Franko Manini
Well-Known Member
Folks,
I know the defacto standard for determining which chart of the Canadian Hydrographic Service's CURRENT ATLAS to consult when cruising is the Murray's Tables. However, there are other tables published online for southern Vancouver Island by a guy named "Borsboom" which you can get here:
http://borsboom.io/current-atlas-tables/
When I look at the two data sources they are vastly different. For example, let's look at today's data, starting at 07:00PT through 16:00 PT:
A bigger difference is apparent if you look at next week, say Monday, March 13th, same times:
I can understand that the two data sources use different algorithms to get the results they are looking for, but they are not even in the same ballpark. I would have assumed that the error between the two would result in a time shift of an hour or so, but these are remarkably different results.
Does anyone have any experience using the Borsboom tables versus the Murray's Tables? Are there times when one data source is better than the other? Have you been able to figure out what the differences are and if they matter or not?
Is this simply a matter of getting what you paid for, or is there some merit in both data sets?
I know the defacto standard for determining which chart of the Canadian Hydrographic Service's CURRENT ATLAS to consult when cruising is the Murray's Tables. However, there are other tables published online for southern Vancouver Island by a guy named "Borsboom" which you can get here:
http://borsboom.io/current-atlas-tables/
When I look at the two data sources they are vastly different. For example, let's look at today's data, starting at 07:00PT through 16:00 PT:
Murray's: 32-33-34-16-17-18-19-20-21-50
Borsboom: 33-34-35-10-11-12-13-14-22-23
Borsboom: 33-34-35-10-11-12-13-14-22-23
A bigger difference is apparent if you look at next week, say Monday, March 13th, same times:
Murray's: 64-65-66-67-68-44-45-46-47
Borsboom: 22-23-24-25-26-27-28-10-11-12
Borsboom: 22-23-24-25-26-27-28-10-11-12
I can understand that the two data sources use different algorithms to get the results they are looking for, but they are not even in the same ballpark. I would have assumed that the error between the two would result in a time shift of an hour or so, but these are remarkably different results.
Does anyone have any experience using the Borsboom tables versus the Murray's Tables? Are there times when one data source is better than the other? Have you been able to figure out what the differences are and if they matter or not?
Is this simply a matter of getting what you paid for, or is there some merit in both data sets?
