Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 19-08-2013, 14:59   #1
Registered User

Join Date: May 2012
Location: Baltimore, MD
Boat: Cal 2-27
Posts: 843
Discussion. Help me understand more in depth...clr! looks can be deceiving

Ok. Here goes. Looking at the 2 boats in the attached photos. You will notice a fin keel on the Cal 40 and full keel on the Norsea.

That being said. Look at where the center of lateral resistance is located o the hull. More centered on the Cal and more toward the rear on the Norsea.


Wouldn't this make a full keel boat's bow "blow off" much more than a fin keel? I have heard plenty of stories of great pointing full keel boats, but I'm only really exp. on fin keel as a point of actual personal reference.

I would LOVE to sail both boats in similar conditions around a course to get a better understanding from personal exp, but will have to come here to ask instead.

Can the Norsea or another full keel boat point as high as the fin keel?
Attached Thumbnails
Click image for larger version

Name:	cal.jpg
Views:	93
Size:	6.7 KB
ID:	65741  
Attached Images
 
__________________

__________________
76% of statistics are made up.
boatsail is offline   Reply With Quote
Old 19-08-2013, 15:02   #2
Senior Cruiser

Cruisers Forum Supporter

Join Date: Jul 2005
Boat: Outbound 44
Posts: 4,584
Re: Discussion. Help me understand more in depth...clr! looks can be deceiving

The simple answer is no. A full keel may track better, i.e. stay in a straight line, better, but it won't point as high as foiled fin keel.
__________________

__________________
Paul L
http://svjeorgia.blogspot.com
Paul L is online now   Reply With Quote
Old 19-08-2013, 15:04   #3
Registered User
 
Wrong's Avatar

Join Date: Jul 2013
Posts: 1,702
Re: Discussion. Help me understand more in depth...clr! looks can be deceiving

"Look at where the center of lateral resistance is located o the hull. More centered on the Cal and more toward the rear on the Norsea."

Your objective criteria for making this statement please?
__________________
Wrong is offline   Reply With Quote
Old 19-08-2013, 15:07   #4
Registered User
 
Wrong's Avatar

Join Date: Jul 2013
Posts: 1,702
Re: Discussion. Help me understand more in depth...clr! looks can be deceiving

Quote:
Originally Posted by Paul L View Post
The simple answer is no. A full keel may track better, i.e. stay in a straight line, better, but it won't point as high as foiled fin keel.
Pretty presumptive statement considering only two boats are under consideration. Don't you think it depends upon the boat design, weight distribution and sail plan? Some boats with 'foil fin keels' will sail like a pig...
__________________
Wrong is offline   Reply With Quote
Old 19-08-2013, 15:11   #5
Registered User

Join Date: May 2012
Location: Baltimore, MD
Boat: Cal 2-27
Posts: 843
Re: Discussion. Help me understand more in depth...clr! looks can be deceiving

Quote:
Originally Posted by Wrong View Post
"Look at where the center of lateral resistance is located o the hull. More centered on the Cal and more toward the rear on the Norsea."

Your objective criteria for making this statement please?
That is the reason I was asking the question. I don't have a degree in engineering or physics. When I observe the two pictures I applied rationale.

If I were to draw a vertical line centered between the bow and stern of each boat, and pushed each "half" with equal force, what half would have less "friction" and therefore "give way" more. To me the answer is that the Norsea has less friction under the front half of the boat, so therefore would not be able to point as well due to the bow "blowing off" more than say the Cal I used in the example.

I don't know if I'm right or wrong, but figured that the knowledge base on here could probably give a more technical answer than mine and I could learn something from this thread and maybe others could too.

Plus, it was either this or start a gun thread.
__________________
76% of statistics are made up.
boatsail is offline   Reply With Quote
Old 19-08-2013, 15:12   #6
Registered User
 
Teknav's Avatar

Join Date: Jul 2012
Location: Texas - USA
Boat: Twin Otter de Havilland Floatplane
Posts: 1,838
Re: Discussion. Help me understand more in depth...clr! looks can be deceiving

Sailing like a pig, may not necessarily be bad! Flying like a pig, is a whole new thread!

Mauritz
Going to behave someday!
__________________
Retired - Don't Ask Me To Do A Damn Thing!
Teknav is offline   Reply With Quote
Old 19-08-2013, 15:14   #7
Registered User
 
Wrong's Avatar

Join Date: Jul 2013
Posts: 1,702
Re: Discussion. Help me understand more in depth...clr! looks can be deceiving

Quote:
Originally Posted by Teknav View Post
Sailing like a pig, may not necessarily be bad! Flying like a pig, is a whole new thread!

Mauritz
Going to behave someday!
See: 'Flying Hawian is Gone' for that discussion...
__________________
Wrong is offline   Reply With Quote
Old 19-08-2013, 15:17   #8
Registered User
 
Teknav's Avatar

Join Date: Jul 2012
Location: Texas - USA
Boat: Twin Otter de Havilland Floatplane
Posts: 1,838
Re: Discussion. Help me understand more in depth...clr! looks can be deceiving

As a general rule, the greater the keel's displacement the more stable the boat is and the slower as well.

Mauritz
Your opinion of me has no cash value!
__________________
Retired - Don't Ask Me To Do A Damn Thing!
Teknav is offline   Reply With Quote
Old 19-08-2013, 15:17   #9
Registered User
 
Wrong's Avatar

Join Date: Jul 2013
Posts: 1,702
Re: Discussion. Help me understand more in depth...clr! looks can be deceiving

Quote:
Originally Posted by boatsail View Post
That is the reason I was asking the question. I don't have a degree in engineering or physics. When I observe the two pictures I applied rationale.

If I were to draw a vertical line centered between the bow and stern of each boat, and pushed each "half" with equal force, what half would have less "friction" and therefore "give way" more. To me the answer is that the Norsea has less friction under the front half of the boat, so therefore would not be able to point as well due to the bow "blowing off" more than say the Cal I used in the example.

I don't know if I'm right or wrong, but figured that the knowledge base on here could probably give a more technical answer than mine and I could learn something from this thread and maybe others could too.

Plus, it was either this or start a gun thread.
Your choice is politically correct..

Google 'center of effort ' related to sail boats for a primer.

I own a Nor'Sea27 and she can be made to point higher by running the jib sheet inside the shrouds. There is a lot more than just keel configuration that affects a boat's ability to point higher into the wind.
__________________
Wrong is offline   Reply With Quote
Old 19-08-2013, 15:26   #10
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,369
Re: Discussion. Help me understand more in depth...clr! looks can be deceiving

I'm not seeing the CLR noted on the drawings.? But the short answer is no, the fullish keel wont point as high as the fin. The difference can be dramatic. (on a lucky day, trying hard, the HC38 in the avatar at left would tack through 120+ degrees..... in a chop more like 160!) it probably had a better "bite" on the water than the Norsea 27... (deep draft)
Having said that.. you get used to what you have and plan accordingly. Gentlemen never sail to weather...
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is offline   Reply With Quote
Old 19-08-2013, 15:27   #11
Registered User
 
Wrong's Avatar

Join Date: Jul 2013
Posts: 1,702
Re: Discussion. Help me understand more in depth...clr! looks can be deceiving

Quote:
Originally Posted by Teknav View Post
As a general rule, the greater the keel's displacement the more stable the boat is and the slower as well.

Mauritz
Your opinion of me has no cash value!
I was tempted to give a retort, but since you said - "As a general rule..." I'll pass.

I'll take stability (safety) over speed any day.
__________________
Wrong is offline   Reply With Quote
Old 19-08-2013, 15:29   #12
Registered User
 
Wrong's Avatar

Join Date: Jul 2013
Posts: 1,702
Re: Discussion. Help me understand more in depth...clr! looks can be deceiving

Quote:
Originally Posted by Cheechako View Post
I'm not seeing the CLR noted on the drawings.? But the short answer is no, the fullish keel wont point as high as the fin. The difference can be dramatic. (on a lucky day, trying hard, the HC38 in the avatar at left would tack through 120+ degrees..... in a chop more like 160!) it probably had a better "bite" on the water than the Norsea 27... (deep draft)
Having said that.. you get used to what you have and plan accordingly. Gentlemen never sail to weather...
Uh, oh. My competitive juices are starting to flow!
__________________
Wrong is offline   Reply With Quote
Old 19-08-2013, 15:33   #13
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,369
Re: Discussion. Help me understand more in depth...clr! looks can be deceiving

and........ whatever boat has the shorter waterline will be slower... regardless of keel. But the lighter one will accelerate faster to hull speed....
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is offline   Reply With Quote
Old 19-08-2013, 15:34   #14
Eternal Member
 
monte's Avatar

Cruisers Forum Supporter

Join Date: Jul 2011
Location: Australia
Boat: Lagoon 400
Posts: 3,650
Images: 1
Re: Discussion. Help me understand more in depth...clr! looks can be deceiving

the bow should't blow off on the full keel. The CLR is designed to balance the CE (center of effort) A quick glance at the rigs would indicate the CE on the full keel is further aft, hence the CLR is further aft (roachy main with boom to the transom) also the draft is less on the full keel. No reason it wouldn't point as high or as fast as the fin keel. If the CE and CLR aren't balanced you would have lee or weather helm and too far off balance would be unsailable. Adjust sails/reef to maintain balance. My guess is the full keel would track slightly better and turn slightly worse and be a b*tch to reverse.
__________________
monte is offline   Reply With Quote
Old 19-08-2013, 15:36   #15
Registered User
 
Wrong's Avatar

Join Date: Jul 2013
Posts: 1,702
Re: Discussion. Help me understand more in depth...clr! looks can be deceiving

Quote:
Originally Posted by Cheechako View Post
and........ whatever boat has the shorter waterline will be slower... regardless of keel. But the lighter one will accelerate faster to hull speed....
And, the boat with the longer water line length will probably cost a lot more too! May not want to take the lighter boat cruising though, eh?

Since Cheechako brought CLR into the discussion, see this: What is “lead” in sailboat design. Joe self designs a rig and finds something interesting. | Storer Boat Plans in Wood and Plywood
__________________

__________________
Wrong is offline   Reply With Quote
Reply

Tags
depth

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not 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 Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 01:11.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.