I'm thinking my way through a hull design for a boat (about 30' and ideally run betwen 70 and 80 mph) and i'm struggling with a few issues concerning the strakes. Does anybody have any thoughts on how to determine the placement of the strakes, the size of the strakes or the number of strakes for the boat.

Also, I have read and am currently receiving conflicting explanations about the purpose of strakes. I would appreciate your thoughts.

Thanks

Id go ask the guys over here: http://boatdesign.net/forums/index.php?

Divide the distance from the chine to the center of the keel, and divide equally by the number of strakes you want. They are lifting strakes. They also take the place of the chines as the boat comes up out of the water as speed increases. Older designs don't have full strakes to the transom. At the higher speeds now-a-days, the strakes are no longer hitting the water, therefore having no effect on handling. This usually results in "chine walking", or the boat tipping from side to side at speed.
Of course, the previous ramblings are my theory. Take them with a grain of salt, if you will.

Know why they have strakes on boats? To keep the laborers from sliding off while they are sanding the plug.........

This is really bad, ..... but I just can't help myself...... would that make them strakes and ladders.

More strakes mean more lift.more strakes mean more turbulence on turns. Placement is usually equal across the bottom. Less strakes near the transom gives the drive a cleaner stream of water.All designs have their downsides.Compromise on what you are after,top end speed, handling or soft ride. Its hard to have your cake and eat it too.