Posted: Tue May 31, 2005 6:26 am
I dont think its so important to have the rudders at the 'optimised' angle when you are turning. As long as the two rudders are on the same side of the center of action, they both serve to push the stern in the same direction, albeit perhaps with different amounts of force.
I would think its most important to get them straight ahead at the same time for the least drag at straight ahead.
How is this for a Proposed test...
On a calm, flat water day. USe GPS for speeds please.
Put motor on post for locked ahead position. Make 6 mph inland, 6 kts offshore. Head for a landmark some distance away to hold a constant bearing.
Put each rudder in separately and check for loss of speed when pointed to landmark. Record each number. They should be the same regardless of rudder alignment to first order.
Now put both rudders in and check to see if the losses add up to the sum of the two individual rudders.
If the sums and the last configuration are equal, I would guess you are aligned well enough for government work.
Now take the motor off the post, and see if you get the same number. If you dont, then the rudders and motor need alignment. In a battle between the motor and rudders, I dont know who wins at 6 kts. It would take 10 Crays working in parallel to model this and my network is busy right now, trying to find the next perfect number after 27
I would think its most important to get them straight ahead at the same time for the least drag at straight ahead.
How is this for a Proposed test...
On a calm, flat water day. USe GPS for speeds please.
Put motor on post for locked ahead position. Make 6 mph inland, 6 kts offshore. Head for a landmark some distance away to hold a constant bearing.
Put each rudder in separately and check for loss of speed when pointed to landmark. Record each number. They should be the same regardless of rudder alignment to first order.
Now put both rudders in and check to see if the losses add up to the sum of the two individual rudders.
If the sums and the last configuration are equal, I would guess you are aligned well enough for government work.
Now take the motor off the post, and see if you get the same number. If you dont, then the rudders and motor need alignment. In a battle between the motor and rudders, I dont know who wins at 6 kts. It would take 10 Crays working in parallel to model this and my network is busy right now, trying to find the next perfect number after 27