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

Go Back   Boat Design Forums > Design > Sailboats
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 10-27-2010, 08:32 PM
tranmkp tranmkp is offline
Junior Member
 
Join Date: May 2002
Rep: 78 Posts: 92
Location: Texas
Displacement - much more

Help me understand please - sailboat displacement - to me you have heavy, in the water (sticky) and you have light, out of the water (not sticky) Sticky being surface area. I suppose the goal is to find something in between..

So what would happen to say for sake of discussion, a westsail 32, we all know this boat - a hull speed heavy displacement boat with a comfortable motion, What would happen if we duplicated the 32 all in carbon fiber? If we kept the original ballast weight Im sure the boat would be much higher on her waterline. Ok, now we have to add additional ballast to bring her on her lines. Now with all that additional ballast you can add a taller more powerful rig. If you did that then wouldnt you have a boat with a very violent roll and motion? Suppose you kept the original rig with all the addiotional ballast - what would happen then?
Reply With Quote
  #2  
Old 10-27-2010, 10:19 PM
alan white's Avatar
alan white alan white is offline
Senior Member
 
Join Date: Mar 2007
Rep: 1211 Posts: 3,325
Location: maine
The boat would of course be stiffer. You can lighten any normal hull and put the weight back down low, given enough money and effort. Then you'd carry sail longer before reefing, and consequently the stresses on the rigging would increase, meaning the rig would require, on average, some upgrading to deal with those higher stresses.
Rolling would increase too.
Comfort aside, the boat would sail and resist capsize better.
Of course, you can do this to any normal sailboat.
You can throw money at anything but the same investment in a larger boat would be preferable because you'd get more space and more speed/safety as well all things being equal.
Reply With Quote
  #3  
Old 10-27-2010, 10:28 PM
PAR's Avatar
PAR PAR is offline
Yacht Designer & Builder
 
Join Date: Nov 2003
Rep: 3125 Posts: 9,408
Location: Eustis, FL
You'd need a stronger rig and several other not so obvious upgrades as well.
Reply With Quote
  #4  
Old 10-28-2010, 02:54 PM
tranmkp tranmkp is offline
Junior Member
 
Join Date: May 2002
Rep: 78 Posts: 92
Location: Texas
Ok, I think I get it -
Reply With Quote
  #5  
Old 10-28-2010, 07:00 PM
Paul Kotzebue's Avatar
Paul Kotzebue Paul Kotzebue is offline
Senior Member
 
Join Date: Apr 2009
Rep: 272 Posts: 244
Location: Encinitas, CA
The increased roll accelerations of your hypothetical Westsail 32 will be mitigated by the taller rig with more sail area. It is possible the modified boat will have a more comfortable rolling motion with lower roll amplitudes and less roll acceleration.
__________________
Paul R. Kotzebue, PE
www.pkboatplans.com
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
Displacement or Semi-Displacement Hull waynep Boat Design 24 10-05-2010 09:01 AM
Displacement ROBERTABC Boat Design 9 12-20-2009 05:30 PM
Displacement Design_1 Wiki 3 04-05-2007 07:47 PM
Displacement distribution Wardi Sailboats 22 06-03-2005 12:57 AM
Barge Displacement djreidt Boat Design 1 07-04-2004 09:04 AM


All times are GMT -5. The time now is 04:08 AM.


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