[MHml] Cat Rudders Toed In?

[Paul Nudd]

Glenn Brown wrote:
> Paul Nudd wrote:
>> Half a degree? You can measure that accurately?
> 
> Sure, with 2 people: Just line up one rudder roughly fore-and-aft and 
> measure the difference between the center of the leading and trailing 
> edges.  For rudders that are 6" (254mm) front to back, 1 degree is 1/8" 
> (just over 3mm)
-------------------------------------------
So half a degree is 1.5mm, quarter of a degree is 0.75mm"
Accuracy required for half a degree to be meaningful is +- 0.75mm
If this is not possible then it is either 1 degree or 0 degrees.
Best I can measure over short distances is +- 0.5mm
over 5 metres I would be happy with +- 2mm
First find centres of leading and trailing edges of both rudders, 
accurate to +- 0.5mm 4 measurements resulting in +- 2mm then measure the 
2 distances accurate to +- 2mm each
Cumulative accuracy of the difference (after 6 measurements) is +- 6mm
So, if I measure 1.5 mm difference it may be anything between 7.5 mm and 
negative 4.5 mm
Am I right?
I think I'd do better 'eyballing' it.
I think the best way is to set it on the move, motoring in flat water, 
adjust crossbar until both rudders show best flow.
PN