Boat Design Forums  |  Boat Design Directory  |  Boat Design Gallery  |  Boat Design Book Store  |  Thanks to Our Site Sponsors

Go Back   Boat Design Forums > Community > Open Discussion: All Things Boats & Boating
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 11-28-2005, 08:53 AM
islander ken islander ken is offline
Junior Member
 
Join Date: Nov 2005
Rep: 10 Posts: 2
Location: channelislands
colvin design "althea" looking for info

Althea, 40'
Thomas Colvin design.
Hello everyone,
I was wondering if anyone had any experience of this drop/lifting (listed as swing) keel design.
I would really appreciate any info on handling, sea keeping abilities, as I am entering into purchase of same and still have at this point no idea how this boat will respond under sail and in heavy going. She is a new uncompleted project, so I am unlikely to find out prior to purchase without some research.
I would also be very pleased to hear of any experience, cruising any similar vessel.
She is 32' lwl 40 'overall (5'bowsprit) 11'4" beam, gaff riged ketch , 16,000lbs dis,
2',6" draft, keel up. 6',6" keel down. Ceder on oak laminate frame apoxy coated. Ballast unknown, the moving keel is made of oak and she has a 9oz main/mizen 8oz stay/gib on roller furling.
Do people cross oceans in these ? or do they belong in the caribbian and alike?
Any comment would be greatfully recieved.
PLease.
ken.
Ok, I think I may have posted this in the rong box, "but hay" at least I got here!
Reply With Quote
  #2  
Old 11-28-2005, 01:29 PM
PAR's Avatar
PAR PAR is offline
Yacht Designer & Builder
 
Join Date: Nov 2003
Rep: 2891 Posts: 8,798
Location: Eustis, FL
Centerboards/swing keels have been around on yachts for hundreds of years, many crossing oceans. The ability to handle deep water is more a function of the scantlings (how well she's built) rather then appendage configuration.

Deep keel, narrow boats are often preferred for heavy off shore work, but in light of the current trends of shallow bodied, wide stern craft making their way about, not as much a concern. Wide, shallow boats (particularly aft) offer off wind performance that can't be had with the narrow styles and it seems this is a trait that is here to stay. These shallow bodied vessels will be a handful in a good blow, but compensate with very high ballast to displacement ratios and a low CG.

Shoal draft craft (like the one you're looking at) use more form stability (beam) to help over come the higher CG and lower ballast to displacement ratio, typical of them. They aren't as well suited to heavy off shore duty, but a skilled crew can handle a well founded yacht in all but the worst conditions.

This is the key to successful deep water work, a well managed and skilled crew, willing to reef down when necessary and capable of performing the tasks asked in green water efforts. If you're looking for a long distance passage maker, then you should be looking at a solidly built design, intended for that purpose. If you require shoal draft then a fixed long fin (drawn out laterally) or a board of some type is necessary. The long fin will not have the aspect ratio to get her as high into the wind as a deep fixed fin keeler, but everything is a trade off. Since you have a gaff ketch, your windward ability will be limited anyway, so don't worry about the board.

Personally I dislike wooden boards (of any type or configuration) they can't be sealed (at least not for long) and cause trouble. This is one area a 'glass structure is ideal. Not a wood coveredwith 'glass board, but a completely 'glass structure, maybe containing some ballast if required. It's unlikely to swell, split, check, tolerates dings and nicks much better, plus a number of other difficulties, commonly found in wooden boards. I'm a big wood fan (ask anyone here), most of my work is in wood, but boards and rudders should be something else, in my opinion.
Reply With Quote
  #3  
Old 11-28-2005, 01:47 PM
islander ken islander ken is offline
Junior Member
 
Join Date: Nov 2005
Rep: 10 Posts: 2
Location: channelislands
just to say a quick thankyou for your reply Par, i've had to carry this to long without help, you have pointed out somethings that had'ent even crossed my mind, she is heavy built though but i've not inspected her for myself yet.
Reply With Quote
Reply



Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
College for Naval Architecture Archive Education 15 04-07-2008 01:42 PM
Master in yacht design ambas Education 26 05-11-2006 02:47 AM
Looking for the right path to design and build ben_morel Education 44 11-24-2005 04:51 PM
Westlawn Shool of Yacht Design michal Education 9 03-07-2004 09:11 PM


All times are GMT -5. The time now is 08:33 AM.


Powered by: vBulletin Copyright ©2000 - 2012, Jelsoft Enterprises Ltd.
Web Site Design and Content Copyright ©1999 - 2012 Boat Design Net