Port vs. Starboard Tack

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Apr 12, 2007
206
Hunter 420 Herrington Harbor South
I think I saw something here before but am unable to fine it.
I seem to get ½ to ¾ Kt, additional speed on a port tack than on starboard. Same wind speed, same AOA (as best I can tell), same trim (as close as I can), and same relative rudder position. There are no asymmetric loads she sits level. Everything is as close to a mirror image as I can get.
Thoughts or answers?
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
don't know of a single boat that does not have this issue. Just try building a bimini and you will quickly find that port and starboard are not "exactly" the same. All the little differences add up to one tack being preferred
 
Nov 8, 2010
11,386
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
GPS or knotlog (impeller) speed?

If knotlog, that's actually rather typical. Wear, off-axis mounting, or a mount off the centerline of the boat will all cause it.
 
Apr 12, 2007
206
Hunter 420 Herrington Harbor South
GPS -- cross checked on 3 seperate units. Oh well Its port for me

Thanks
 
Nov 8, 2010
11,386
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
Is your mast plumb?

It COULD be your keel. They get bolted on crooked all the time.
 
Apr 12, 2007
206
Hunter 420 Herrington Harbor South
Stright, had rigging checked and tuned last season. If its the keel (winged) guess I live with it. Seems that would be a major redo.:neutral:
 

Ray T

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Jan 24, 2008
224
Hunter 216 West End - Seven Lakes
I read in one of the magazines that this was a problem with a lot of boats. The article stated that since boat hulls aren't all that precision that you can't get a good mast alignment by measuring with the main halyard to the deck. His solution was to align the mast to the trailing edge of the keel. Doing this would eliminate the lack of precision in the hull. Obveously you would have to do this when the boat was hauled. I don't remember how he did the sighting for the alignment but if you wan't to do this I'm shure you'll find a way .
 
Sep 25, 2008
1,096
CS 30 Toronto
I read in one of the magazines that this was a problem with a lot of boats. The article stated that since boat hulls aren't all that precision that you can't get a good mast alignment by measuring with the main halyard to the deck. His solution was to align the mast to the trailing edge of the keel. Doing this would eliminate the lack of precision in the hull. Obveously you would have to do this when the boat was hauled. I don't remember how he did the sighting for the alignment but if you wan't to do this I'm shure you'll find a way .
Wave and current
 
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