Why does my boat sail closer to the wind on a Port Tack?

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Boeingdr

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This is probably a dumb question, but I'm learning as I go here.....
I noticed last season that my boat (Seamaster815) seemed to sail closer to the wind on a port tack. I re launched 3 weeks ago and was out experimenting today (beautiful morning here!).
Today I was using headsail alone (large 140% genoa) and managed(about 40deg rel) and about 4.5kts on a port tack as opposed to 60 deg rel and 3.2kts on a starboard tack.
Is it likely to be something to do with the rigging or would factors like tide have an influence?
Any advice appreciated.
 
Canyou confirm what you are using to tell how close to the wind you are sailing?

If it is an electronic wind indicator (e.g. ST60 or similar) you will have to check that it is calibrated (check manual for set up). Also if it is just a wind indicator (direct e.g. a Hawk or similar) it may not be pointing true to the bow of the boat.

As for the speed. Although I have played about with my ST60 speed transducer, it still under-reads on one tack compared to the other. This is because it is situated on the starboard side just forward of the keel. I will just have to learn to live with the difference.

Hope this helps.

Donald
 
Firstly, how are you measuring it? Is it an electronic wind indicator and is it set up true fore and aft? Ie are you absolutely sure that it does perform better under one tack than the other. Logs will tend to read differently on the different tacks, so take care with this as well.

Second, look at the mast set up. Use a halyard to measure wether the mast is pointing upright. If so run your eye up the track to make sure it is true.

Presume the sheets are going back to the same place so the genoa shape is consistent?

Simple things like weight distribution can also be a factor - eg full water tank under a port hand berth.

Tide will have effect on true bearing to wind, but if you are using your boat's instruments then chances are you will be measuring relative directions and speeds (apart from GPS).

If there are any waves they may be more pronounced on one tack and slow the boat down more.
 
Tidal factors havea consideable influence on COG (course over ground), but if you are simply not able to head as close to the wind on one tack as the other then it is likely the mast is not stepped vertically to the hull. Other factors come into play as well when using the main, such as a bend induced by the rigging being incorrectly tightened. Try sighting up the mast track, any bend will be obvious. Bends will not affect the jib by itself so much though unless it is allowing the leading edge to sag more on one tack than the other. Best get a rigger to spend time with you to check it all out.
 
Variables (in no particular order) are:
Foils
Sails / rig
Hull
Instruments

If any of the first three are out of whack (assymetrical) that could explain the difference. Or the instruments might not be set up properly.

It really could be any of the factors, or a combination. The easiest ones to look for and adjust are probably rigging (making sure the rig is square in the boat and properly tensioned) and proper instrument calibration. If the problem is the location of the paddlewheel (not on the centerline) you can probably move it, but probably no easily (or it would have been put on the centerline in the first place!)

Underwater foils can also be checked for symmetry and modified, but obviously that is a bigger job. If the hull is the problem ... well that one just doesn't bear thinking about - in that case you might just want to live with it!
 
For that amount of difference I would strongly suspect your instrumentation rather than any genuine difference. You should also perhaps record the apparent wind speed on each tack as if the tide is strong and the wind is weak there may be a significant difference between the tacks
 
Agree with all the above - also right-handed people tend to THINK that their boat sails better on port whether it actually does or not! It's something to do with hand-eye coordination - then you start trying to justify it, anyway a boat will always go better on one tack than the other!
 
Best way to check whats really happening is to get out there alongside another comparable boat and both sail the same angles and simply forget the instruments.
If he can sail higher than you then you can tune your own boat until you match him. If you can't match him - it could be rig tension, keel shape - a host of things.
And if you both sail the same - then maybe check the instrumentation!
Good luck
JOHN
 
I would add to that list, weight distribution affecting the trim of the boat.

The cockpit locker full of weighty items on the same side as the fuel/water tanks will result in a permanent list.

The list will affect your pointing ability.
 
Thanks for all the replies,
I was using a wind vane and electronic wind instrument which was showing relative wind. Speed was using gps SOG so i guess I should of been looking at the log although that isnt very reliable.
Some really good replies here for me to consider.
I suspect I need to check that my mast is stepped vertical plus my boat does tend to list a little to port due to the cockpit locker on this side along with liferaft inside.
 
Ive just checked the tidal stream using my pc navigator programme - the tide was almost exactly in the same direction as the wind at 0.5kts (ie wind was from NW as I remember and the tide was running SE).
 
I would check to see the mast is not bent or out of vertical both athwartships and fore and aft. A liitle rake aft and a tad mast bend may help weather helm but no bends to leeward on either tack. leeward shrouds not be slack when beating.
If you can dry out alongside a pier, check the keel is not out of true, happens more often than you might think.
grahmc
 
Thanks, I think the keel being out of true can be discounted becauseIv only just launched and she was on a cradle when out of water - everything looked aligned.
 
Just as a matter of interest my little boat has always sailed better on port tack. it is not a measurable thing just better speed or pointing when compared to other boats. We are talking tinny margins.
It has always been like that over 25 years several masts stays etc. I have looked at the keel from all angles and it seems OK. So we just live with it. olewill
 
My Foxcub seems to sail slightly better on a port tack. No log or compass, just a feeling and the chuckle from the wake.
I put it down to the backstay being slightly off-centre to avoid the rudder headstock.
 
Hi Phil most boats have a backstay that is spilit with a wire each side of the rudder. They join about 1.6 metres above the transom.
You can hae it join at a pulley so a tackle on one side gives you an adjustable backstay with 2:1 purchase before you put the tackle on onne side. Or alternatively many mast head rig boats have a plate with 2 pulleys which can be pulled down by another tackle to pull the legs together so tighteni9ng the backstay.
But then I am sure you know all this. It makes a bigger difference in performance in strong winds on a bendy fractional rig but can help to flatten the mainon a mast head rig if the inner forestay is tight.
I don't think it would make any difference to the performance on different tacks with only one off centre backstay leg. olewill
 
i noticed this year before last, then spotted the car for the gennie sheet was in a different position from one side to the other !!! dohh!!
 
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