Beating angles Beneteau 411

[dkobyrne]

Hi,

I have a Beneteau 411 celebration and would appreciate advise/direction on rig tuning and sail trim for effective beating upwind. I need to tune instruments but when beating upwind I have a readout of apparent angle of about 30 degrees on each tack. The track feature on the chartplotter tells me that I am tacking through about 100-110 degrees going upwind. That is, I am making a true upwind speed of about half or less than half of my boat speed (notwithstanding tide and wind effects). What should I expect to achieve and am disappointed with that performance to date ?

Any help appreciated.

Declan

 

[Cayennita]

30 degrees true or apparent? Are you out of phase with wind shifts. For example with a 10 degree oscillation you could be tacking in a 100 or an 80 degree angle. Do you have a VMG instrument?
You can find a rig tuning guide on line by Googling. Keel depth is proportional to the ability to go to windward. If yours is a shallow drat keel, you might be pointing too high and stalling the keel. Might need to snake wake the boat.

 

[Alan]

Here is a polar for the 411. Do you have a TV antenna at masthead? a ray dome half way up? furling headsail? three blade prop? all these will affect your pointing ability

http://www.intersessions.com/411/411polars.html

 

[Seattle Scott]

"the chartplotter tells me that I am tacking through about 100-110 degrees going upwind."

Keep in mind tha tthe chartploter tells you where the boat is going, not where it is headed or pointed, so add 5 degree or so for leeway on each tack, so figure 90-100 degree tacks relative the wind and 100-110 degrees on the chartplotter.

Make sense?

 

[Joe]

I would approach your task a bit differently... you need to measure against true wind rather than apparent. The apparent wind angle will change with boat speed and wind velocity. Sail on opposite tacks, then take an average of the headings... that is your true wind heading... the total degrees between tacks, divided by 2, is your tack angle. Compile 3 sets of data for light, medium and heavy air...

You can use your magnetic compass for true wind direction magnetic, or the gps for true wind direction true

 

[Stu Jackson]

"the chartplotter tells me that I am tacking through about 100-110 degrees going upwind."

Keep in mind tha tthe chartploter tells you where the boat is going, not where it is headed or pointed, so add 5 degree or so for leeway on each tack, so figure 90-100 degree tacks relative the wind and 100-110 degrees on the chartplotter.

Make sense?

Not necessarily. If he's using TRACKS, then he should be able to figure it out if he'd recorded the true (or mag) wind direction. Simple plotting with a track.

 

[RichH]

By trigonometry a 30 degree apparent angle will result in 87% of your forward speed component in the desired direction ..... so that isnt the problem (50%). So, you're probably skidding off to leeward, sails trimmed in tooooo hard, or are severely pinching. 100-110 degree tack angle indicates a 'skid' to leeward and a skid will show up with the wake coming off the stern at a noticeable angle - not straight, plus the helm will feel like 'weather helm' ( but it isnt).

Suggest you first tune the rigging so that at least the forestay (backstay) is at at least 15%+ tension, then follow the directions in Don's Guilettes "SailTrim Users Guide" (obtainable by clicking on the link at the top of this page).

then once you master the basics in that above basic booklet, then for precise pointing:
www.arvelgentry.com --->magazine articles----> the following 'series' of articles:
Checking Trim on the Wind, November 1973
Achieving Proper Balance, December 1973
Sailing to Windward, January 1974
Are You at Optimum Trim?, March 1974

After you arrive at **correct rig tension**, a boat wont 'point' unless all factors of sail *shape* and trim are at optimum for the conditions you are sailing in. You'll need a *complete/full* set of tell tales (luff/midcord/leech... plus a row of 'steering tell tales' on the jib/genoa) to do this to keep the boat precisely 'in the groove' and at a very precise angle of attack.

If you have a roller furling mainsail you will have to adjust the amount of furl so that the boat doesnt have any excess weather helm due to the mainsail shape. On non-furled main, you can easily adjust the luff tension (by halyard tension) to get close to a 'neutral helm' (but one that provides a 'slow heading up' when the wheel is released, during the basic set up for each day's conditions.

 

[dkobyrne]

Cheers for the replies and additional comments :

yes the 30 is apparent and have deep 2 m keel. My instruments need recalib as some problems but 30 deg also ties in with bracket on windvane at top mast.

Do have radome, antenna, furling genoa but a folding prop and agree all has impact

Chartplotter track is gps over the ground and yes impacted by leeway and tide and maybe shifts but consistant over many examples of angle greater than 100 deg which may be OK but a long beat !

Yes should try and compile true angle various means under different wind strengths

Yes not getting great angle and did not detect significant leeway off wake and not pinching as when do lose a knot. Generally very little weather helm. Will try these tuning tips and references as have not focused on it yet but would be nice to get an extra 10 degrees.

Declan