Announcements
  • A Call to AntarcticaOn March 10, 2009 at 13:43:19 French time, Skipper Rich Wilson and Great American III crossed the finish line at Les Sables d'Olonne. Race time: 121 days, 41 minutes and 19 seconds
  • Thank you for all of your kind notes, and for joining us on another educational adventure at sitesALIVE!

 


Keeping Great American III Upright

 

When wind blows on a plant or tree, it wants to tip it over, but its roots hold it upright. Wind effect
Similarly, when the wind blows on a sailboat, it wants to tip it over.
 
In order to keep a boat upright, there are three things to consider:

In small dinghies, you keep the boat upright by shifting the crew to the windward side to balance the boat and counteract the force of the wind trying to blow the boat over.

In big boats, there is a big heavy lead keel that hangs underneath the boat and acts as a counterweight to keep the boat upright. Wind effect
Even on a boat with a big keel, the crew may try to help with their weight. Wind effect
   
In a trimaran there is no keel. Instead, there are pontoons (also called floats or amas) on each side. The pontoons, like "training wheels" on a tricycle (a common trimaran joke!), keep the boat upright. Wind effect
   
When the wind blows against the sails of a trimaran, it tries to push the boat over, which tries to push the leeward float underwater. But that float has a lot of buoyancy, and resists, and keeps floating, thus keeping the boat upright.