Foiling Nacra

Hi All,

Well, we may have been foiling, but not with a kite.  Stuart towed us off Raby Bay with the new Glidefree foils on the Nacra yesterday.  Not only did no one die (this is my son, Dominic’s, measure of success!), but

·         nothing broke (that’s rare),

·         nothing fell off,

·         no injuries,

·         we didn’t run aground (thanks for navigating, Stu),

·         the little 2 stroke worked well (not always a feature!),

·         take off speed was close to the predicted 9.5knots,

·         the wands (which sense height above the water and actuate cams which drive pushrods which control angle of attack of the main foils) seemed to work very well,

·         the initial setting for the rudder horizontal foils worked (even as predicted!) – take off on the main foils caused pitch up attitude which increased AoA on the rear stabilisers until they lifted as well – not much pitch up required,

·         foiling once up was reasonably stable with no rapid heaving or pitching and

·         importantly, the tow quick release worked very well!

Graham moved fore and aft to help take off.  We didn’t need to move laterally much for roll stability – though some pictures show our weight a fair way to starboard.  So even with no heeling moment from the tow (when directly behind the tow boat), the starboard, more heavily loaded, hull took off earlier than the port hull.  (The outboard was hanging out to port, but it’s not very heavy.)  We may need to check that the trim of the main foils is the same in both hulls.

We didn’t ask Stu to increase speed above take off speed as, had anything gone wrong, if we’d not been able to trigger the quick release (which requires manual activation), things  could have got ugly quite quickly.  I think we may have seen 12 knots briefly but we were mostly sitting around 10-11.

The goose on the helm clearly needs to learn more about using a tiller bar extension (a few lessons from you, AW, required here).  We rounded up a couple of times due to lack of helm control – mostly the helm was fine and the rudder is quite responsive.  But, fortunately, the quick release is even more responsive!  The round up under tow with hulls above the water and without a quick release could have ended worse than the big bear away when kiting off the Manly leads with AW a few months ago!  I think I’ll rig a steering wheel with high (but variable) frictional resistance…

We only towed once from out to the side of the tow boat (rather than directly behind) – this of course more accurately reflects the loads/dynamics we’ll experience when kiting.  We would have done more of this except that the tow rope was tied very low so was dragging a lot.  Suffice to say that, if anything, the ride felt better with that orientation and when we went straight through the wake from another boat going past the other way one of the benefits of foils became very obvious - we platformed straight over the waves and didn’t feel them!

Next outing will be with a kite.  We’ll be looking for 12-15knots and don’t plan to go out without a chase/support boat in the short term.  Unfortunately there don’t seem to be any good opportunities this week.  But when they arise I may seek some assistance.  Meantime, many thanks to

·         Stuart for towing

·         Anthony and Troy for riding shotgun with Stuart (and catching some photos/video – no doubt some of that will emerge soon enough)

·         Graham for crewing, shifting weight, jumping in the water to put the rudder pins in and, in particular, bringing his huge arsenal of practical aeronautical engineering experience to bear in design and setup

·         Ken and Daniel for doing the mods to daggerboard cases and rudder boxes and

·         Ian and Peter for the Glidefree foils – fantastic product.

Could be a huge summer of kite boating (I’ll report on the other project, a much bigger one but just a somewhat remote possibility at this stage, if it becomes more likely).

Best regards,