Port Tack faster than Starboard

Boat handling, ideas, questions...
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Ereiss
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Joined: Sat Dec 06, 2008 12:32 pm

Port Tack faster than Starboard

Post by Ereiss »

I've noticed the last couple of times out (may have always been the case) that I am noticeably faster (speed over ground) on a port tack than on starboard. It is not current related as I was tacking across the current.

The traveler is centered and I can think of no other adjustable that would account for this.

Has anyone else noted this behavior? Not a big deal but a curiousity.

Almost time to pull the boat, it feels like fall has arrived here in Massachusetts.
Ed Reiss
Being There
F38 - #154
out of Marion, MA

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Alain
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Location: F39PH
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Re: Port Tack faster than Starboard

Post by Alain »

Ereiss wrote:I've noticed the last couple of times out (may have always been the case) that I am noticeably faster (speed over ground) on a port tack than on starboard.
Readings from GPS or speed transducer (paddlewheel)?
Alain
Naïade, F39PH '83, Montréal

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Ereiss
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Re: Port Tack faster than Starboard

Post by Ereiss »

Sorry, it was on the gps. I always assumed the paddlewheel would give different speeds as it is not on the center line.
Ed Reiss
Being There
F38 - #154
out of Marion, MA

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Michel
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Location: Zaanstad, the Netherlands, EU

Re: Port Tack faster than Starboard

Post by Michel »

Ed,

Do you have leveled clinometer to check heel? Your boat might have a slight list and therefore heel more on one tack. I had this (and many others too) on my F33/35 cat ketch due to tank-, furniture and storage placement.
Michel Capel, Freedom 44 #4 1981 'Alabama Queen', NED8188, cat ketch with wishbones, home port Enkhuizen, the Netherlands, 52*42.238'N 005*18.154'E.

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numbknots
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Location: Sunny Florida

Re: Port Tack faster than Starboard

Post by numbknots »

Here's a thought. What if it one side of your hull gets fouled more thatn the other, I know when cleaning my bottom the
sunny side grows more slime and barnnacles than the other. Mast bend might also be different on each tack. The good news is your not able to go upwind on either tack anyway. Numbknots
... currently experiencing performance anxiety..,

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Castaway
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Location: Lerwick, Shetland Isles

Re: Port Tack faster than Starboard

Post by Castaway »

Castaway is faster on Starboard tack, we always find. We carry more weight to port, but not enough to cause more than a degree of heel, and fouling is even both sides (and minimal- there are advantages to cold water). In days gone by, a hull would be built by a master shipwright on one side, and his apprentice on the other, causing some asymmetry of line, which would account for this. Even on a modern glass fibre boat, you will find this difference. Our F21 is quite different port to starboard, as we found when cutting out lining material; mirrored cuts did not fit!

There may well be other reasons, such as how the sails sit, which side their stitching is, torque from the propeller, etc. Is there an expert opinion out there?
Gerald Freshwater,
s/y 'Castaway', (UK F35 cat ketch, centreboard, 1987)
Lerwick Boating Club
Shetland Isles, Scotland

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Hans
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Re: Port Tack faster than Starboard

Post by Hans »

That a ( main-) sail needs twist is common knowledge. Less well known is that the amount of twist differs on port- and starboardtack.
This is caused by the effect of Coriolis on the wind. Creating a 'true wind shift'. The effect is more outspoken on higher altitudes, and
contrary on Northern and Southern hemispheres.

In theory every sailboat favors on the Northern hemisphere the starboard tack ( or 'sailing over bakboord' as we say in Dutch) when mainsail twist is
similar on both tacks and when other factors as hull symmetry and weightdistribution etc. are ruled out.

An article which explains this in detail is found at: http://www.oceansail.co.uk/Articles/Win ... ticle.html


Good sailing,

Hans
Hans Hansen, Makkum,The Netherlands.
Freedom 45AC #47 "Scherezade".

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