Spy photos

It is an over-rotating section, but you can pre-set exactly how much over-rotation you want - it is a set and forget system unless conditions change drastically.  98 x 42mm Eliptical derived from NS14 type sections that were imported.  So far so good but we have more development ahead.  But this was Halo's first competitive outing and we are very very satisfied with the way it went.  We would have been happy to start anywhere really provided we learnt something about its relative performance - which we did in buckets. (However from 926 ? - in my dreams QMSC....;-)   Halo is however much faster than the Blaze, the rig points exceptionally high, is extremely tolerant to sheeting angles and seems to be amazingly efficient and easy to use with no real vices found yet. (But we will be changing the standing rigging a bit to stiffen up the bottom 1/3rd).  In summary -  No fuss just a lot less drag and a lot more go.      

We are planning a production section if the trials continue to go well.  This will be made available to the market beyond Halo -  I even got a couple of private enquiries from other classes after the 'Bloody Cold'     

Blaze720    

Yes - but difficult to factor for this against 'regular' masts.  Nearest over-rotational masts on a dinghy are on Tasars in this country and they are also comparable with camber induced rigs I would guess.

Dan Holman kindly sent me a copy of the PN prediction spreadsheet he uses today.  Substituted in sail area, leverage and helm weight changes etc for Halo against his standard Blaze data and it suggests around 1020 but that has no 'efficiency' adjustment of the sort required. 

Not going to speculate on Halo's eventual PN but it will get below that figure for sure (for the target average 100kg+ -guys), and better helms may get considerably more speed around the course out of it than the average one.  The intention however was not speed to the exclusion of other objectives, nice though extra speed always is.  The objective is to end up with a refined modern  alternative class for larger helms.  To succeed it has to be an excellent all-rounder in any breeze and above all be fun....   

Blaze720

Of course, all catamarans use them as well...

Over the last 40 years a huge number of masts have been tried in the NS14 class, both over-rotating and fixed.  The section that the Halo uses is by far and away the most popular and successful mast in the class, and is more modern than the squareback tasar section.  In fact it is very much like a scaled down A Class or Tornado section.  As Mike says, they are very stiff fore and aft, and very flexible sideways.  This means that you can tune the flex of the mast to the gustiness of the prevailing wind by varying the amount of rotation.  In general the mast is pointed into the apparent wind, but if it is gusty you can rotate it less and the top of the mast will bend off.  Another advantage of this is that in normal set up (pointing into the wind) the mast is slightly felxible on a beat, and much stiffer on a reach.  This gives the sail much more power on a reach than you can get with a fixed mast, which if it is allowed to flex upwind will also flex on a reach.  The reduced drag of the over rotating mast also allows the boat to point higher on a beat and creates less heeling moment.  And it isn't heavy, my aluminium section is lighter (per metre) than the Proctor section used on 200s, Fireballs etc.

Incidentally, some of the carbon wing masts used on the A Class cats are actually more flexible in the fore-aft (long) direction than the sideways (narrow) direction, due to the fibre layup.  At least, this is what I am told.