Originally Posted by RBEmerson
That seems to be a response based on faith rather than on facts
Another area of instrumentation error that implicates the log that many don't seem to be aware of is in wind
speed and direction, both true and apparant. If this is dependant on the log and compass
heading rather than the GPS then the whole of the vector sum of set, drift and leeway is an error in it as is the log error too. The set, drift and leeway can be a substantial error so gives the situation of the wind
instrumentation only tending towards accuracy when set, drift and leeway are nil, leaving only the still likely to be important error in the log.
This becomes especially important on race
boats if sailing to polars. A friend, who has unfortunately unexpectedly died, developed professional nav systems and high end sailing instrument systems for racing
sailboats which addressed both the navigation
and wind errors introduced by avoiding use of the log and compass and using GPS.
The electronic charting system that I use for navigation
seems to discard the log and compass heading information when calculating wind and uses the GPS SOG and course over ground but I have not had the incentive to delve into confirming that. Why I think it is so is that the wind vector rotates aimlessly when the boat is stationary. I don't know how common that is with other ECS's as again I have not had the motivation to check.
Note nowhere have I suggested a log is redundant, can be a salve to the body to see speed through the water
but hopefully some will see that the faith that is put into it for navigation and wind is misplaced now that there are far more accurate ways of navigation based on GPS.