Elementary sail boat script full perm

Now all the wise guys can examine, modify and apply this wind motor for their own purpose

Primy is a two prim boat made to present this motor
Primy contains one short script, just big enough to make Primy sail
The script is simple to read and understand, so it is a good foundation for big elaborate creations
The buyer gets full permissions to modify, copy and transfer prims and script

The core in the wind motor script is short and powerful
The core computes the forward driving force from the wind's force on the boats sail
It uses four vectors: boat velocity, wind velocity, sail normal and heading
All other variables, like: compass heading, speed, sail angle and apparent wind vector, are derived