There are some picture of a 9.5 foot rear beam with the down force foil shape built in at http://iceflyer.com/plans/95beam.html

I was worried about it side slipping more than an 8 foot beam but I tried it last Sunday on some fairly hard ice and it seemed to run ok (and when powered, was definately fast). So far, I like it but have not yet tried on the real hard ice where you have to have the runners real sharp. Im pretty sure that without the foils it would slip a lot more but Ive never tried this.

Regarding an earlier post about using a windsurfing rubber "hourglass" universal joint, we used these a long time ago and got away from them because they will distort like up to 2 inches laterally under good loads and you loose some sail lift because of this. They also make taking the sail off the boat more of a pain but.. I also didnt see one fail.

Wally Hall
Denver, CO

Wally

Why 9.5 feet and not 10 feet. The reason I ask is I have a 10 foot plank.

Roger

There was no good reason to go with 9.5, just seemed like a good number to start off with.

I used the 9.5 foot plank with the foils and it was definatly faster in lighter winds where the boat is more likely to hike and also on softer ice where the runners can really dig in.

However, in higher winds and on harder ice, the 9.5 foot plank (in my opinion) is definately more sensitive to runner sharpness than the 8 foot plank (given that both planks have the foils). My opinion is that I liked the 9.5 foot plank better (and it was faster) in lighter air but in higher wind on good hard ice, I prefered the 8 foot foiled plank.

Not wanting to carry around two planks, Ive now cut the 9.5 foot plank down to 9 foot and also added the 4.5 degree canting. Im completely sold on the usefulness of the rear foils on this boat so they are of course still in. My guess from sailing so far is that it will be a real nice comprimize for all conditions and faster than the 8 foot plank but you dont know until its been tried.

Wally Hall
Denver, Co