In my last post I talked about how the wing dragging was being caused by insufficient angle of attack on the main foil, well I was wondering how the heck that could have happened (again). To setup the angle we rolled the bottom of the boat upside down and set the hull up so it was level at the centerboard case.

As it turns out, that wasn’t the right thing to do. The centerboard position of my boat is a little further back than the current Hungry Tiger, as the measurements were based on the ones that Andrew Landenberger was using successfully at the time. The fact that the case is further back, means that I have not set the foil angle relative to the waterline, but relative to a point on the curve at the back of the hull.

This has resulted in a setup error in the order of somewhere up to five degrees in the wrong direction. At the nationals last Christmas, it must have been something like 10 degrees the wrong way ! No wonder VR is hard to get out of the water !

The diagram above shows exactly how the error occurs. The blue line is parallel to the waterline of the boat, whilst the red line is the one we used to set the boat level and configure the angle of the main foil. You can clearly see that there is a significant amount of setup error that has occurred, especially when we are trying to get around +ve 2 degrees of lift on the main foil.

A good thing about this is that after the issues at the nationals, I have deliberately left things in a semi-finished state do I can make exactly these sorts of adjustments on the boat. This also shows that if you are planning a foil conversion or building a new boat getting the angles correct (or having them adjustable) is absolutely critical.