Port vs. Starboard tacks - Page 2 - SailNet Community
Seamanship & Navigation Forum devoted to seamanship and navigation topics, including paper and electronic charting tools.

LinkBack Thread Tools
post #11 of 14 Old 11-26-2007 Thread Starter
Senior Member
Zanshin's Avatar
Join Date: Aug 2006
Location: Germany
Posts: 2,333
Thanks: 0
Thanked 32 Times in 30 Posts
Rep Power: 11
Mainsail is in-mast, so no drag difference whether furled or not. The headsail was reefed, so a 3-4cm rolled section would disturb the airflow more on starboard tack, but just the leading edge wasn't laminar - I would be amazed if this causes a difference of over 20% though.
I've just spent the past couple of hours trying to repair the work that the yard did on my ship At least I'm attached to power for the first time in a week and have the air cranking while I'm head down in the bilges.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Zanshin is online now  
Quote Quick Reply Share with Facebook
Sponsored Links
post #12 of 14 Old 11-26-2007
Telstar 28
sailingdog's Avatar
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 18 Times in 14 Posts
Rep Power: 16
Umm... if it is like other mainsail in-mast furling systems, it will be biased a bit to one side when reefed... and essentially centered when not reefed.. so it too may have had some effect on the performance, since the sail shape will be slightly different.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

sailingdog is offline  
Quote Quick Reply Share with Facebook
post #13 of 14 Old 11-26-2007
Senior Moment
SailorMitch's Avatar
Join Date: Nov 2005
Location: MD
Posts: 1,931
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 12
As others have suggested, use the GPS the next time conditions are good for a cross check. It the speed difference still exists, check the rig to make sure the mast is centered, is in column, etc. Yes, get a Loos gauge for the rig to check the stay tension side to side.

Sailing winged keels since 1989.
1.20.09 Bush's last day the end of an error !! Hopefully we still have a constitution and economy left by then.

"Compassion and tolerance are not a sign of weakness, but a sign of strength." The Dalai Lama

good planets are hard to find-- a song by steve forbert

I have but one lamp by which my feet are guided, and that is the lamp of experience. I know no way of judging the future but by the past.-- Patrick Henry.
SailorMitch is offline  
Quote Quick Reply Share with Facebook
post #14 of 14 Old 11-27-2007
Larus Marinus
Idiens's Avatar
Join Date: Jan 2007
Location: Brussels
Posts: 1,756
Thanks: 0
Thanked 2 Times in 2 Posts
Rep Power: 11
Originally Posted by Zanshin View Post
Y... I was using a log wheel, which is forward of the keel and only about 4 inches off the centreline (it is to port).
My log wheel is also offset and I get different readings on opposite tacks, though not as much as you are seeing. I theorise that, as the boat is (what's the word?) crabbing sideways while close hauled, especially in a seaway, the flow over the log wheel will be affected by the hull shape differently on either tack. GPS will give a good comparison but for any accuracy you really need recordings. Both the GSP and the log wheel electronics are averaging a series of measurements and pitching particularly introduces a different variation to both.

I think SD had a good point about the accuracy of the wind instrument, the head to wind setting has to match both the aerodynamic and hydrodynamic centre lines and the boat's centreline.
Idiens is offline  
Quote Quick Reply Share with Facebook

Quick Reply

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Similar Threads
Thread Thread Starter Forum Replies Last Post
Starboard and Port tacks? ImASonOfaSailor General Discussion (sailing related) 74 07-30-2012 08:58 PM
Faster on Starboard than Port. Why? IrishMistRacing Racing 20 08-21-2006 08:35 PM
Sailing Basics Steve Colgate Learning to Sail Articles 0 03-09-2003 07:00 PM
Sailing Basics Steve Colgate Seamanship Articles 0 03-09-2003 07:00 PM
Sailing Basics Steve Colgate Her Sailnet Articles 0 03-09-2003 07:00 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome