The secret is how you load the bows and the main beam.
A pole that is extremely low will load the bows a lot when an "up force" is applied to the pole end and. A pole that is higher will create less loads on the bows.
Rule: Don't have the pole too low!
A pole that is way longer than the distance between the main beam and the bow will create a lot of compression of the pole, and that force will end up on the main beam. Rule: Don't use too long pole!
I use a 4.3 meter pole with 1.3 meter long support rods.
Check link for pictures:
http://www.webbo.dyndns.org/a-cat_sailing/spi//hakan
