Thursday, April 23, 2009
A-o-A chart for outriggers
Here's a handy chart if you want to check the Angle-of-Attack of your riggers running surfaces as in front and rear sponsons and also the strut...
You need a flat set-up board with slots for the turn fin and rudder blade.
Draw up some straight base-lines on the top of the set-up board surface. Make additional lines 40, 50 or 60 mm in front of the base-line(s).
Put the rigger on top of the set-up board and align the trailing edge of the part of your rigger you want to check the A-o-A of to the base-line.
Measure carefully at the 40, 50 or 60 mm "length" the height up to your running surface (bottom of your sponsons etc).
The rear most part of your running surfaces must be flat or the A-o-A angles will not be right. (They need to be flat to make the boat run good also.)
If you for example have measured the strut angle at 40 mm and you get a reading of 0.8 mm you have a negative A-o-A of about 1.15 degrees...
Yes, it can be tricky to measure but U will figure it out... :)
If you want a high-res PDF of the chart to print out you need to mail me. e-mail