Full or fin keel? - Page 57 - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
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 > Out There > Cruising & Liveaboard Forum
 Not a Member? 


Like Tree241Likes
Reply
 
LinkBack Thread Tools
  #561  
Old 12-28-2012
blt2ski's Avatar
Senior Member
 
Join Date: May 2005
Posts: 6,770
Thanks: 0
Thanked 23 Times in 22 Posts
Rep Power: 10
blt2ski will become famous soon enough
Re: Full or fin keel?

Wolf,

Curious, is your B/D only using the "lead" in you keel? if so, you probably have a higher % than that, as one "should" IMHO include the rest of the keel as ballast per say. A swag would then be 4500lbs/15K = 30%. As you really have what is a precursor to todays T keels, but do to materials and knowledge of some material strength, many things were designs heavier than need be. With what is probably a 5'long, 6"wide, 1'high chunk of lead at the bottom of your keel, it behaves like a heavier fin keel from a stability point of view.

my 01 on the subject.

Marty
__________________
She drives me boat,
I drives me dinghy!
Reply With Quote Quick reply to this message Share with Facebook
  #562  
Old 12-28-2012
PCP's Avatar
PCP PCP is offline
Senior Member
 
Join Date: Dec 2004
Location: Portugal, West Coast
Posts: 16,201
Thanks: 21
Thanked 99 Times in 82 Posts
Rep Power: 10
PCP will become famous soon enough
Re: Full or fin keel?

Quote:
Originally Posted by wolfenzee View Post
My 30' full keel has a B/D ratio of about 25% (3800lb ballast/15,000 disp)
That is pretty low for a full keel and points to a tender boat. If you search and look at several full keelers you would see that the average is over 30%. They need more ballast because for the same dimension full keels had normally less draft.

what is the draft of your boat?

Regards

Paulo

Last edited by PCP; 12-28-2012 at 02:18 PM.
Reply With Quote Quick reply to this message Share with Facebook
  #563  
Old 12-28-2012
wolfenzee's Avatar
Senior Member
 
Join Date: Jul 2008
Location: S/V Waltzing Matilda, Port Ludlow, WA (NW Puget Sound)
Posts: 497
Thanks: 2
Thanked 2 Times in 1 Post
Rep Power: 7
wolfenzee is on a distinguished road
Send a message via ICQ to wolfenzee
Re: Full or fin keel?

Quote:
Originally Posted by blt2ski View Post
My previous generation by 3 or 4 Jeanneau, has 2400 to 6500 lbs of boat. With a 5.5' draft.

At the end of the day, if the boat works for your purpose, keel design and where the ballast is set at works, away you go! enjoy your boat! I'll still take my Jeanneau over an equal Catalina with a lead keel, I may heel a bit more, but I am faster in all but light winds!

Marty
A light weight disp fin keel will do better than my boat in light air (<5kt), but not by much, alot of heavy disp full keels can't get out of their own way in light air, my boat has always surprised me in light air. It doesn't take much for me to get to hull speed, 10kt wind w/main and working jib = 6.5kt. My boat starts to excel over the lighter fin keels as the wind kicks up, and when things get dicey I would have anything else. My "obsolete/antiquated" rig works differently and behaves differently with performance weeks over the years is quite satisfying, aside from performance, she has a style and grace that just doesn't happen in production boats. I respect "to each his own" as should everyone.
Reply With Quote Quick reply to this message Share with Facebook
  #564  
Old 12-28-2012
Banned
 
Join Date: Jan 2012
Location: British Columbia
Posts: 2,373
Thanks: 19
Thanked 33 Times in 32 Posts
Rep Power: 0
Brent Swain is on a distinguished road
Re: Full or fin keel?

Bear in mind the buoyancy of a wide, full length keel.
Reply With Quote Quick reply to this message Share with Facebook
  #565  
Old 12-29-2012
wolfenzee's Avatar
Senior Member
 
Join Date: Jul 2008
Location: S/V Waltzing Matilda, Port Ludlow, WA (NW Puget Sound)
Posts: 497
Thanks: 2
Thanked 2 Times in 1 Post
Rep Power: 7
wolfenzee is on a distinguished road
Send a message via ICQ to wolfenzee
Re: Full or fin keel?

Quote:
Originally Posted by PCP View Post
That is pretty low for a full keel and points to a tender boat. If you search and look at several full keelers you would see that the average is over 30%. They need more ballast because for the same dimension full keels had normally less draft.

what is the draft of your boat?

Regards

Paulo
My draft is 5' original ballast was 3200lb then 800 more was added totaling 4000, disp is about 15,000 (27%) still a little tender. Original design called for 13,200 w/3200 ballast (24%), but construction method ended up with a much heavier boat (still riding on design water line). It doesn't take much to get the boat over to 30degree heel, but once there it doesn't want to go any further (builder named the boat "Roll N' Go"), I know, I've tried, it's better to discover your boats limits before they get shown to you.
Reply With Quote Quick reply to this message Share with Facebook
  #566  
Old 12-29-2012
Senior Member
 
Join Date: Sep 2006
Location: Scotland
Posts: 2,267
Thanks: 0
Thanked 6 Times in 6 Posts
Rep Power: 9
Rockter will become famous soon enough
Re: Full or fin keel?

Get one of these (or similar)....


You can't beat a long keel in these conditions.
.
Reply With Quote Quick reply to this message Share with Facebook
  #567  
Old 01-03-2013
Senior Member
 
Join Date: Sep 2011
Location: Michigan
Posts: 228
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 4
BryceGTX is on a distinguished road
Re: German Yacht Magazine Article on Full vs. Fin Keel

Quote:
Originally Posted by PCP View Post
Sure, you are right as usual
Makes sense as I only post when you are wrong.

Quote:
Originally Posted by PCP View Post
The Jeanneau 30 has a B/D ratio of only 24%, the Jeanneau 33i has 32%

Most of these boats have or more draft or more modern and efficient keels that will make the difference in RM even more meaningful. To my knowledge there are no other 29/33ft as tender in the market as the Jeanneau 30.

Regards

Paulo
B/D can only be used as a measure of stiffness when the hulls are identical and the weight is proportional the same. Clearly not the case here.

And what do we care about the other boats you listed? They have nothing to do with the discussion at hand.

And clearly RM only is a measure of stiffness when the RM diagrams are identical shape. Clearly not the case here.

I can't imagine why you bring up the 33, when this test compares 30 foot and under boats.

So basically, your discussion of B/D has no meaning here. I suggest you learn a bit about what stiffness means.
Bryce
Reply With Quote Quick reply to this message Share with Facebook
  #568  
Old 01-03-2013
PCP's Avatar
PCP PCP is offline
Senior Member
 
Join Date: Dec 2004
Location: Portugal, West Coast
Posts: 16,201
Thanks: 21
Thanked 99 Times in 82 Posts
Rep Power: 10
PCP will become famous soon enough
Re: German Yacht Magazine Article on Full vs. Fin Keel

This was what was in question, this statement of yours:

Quote:
Originally Posted by BryceGTX View Post
Whoa.. a 30i is a particularly tender boat??? Clearly it is representative of a stiff production boat of the 30 foot size compared to the others.
Sorry.. you are wrong.

Bryce
Quote:
Originally Posted by PCP View Post
Sure, you are right as usual
The Jeanneau 30 has a B/D ratio of only 24%, the Jeanneau 33i has 32%, the Benetau First 30 has 29%, Dehler 29, 37%, Dufour 335 has 28%, Hanse 325 has 29%, A31 has 40%, the Elan 310 has 28%, Delphia 31 has 33%, Benteau Oceanis 25%, Bavaria 33 26%.

Most of these boats have or more draft or more modern and efficient keels that will make the difference in RM even more meaningful. To my knowledge there are no other 29/33ft as tender in the market as the Jeanneau 30.
and you say now about that:

Quote:
Originally Posted by BryceGTX View Post
Makes sense as I only post when you are wrong.

B/D can only be used as a measure of stiffness when the hulls are identical and the weight is proportional the same. Clearly not the case here.

... I suggest you learn a bit about what stiffness means.
Bryce
Here you have the hull of the 30i:



Here you have the hull of the 33i:



The Displ/lenght ratio is: 162.7 to 169.6

The very small difference in displacement/length has to do more with the much bigger B/D of the 33i then with any difference in the hull type or keel type. Both boats are even designed by the same NA.

Clearly it is the same kind of hull, the same kind of keel, the same kind of Displ/Lenght ratio.

How difficult is the check the data before posting?

Regards

Paulo
Reply With Quote Quick reply to this message Share with Facebook
  #569  
Old 01-03-2013
wolfenzee's Avatar
Senior Member
 
Join Date: Jul 2008
Location: S/V Waltzing Matilda, Port Ludlow, WA (NW Puget Sound)
Posts: 497
Thanks: 2
Thanked 2 Times in 1 Post
Rep Power: 7
wolfenzee is on a distinguished road
Send a message via ICQ to wolfenzee
Re: Full or fin keel?

Hull construction does have alot to do with it. My hull is 1" thick mahagony strip plank, glued and top nailed with 3" nails, screwed onto 2x3" double frames (which are bolted together with 3/8" through bolts) and 1/4" ceiling....to finish it off the builder also covered the boat with two layers of fiberglass. The weight is distributed alot more evenly.
B/D ratio by itself doesn't mean alot whole lot, it is simply "An indication of a boats stiffness or it's ability to resist heeling", some boats actually perform better when heeled (mine does best at 25-30 degrees and it doesn't take much to get it there) and some of weekend cruisers get nervous if there boat goes beyond 10 degrees so there are boats designed accordingly.
The height of the mast, sail area and beam all are necessary calculations here is a performance calculator for cruising boats: SloopIT - Boat performance calculator

Last edited by wolfenzee; 01-03-2013 at 03:20 PM.
Reply With Quote Quick reply to this message Share with Facebook
  #570  
Old 01-03-2013
Senior Member
 
Join Date: Sep 2011
Location: Michigan
Posts: 228
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 4
BryceGTX is on a distinguished road
Re: German Yacht Magazine Article on Full vs. Fin Keel

Quote:
Originally Posted by PCP View Post
This was what was in question, this statement of yours:

Here you have the hull of the 30i:

Here you have the hull of the 33i:

The Displ/lenght ratio is: 162.7 to 169.6

The very small difference in displacement/length has to do more with the much bigger B/D of the 33i then with any difference in the hull type or keel type. Both boats are even designed by the same NA.

Clearly it is the same kind of hull, the same kind of keel, the same kind of Displ/Lenght ratio.

How difficult is the check the data before posting?

Regards

Paulo
So I should check a 33 is bigger than a 30???? Who cares?

Quote:
Originally Posted by PCP View Post
They also chose for the comparison a particularly tender boat. If they had chosen the slightly bigger jeanneau 33i (much more stiff) I am sure the results would be different, not regarding comfort but speed.
Quote:
The 25/26 issue of the German bi-weekly Yacht magazine has a very interesting article comparing a full keel (Vindö 40, 31ft, 1971), a moderate fin keel with skeg (Hallberg Rassy 29, 1981) and a modern fin keel boat (Sun Odyssey 30i, 2008).

Paulo.. given that the three boats in question were 31ft, 29 ft and 30 foot.. why in the world would you suggest than anyone would compare these boats to a 33?

Who cares that a 33 is more stiff or faster or whatever.. clearly it is in a different class...
Bryce

Last edited by BryceGTX; 01-03-2013 at 09:29 PM.
Reply With Quote Quick reply to this message Share with Facebook
Reply

Tags
boat buying , newbee advice

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
Full Keel Vs. Fin or Modified Full Keel AjariBonten Sailboat Design and Construction 51 11-16-2013 03:52 AM
Full Keel vs. Wing Keel small boats Kyhillbilly General Discussion (sailing related) 4 07-26-2011 12:51 PM
4 ft draft, full keel, 30' and over? birdlives Boat Review and Purchase Forum 6 09-18-2010 12:00 AM
Older Full Keel boats JerryO39 General Discussion (sailing related) 30 06-09-2010 10:06 AM
Bristol 32'' full keel johnblsc Boat Review and Purchase Forum 2 12-13-2002 06:37 AM


All times are GMT -4. The time now is 12:36 PM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, 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.