NavList:

Frank,

You mentioned:

"The gyros still matter, yes, but to what extent? I'm just asking. Is there really any time and money to be saved? It is my understanding that most merchant ships today seeking economic courses get into detailed ocean current and live weather analyses. The economy comes, not from steering a perfect course, but from avoiding bad weather, heavy seas, and those huge counter-current eddies from the Gulf Stream (for example). The details are up to the autopilot. You enter a waypoint, and let her go. The ship is a robot."

Rudder drag is a cost factor also. If the autopilot is working too hard and using too much rudder then the barrels per mile number will increase a bit. Optimal settings are probably automatic on todays modern units. Older autopilots had manual settings for rudder response and yaw allowance.

GPS course made good seems to wander and lag the compass as I just found out crewing on a friends boat a few weeks ago. We were making anchorage in zero visibility due to fog. I was watching the radar and the helmsman was watching the GPS chart plotter. The helmsman was steering a zig zag course using the chart plotter course to steer. I finally had him mark the course to steer on the magnetic compass when the anchorage was dead ahead by radar. That stopped the zig zagging. The radar also told me that no other vessels were in the area. Chart plotters won't do that unless radar and commercial vessel traffic GPS positions are integrated into it.

Greg Rudzinski

P.S. And yes the hand lead was at the ready just incase ;-)

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