Port vs. Starboard tacks - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Chat  
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > Skills and Seamanship > Seamanship & Navigation
 Not a Member? 

Seamanship & Navigation Forum devoted to seamanship and navigation topics, including paper and electronic charting tools.


Reply
 
LinkBack Thread Tools
  #1  
Old 11-26-2007
Zanshin's Avatar
Senior Member
 
Join Date: Aug 2006
Location: Germany
Posts: 2,215
Thanks: 0
Thanked 17 Times in 17 Posts
Rep Power: 9
Zanshin is on a distinguished road
Port vs. Starboard tacks

I've noticed a significant difference in my boat's performance, my starboard tack is about 1.5 knots slower than my port tack. I have a large water tank on my starboard side and thought that this might be a factor. Yesterday we had some very stong conditions and my destination was about 20 miles directly upwind, with the waves and current head-on as well. I had 2 reefs on both sails (25+ knots) and actually measured performance for the first time.

I would sheet in the genoa identically on both tacks, pulling the sheets back to the aft spreaders. I had adjusted the main until I had only about 2-6 degrees of weather helm on both tacks. This gave me 8.2 knots on starboard tack but only 6.5 or so on port tack. I don't have an inclinometer, but I was well heeled over and it seemed to be about the same angle, and I kept the angle to the wind identical on port and starboard tack as well.
I couldn't more than 7kn on port tack without letting out a reef. I'd emptied the starboard watertank completely, so I think that my boat is evenly statically balanced. The rigging looks straight and tensions are similar on both sides as well as fore-and-aft.

Is this rather large difference normal or acceptable? Is a rigger likely to find some way to balance this out? Could there have been some prior damage (i.e. grounding) which might have caused a slight deformation of the keel that can be causing this?
__________________

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.
Reply With Quote Quick reply to this message Share with Facebook
  #2  
Old 11-26-2007
Idiens's Avatar
Larus Marinus
 
Join Date: Jan 2007
Location: Brussels
Posts: 1,756
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 9
Idiens is on a distinguished road
How were you measuring your speed? If with a log wheel, is the wheel symmetrically placed on th hull? If with GPS, what currents were predicted? Does your compass have the ability to measure/display heel angle? You mention the weather helm, was it the same on both tacks? Were the waves coming down wind or were they slightly offset?

I think there was another thread on this question and it seemed to end up with asymmetric rigging tension.
Reply With Quote Quick reply to this message Share with Facebook
  #3  
Old 11-26-2007
sailingdog's Avatar
Telstar 28
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 13 Times in 11 Posts
Rep Power: 13
sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice
Zanshin—

First, Idiens points about how you're measuring things is very key... it is hard to accurately measure the difference between port and starboard tacks, since it is very difficult to have the exact same conditions on both tacks.. with respect to currents, and such.

Also, if your wind instruments are off a bit... say 5˚, you could actually be sailing ten degrees higher on one tack than the other, and that could easily cause such a difference in boat speed.
__________________
Sailingdog

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.
.

Still—DON'T READ THAT POST AGAIN.
Reply With Quote Quick reply to this message Share with Facebook
  #4  
Old 11-26-2007
Senior Member
 
Join Date: Jun 2005
Location: New Orleans
Posts: 1,943
Thanks: 8
Thanked 32 Times in 29 Posts
Rep Power: 10
nolatom will become famous soon enough
If everything's roughly symmetrical in your hull, straightness and plumbness of spar, sails, and weight distribution, then the conditions you're sailing in may be the factor. Double-reefed in heavy wind, seas, and current may not the best time to compare performance this way. The angle of the current (if not truly head-on), shape and angle of the seas, and difference in wind gusts can make a difference you're not aware of (assuming you're using GPS to get speed readings).

I've often found in sloppy conditions that sometimes one tack is just "better" than the other, in a boat which otherwise sails the same close-hauled on either tack. Try your boat in lighter air, no-reef, no current conditions if you can find them, and see what happens then.
Reply With Quote Quick reply to this message Share with Facebook
  #5  
Old 11-26-2007
sailingdog's Avatar
Telstar 28
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 13 Times in 11 Posts
Rep Power: 13
sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice
One other thing, the main sail shape may be somewhat different on the two tacks with the sail reefed, since on most boats, the reefing tack cringle will be brought down to a cringle hook on one side of the gooseneck, leading to an asymetrical sail setup. The sail's reefing clew cringle is often also biased a bit to one side or another, depending on how the reefing lines are lead.

These differences in the reefed mainsail's shape could also account for the differences.

Nolatom's point about trying the test in lighter wind, with less swell/chop, an unreefed mainsail, and preferably with no current... and see what happens.
__________________
Sailingdog

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.
.

Still—DON'T READ THAT POST AGAIN.
Reply With Quote Quick reply to this message Share with Facebook
  #6  
Old 11-26-2007
TrueBlue's Avatar
Seńor Member
 
Join Date: Oct 2004
Location: Narragansett Bay
Posts: 4,853
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 13
TrueBlue is a jewel in the rough TrueBlue is a jewel in the rough TrueBlue is a jewel in the rough
No one has mentioned rudder angle; the drag from which would affect boat speed, if not consistent for each tack.
__________________
True Blue . . .
sold the Nauticat

Last edited by TrueBlue; 11-26-2007 at 12:33 PM. Reason: dyslexic moment
Reply With Quote Quick reply to this message Share with Facebook
  #7  
Old 11-26-2007
Zanshin's Avatar
Senior Member
 
Join Date: Aug 2006
Location: Germany
Posts: 2,215
Thanks: 0
Thanked 17 Times in 17 Posts
Rep Power: 9
Zanshin is on a distinguished road
Yesterday was the first time that I took the effort to measure things, particularly as I'd emptied the asymmetrical weight of the water tank. I was sailing directly against a .25 knot current and the waves were head on to the wind which made measurement simpler. I was using a log wheel, which is forward of the keel and only about 4 inches off the centreline (it is to port). I didn't use a GPS, I'll do that next time out. In my case both Genoa and Main are furling (genoa closing to clockwise, main closing counterclockwise) and with 2 reefs there is a definate obstruction in the luff when on a starboard tack. Both directions had the same heel (a couple of inches shy of the toerial) and weather helm. I'll check today to see if the wind instrument reads true - as I was basing my heading on the wind angle and didn't cross-check with compass headings. The forecast is for choppy 4-6 seas and 20+ wind spees until later this week so I won't be testing further for a while. But for those interested, I'm using the free wifi at Saba Rock but can't take any more pictures. In the process of assisting a stranded kite surfer with a disabled kite about a half mile offshore yesterday (I saw the glint of something and decided to investigate on the dinghy) I managed to get my camera inundated...
__________________

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.
Reply With Quote Quick reply to this message Share with Facebook
  #8  
Old 11-26-2007
Senior Member
 
Join Date: May 2002
Posts: 2,573
Thanks: 3
Thanked 20 Times in 18 Posts
Rep Power: 13
Sailormon6 will become famous soon enough
Depending on how your boat's keel and rudder are configured, prop drag could be creating a slight sideways component when the prop is either freewheeling, or atilt slightly one way or the other.
Reply With Quote Quick reply to this message Share with Facebook
  #9  
Old 11-26-2007
bestfriend's Avatar
Hitchin' a ride
 
Join Date: Sep 2006
Location: In my mind, I live in Oslo
Posts: 3,191
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 11
bestfriend is a jewel in the rough bestfriend is a jewel in the rough bestfriend is a jewel in the rough
Get yourself a Loos tension gauge.
__________________
Great men always have too much sail up. - Christopher Buckley


Vaya con Dios
Reply With Quote Quick reply to this message Share with Facebook
  #10  
Old 11-26-2007
sailingdog's Avatar
Telstar 28
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 13 Times in 11 Posts
Rep Power: 13
sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice
If the headsail and main were furled, the airflow over them wouldn't be symmetrical, since they're both roller furling... so that alone might explain the differences..
__________________
Sailingdog

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.
.

Still—DON'T READ THAT POST AGAIN.
Reply With Quote Quick reply to this message Share with Facebook
Reply

Quick Reply
Message:
Options

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:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

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

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


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


All times are GMT -4. The time now is 08:37 AM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2015, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.