Proper mast rake - SailNet Community
Reply
 
LinkBack Thread Tools
post #1 of 19 Old 06-24-2006 Thread Starter
Member
 
Join Date: Aug 2005
Posts: 66
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 10
 
Proper mast rake

I race a Columbia Sabre. She's a 7/8 rig with straight spreaders and all shrouds parallel to the base of the mast (deck stepped). I am trying to find out how much rake to induce in the mast for our conditions 5-15 most of the time. I hired a local rigger to give me advice and he said 12" or more. This seems a bit extreme to me. Does anyone have a suggestion?
noscreenname is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 19 Old 06-24-2006
Member
 
Join Date: Jun 2006
Posts: 72
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 10
 
On my J/24, the mast clearly has more rake than the cruisers at the dock... they're all lined up in a row, and my boat may have as much as 8-12" more rake. Not sure how much rake in a cruiser, but I'm assuming there is some, so 12" total may not be as much as you think.

Mike
pluscard is offline  
Quote Quick Reply Share with Facebook
post #3 of 19 Old 06-25-2006
Senior Member
 
paulk's Avatar
 
Join Date: Jun 2000
Location: CT/ Long Island Sound
Posts: 2,605
Thanks: 4
Thanked 26 Times in 25 Posts
Rep Power: 16
 
The amount of rake you want depends upon the boat. The idea is to use mast rake to balance the helm. Doing this helps keep the boat sailing faster, since (with the forces at work on the hull and keel and sails) you're not always keeping the tiller at an angle in order to get the boat to go straight. Rake also helps use the weight of the mast and the force of the backstay to keep the forestay tight, so you can head closer to the wind. This is especially important for racers -- hence the hefty rake mentioned for a J/24.
Rake is not the same thing as mast bend: curving the mast so as to flatten the sail. You shouldn't have to worry about mast bend much with a Columbia Sabre. Getting the mast to bend even just 4" would likely be an effort, and in less than 15 knots, probably not any use. Your sailmaker can tell you more about that.

In the meantime, attach your main halyard to a wrench by the hole in the end of the wrench handle and put a yardstick down on your cabintop, aft of the mast. Adjust the forestay (don't forget to loosen the backstay) until the wrench kisses the 12 when the boat stops bobbing from you moving around. Snug up the backstay and go out sailing. Feel any difference on the helm? If there's too much weather helm going upwind, take some rake out. Too little helm, add more rake. It's not Rocket Science, but it should make sailing the boat easier (less fighting the helm) and improve performance.
paulk is offline  
Quote Quick Reply Share with Facebook
post #4 of 19 Old 06-25-2006
Partially hydrated Member
 
Join Date: Mar 2006
Location: Salem, OR
Posts: 98
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 10
 
Question mast rake

paulk -
Do you mean you want more slope of the mast towards the bow of his boat? I was under the impression that rake meant toward the stern. I am re-rigging a 37 ft. cruiser and need to find the best mast angle. It has much too much weather helm to the tiller, which wears out the helmsman on an afternoon cruise. Any suggestions?

Randy
sanjuan2R is offline  
Quote Quick Reply Share with Facebook
post #5 of 19 Old 06-25-2006 Thread Starter
Member
 
Join Date: Aug 2005
Posts: 66
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 10
 
No such thing as forward rake, Meaning beyond vertical. No boat will point well with the mast forward. The question is Deg of rake relative to it's design,For instance I believe j boats use a lot of rake,105's use 20+ inches because the mast is ahead of the keel thus if the mast were left straight there would be too much lee helm.
As I understand it more rake = more helm and I'm struggling to find that balance. In our case we now have 12" of rake but the rigger accomplished this by adding 3 toggles in front and shortening the back stay.(Not good) I now have what I believe to be a little more rake than needed and the foot of the sail is 10" or more off the deck at the tack and several feet at the clew, so much for the "end plate effect". We raced the other night with this set up for the first time and finished 7th when we've never finished below top 4.
In my case the heavy rake induced some helm,enough to point better, but the lifted Jib was under powerd so we pointed without speed.
In any case it's never desirable to have the mast leaning forward.
noscreenname is offline  
Quote Quick Reply Share with Facebook
post #6 of 19 Old 06-25-2006
Telstar 28
 
sailingdog's Avatar
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 15 Times in 12 Posts
Rep Power: 14
         
Most boats should have just a touch of weather helm, which is good, and helps the steering be more responsive, helps the boat point a bit better, and helps generate a bit of underwater lift to windward. The worst thing to have is lee helm, where the rudder helps stall the boat.

Also, might want to look at this thread: Mast Rake

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.

Last edited by sailingdog; 06-25-2006 at 06:41 PM.
sailingdog is offline  
Quote Quick Reply Share with Facebook
post #7 of 19 Old 06-27-2006
Just another Moderator
 
Faster's Avatar
 
Join Date: Sep 2005
Location: New Westminster, BC
Posts: 16,534
Thanks: 104
Thanked 312 Times in 300 Posts
Rep Power: 10
     
"In any case it's never desirable to have the mast leaning forward." by noscreenname...

Suggest you look more closely during the America's Cup next time around when the boats are running. Many race boats do, in fact, if they have the capability, lean their rigs dramatically forward on downwind legs.

Admittedly it's not something you see much of during the local club events.
Faster is offline  
Quote Quick Reply Share with Facebook
post #8 of 19 Old 06-27-2006 Thread Starter
Member
 
Join Date: Aug 2005
Posts: 66
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 10
 
Quote:
Originally Posted by Faster
"In any case it's never desirable to have the mast leaning forward." by noscreenname...

Suggest you look more closely during the America's Cup next time around when the boats are running. Many race boats do, in fact, if they have the capability, lean their rigs dramatically forward on downwind legs.

Admittedly it's not something you see much of during the local club events.
Agreed but I was discussing pointing ability.
noscreenname is offline  
Quote Quick Reply Share with Facebook
post #9 of 19 Old 06-27-2006
Moderator
 
Jeff_H's Avatar
 
Join Date: Feb 2000
Location: Annapolis, Md
Posts: 6,908
Thanks: 5
Thanked 152 Times in 124 Posts
Rep Power: 10
     
Historically, boats of that era were typically designed with a 1/4" of rake per foot, and then tuned to provide a balanced helm. 5.5 meter class boats of that era (which is what the Sabre was) typically began life without a huge amount of rake or bend in lighter going and a bit more in heavier winds which seems counter intuitive but more backstay pressure meant more headstay pressure.

For the record, a boat designed for forward mast rake will point perfectly well with foreward mast rake. Some IOR era boats were designed that way. Went up wind just fine. Its all about the design of the boat.

Jeff
Jeff_H is offline  
Quote Quick Reply Share with Facebook
post #10 of 19 Old 06-28-2006
Member
 
Join Date: Jun 2006
Posts: 80
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 10
 
On boats like H-Boats, having the mast lean forward is done. I agree that it improves performance.
infonote is offline  
Quote Quick Reply 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:
OR

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
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Electrolysis / Keel stepped mast WillS Gear & Maintenance 14 06-27-2006 01:45 PM
Mast Rake for Cape Dory 30 Bob Ohler General Discussion (sailing related) 3 08-08-2001 09:03 AM
Spartite 2000 mast wedge replacement system - need info Capt.CarroleWard Gear & Maintenance 2 05-30-2001 06:01 PM
Changing mast from keel to deck step vickers41 General Discussion (sailing related) 1 04-10-2001 02:08 PM
Ericson- Mast Compression Problem Jeff_H Gear & Maintenance 2 12-31-2000 09:30 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