Issues with raising boom? - SailNet Community
 
LinkBack Thread Tools
post #1 of 4 Old 07-15-2009 Thread Starter
Member
 
Join Date: Aug 2005
Location: Seattle, WA
Posts: 34
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
Issues with raising boom?

Good afternoon all,

Continuing my search for the right boat and trying to deal with my excessive height (6'3"), so now wondering what is involved in raising boom height. I understand it can be done, but should it be? In this instance, looking at a center cockpit Tayana 42 ... the boom catches me about the lower jaw. This seems a poor idea from a safety stand-point and from a bimini standpoint as I'll need shade and I like to stand upright from time to time. I was about to write off the boat design, but then raising the boom about 12" occurred to me.

Issues:

I have heard raising the boom can lead to excessive healing ... which frankly makes little sense to me since it is effectively a reef.

I have read it can lead to less weather helm and possibly lee-helm. This seems like a much more real consideration. How accurate is that and how could it be offset?

Could the weather helm issue be offset by going to a fuller, flatter or different sail shape? Gaff rig anyone?

Am I more worried than is necessary and in truth raising the sail 12 inches won't significantly impact anything?

How expensive/difficult would raising the boom be?

Any thoughts I haven't considered?

As always, thank to to everyone for any input!

"You've come to the wrong shop for anarchy ..." ~ Master and Commander

Last edited by Elzaar; 07-15-2009 at 06:47 PM. Reason: technical detail incorrect (typed mast, meant boom)
Elzaar is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 4 Old 07-15-2009
Old Fart
 
DwayneSpeer's Avatar
 
Join Date: Oct 2003
Location: Pasco, WA, USA
Posts: 514
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 12
 
Center of effort

I am certainly no expert but raising the boom has the obvious effect of raising the center of effort for the mainsail which should also increase the tendency to heel, however the smaller sail would reduce heeling so maybe the two factors would effectively cancel each other out.

This is an interesting question and I'm going to have to keep my eye on it. I hope you get some real expert help with it here.

Dwayne


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


Hey, can one of you guys pass me a crab?


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
DwayneSpeer is offline  
Quote Quick Reply Share with Facebook
post #3 of 4 Old 07-15-2009
An Aussie Sailor
 
Mipcar's Avatar
 
Join Date: Nov 2008
Location: Victoria,Australia
Posts: 122
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 7
 
I was thinking of raising my boom 6 inches. However I'll be lifting the mast out anyway for an overhaul so not such an issue for me. I expect it would take some significant modification to your mast.
Removing a foot of sail area I would think is fairly significant, if I do it to mine (6 inches) I'll be getting a new fully battened main to try to offset an power loses.

Mychael
Mipcar is offline  
Quote Quick Reply Share with Facebook
post #4 of 4 Old 07-15-2009
Telstar 28
 
sailingdog's Avatar
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 14 Times in 12 Posts
Rep Power: 14
         
Quote:
Originally Posted by Elzaar View Post
Good afternoon all,

Continuing my search for the right boat and trying to deal with my excessive height (6'3"), so now wondering what is involved in raising boom height. I understand it can be done, but should it be? In this instance, looking at a center cockpit Tayana 42 ... the boom catches me about the lower jaw. This seems a poor idea from a safety stand-point and from a bimini standpoint as I'll need shade and I like to stand upright from time to time. I was about to write off the boat design, but then raising the boom about 12" occurred to me.

Issues:

I have heard raising the boom can lead to excessive healing ... which frankly makes little sense to me since it is effectively a reef.
Actually, this isn't the case... Reefing a sail actually reduces the center of gravity, since the weight of the reefed portion of the sail is lower, and lowers the center of effort...

Raising the boom, raises the center of effort, while reducing sail area and raises the center of gravity—making it offset more of the keel's mass, reducing stability by raising the center of gravity slightly....

Quote:
I have read it can lead to less weather helm and possibly lee-helm. This seems like a much more real consideration. How accurate is that and how could it be offset?
Well, by reducing the area of the main sail, you're effectively shifting the center of effort forward, which will generally lead to some reduction in weather helm.

Quote:
Could the weather helm issue be offset by going to a fuller, flatter or different sail shape? Gaff rig anyone?
Going to a gaff rig doesn't make sense. It adds more weight aloft and generally requires a shorter mast than a marconi/bermudan rig. Adding roach to the main sail would shift the center of effort aft again, by adding area to the mainsail and might be a possible way to offset the shift caused by raising the boom and shortening the mainsail.

Quote:
Am I more worried than is necessary and in truth raising the sail 12 inches won't significantly impact anything?
You're shortening the widest part of the sail, so a 12" change is going to be a fairly large area of sail. Better to worry and find out that it wasn't necessary than to not worry and find out you were wrong.

Quote:
How expensive/difficult would raising the boom be?
This requires the gooseneck fitting and possibly the sail track to be altered on the mast. It also requires you to re-position fittings for the boom vang, if one is installed, and increases the length of some of the lines, as well as re-cutting the main sail. If the boom vang is a rigid model, you may need to replace it. If the boom is a furling boom, then it gets more complicated.... this would be best to consider on a boat that was only slab reefing.

Quote:
Any thoughts I haven't considered?

As always, thank to to everyone for any input!

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; 07-15-2009 at 09:18 PM.
sailingdog is offline  
Quote Quick Reply Share with Facebook
Reply

Quick Reply
Message:
Options

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
Deadly Serious about Booms John Rousmaniere Seamanship Articles 0 10-12-2004 08:00 PM
Control the Wicked Boom John Rousmaniere Gear and Maintenance Articles 0 05-06-1999 08:00 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