dimly lit brain when I realized that the jib was telling me when I transitioned from a broad reach to DDW (Dead Down Wind) when it went flying properly to hanging lifelessly.
The transition from DDW to by the lee was the jib going from hanging lifelessly behind the main to the jib fighting to get around the mast to windward.
Sometimes that sequence happened more than once as our apparent wind and direction of #2772 changed repaetedly as we surfed DDW in the heavier air races but in the light to moderate conditions I became very aware of what the jib was "telling" me in relation to what my course was and what I wanted to do tactically in regards to my competitors and course management.
In a Laser you can easily and effectively reverse the flow over it's main. Its really amazing to be sailing by the lee while planing on a Laser with the main at or just past perpendicular to centerline and the centerboard all the way down while leaning hard to leeward to keep from capsizing to windward then immediately head up 30-60 degrees and then hiking to windward to keep from capsizing to leeward as you continue to plane to either stay on the same wave or grab the next wave in front of you.
Most of the Laser "kids" have figured it out and they're breathtaking to watch as they work both their Laser and waves to plane around us "Masters" on the runs while we only get lucky from time to time.
Thank god most of them haven't figured out how to work shifts or course management yet allowing us to beat them with old age and treachery!
Mike Gillum
 
Posts: 163
Joined: Wed Jul 26, 2006 7:28 pm
Location: Loomis, California

Postby K.C. Walker » Thu Dec 22, 2011 10:31 am

The old age masters of treachery, I like it! :-)

I'd been reading about reverse flow Re: Lasers so I thought maybe a single sail boat might be where it was appropriate. I didn't think about it needing to be also an unstayed mast. Thanks for sharing your aha moment regarding using the jib itself as a indicator. It makes perfect sense now that you point it out.
KC Walker, DS 1 #7002
K.C. Walker
 
Posts: 1335
Joined: Sun Jul 06, 2008 10:50 pm
Location: North Stonington, Connecticut


Return to Racing/Performance

Who is online

Users browsing this forum: No registered users and 2 guests

cron