Windward performance - Page 3 - SailNet Community
 2Likes
Reply
 
LinkBack Thread Tools
post #21 of 22 Old 04-01-2012
Low Salt Diet Sufferer
 
Join Date: Feb 2010
Location: San Francisco Bay Area
Posts: 64
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 6
 
Re: Windward performance

Quote:
Originally Posted by AdamLein View Post
Are you wondering about hydrodynamic effects on the leeward side, or aerodynamic effects on the weather side?

In the first case, if you're heeled over that far you have other problems. In the latter, I can't imagine it would have much affect on windage.
I am wondering about the hydrodynamic effects. For instance, does pronounced tumblehome produce a lift to leeward? Or maybe it helps the leeward hull side "stick" in the water and reduces leeway?

The boat with pronounced tumblehome I have sailed on is a Catalina 38 which points and goes to windward very well, and buries the rail (and of course the tumblehome) when there is sufficient wind. It seems to like that.

The tumblehome was part of an S&S race design as I understand it, so I am assuming it was done very purposefully. But why?
kulokoo is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #22 of 22 Old 04-01-2012
Closet Powerboater
 
MedSailor's Avatar
 
Join Date: Mar 2008
Location: Anacortes PNW
Posts: 3,541
Thanks: 253
Thanked 110 Times in 100 Posts
Rep Power: 8
 
Re: Windward performance

Quote:
Originally Posted by kulokoo View Post
I am wondering about the hydrodynamic effects. For instance, does pronounced tumblehome produce a lift to leeward? Or maybe it helps the leeward hull side "stick" in the water and reduces leeway?

The boat with pronounced tumblehome I have sailed on is a Catalina 38 which points and goes to windward very well, and buries the rail (and of course the tumblehome) when there is sufficient wind. It seems to like that.

The tumblehome was part of an S&S race design as I understand it, so I am assuming it was done very purposefully. But why?
It may have been for looks, reminiscent of when tumblehome kept the weight of the cannons closer to the center-line and helped deflect cannon-balls. Not all design features are for performance. These links might help:
Tumblehome, stability, and performance

Boat Design Forums

From the link above:
"There are several advantages to tumblehome: as already mentioned, it reduces inverse stability; it allows outboard shrouds to be moved in relative to overall beam and thereby reduces sheeting angles; since a curved panel is stronger than a flat one for a given scantling, one can achieve greater strength with less displacement. The disadvantages are reduction in side deck area and a slight increase in tooling costs. Since offshore racing boats do not utilize outboard shrouds, one can only assume that the reduction in side deck area was a safety factor considered more important by the developers of a rule intended for crewed vessels. Brad"

I have a sauna on my boat, therefore I win.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
MedSailor 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
What would you buy for $100,000? swo104 Boat Review and Purchase Forum 130 08-30-2013 11:51 AM
low-budget performance passage-maker catamount Boat Review and Purchase Forum 16 07-12-2005 06:12 PM
Performance 420 Stepford Boat Review and Purchase Forum 2 09-27-2004 04:56 PM
Gibsea Quality / Sail Performance corvette4_5_4 Boat Review and Purchase Forum 8 03-21-2002 10:58 PM
best "performance" cruiser ~100K wardtj Boat Review and Purchase Forum 4 01-13-2002 07:08 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