February 25, 2014 00:15
MacENC has a potentially very useful SailTimer function. As I understand it, this is licensed from SailTimer Inc and is a significant and valuable feature.
However, I get poor results with it as my Course Made Good diverges significantly from that predicted by SailTimer. I presume this is because my yacht's polars are different from the default values in the polars table built into MacENC SailTimer function.
Now I have tried recording my actual boat speed at various true wind speeds and angles, but this is very tedious and I get 'lumpy' and inconsistent results. I am searching for a way to create a better polar table for my yacht.
The iPolar app for iOS calculates a polar table based on given boat parameters (boat length, sail area etc.), but this is a theoretical table only. I haven't tried it.
SailTimer Inc have an iOS app SailTimer Charts Edition which has a learning mode, whereby it develops a polar table from experienced data. This would be an excellent way of gathering data for an individual yacht, and worth the in-app purchase cost. In my set up I have NMEA2000 feeding into MacENC, which sends NMEA data over TCP/IP to iNavX etc. However, according to SailTimer Inc, their app only accepts NMEA data using UDP. Their solution is to wait for their new wind instrument which will send data via BlueTooth to an updated version of their app. I do not want to get into installing a new and expensive wind instrument atop the mast just to get a polar table.
If MacENC could send NMEA data over UDP that would open up the possibility to use the SailTimer iOS app. Alternatively, MacENC has all the information needed to calculate polars, but this is not a trivial facility, not least because recording has to be selective to ignore inappropriate times - like motoring into wind. Given the pace of MacENC development, I see this as a non-starter.
Given the focus on iNavX development, recording polars there would make sense, and as iOS devices get used in the cockpit this would be the natural place to control when recording happened or not. However, building a polar table from a series of observations would, I guess, be a major development. [I wouldn't want to distract effort away from MacENC either!-]
Has anyone got a solution to this problem, or advice to offer?
Tony
However, I get poor results with it as my Course Made Good diverges significantly from that predicted by SailTimer. I presume this is because my yacht's polars are different from the default values in the polars table built into MacENC SailTimer function.
Now I have tried recording my actual boat speed at various true wind speeds and angles, but this is very tedious and I get 'lumpy' and inconsistent results. I am searching for a way to create a better polar table for my yacht.
The iPolar app for iOS calculates a polar table based on given boat parameters (boat length, sail area etc.), but this is a theoretical table only. I haven't tried it.
SailTimer Inc have an iOS app SailTimer Charts Edition which has a learning mode, whereby it develops a polar table from experienced data. This would be an excellent way of gathering data for an individual yacht, and worth the in-app purchase cost. In my set up I have NMEA2000 feeding into MacENC, which sends NMEA data over TCP/IP to iNavX etc. However, according to SailTimer Inc, their app only accepts NMEA data using UDP. Their solution is to wait for their new wind instrument which will send data via BlueTooth to an updated version of their app. I do not want to get into installing a new and expensive wind instrument atop the mast just to get a polar table.
If MacENC could send NMEA data over UDP that would open up the possibility to use the SailTimer iOS app. Alternatively, MacENC has all the information needed to calculate polars, but this is not a trivial facility, not least because recording has to be selective to ignore inappropriate times - like motoring into wind. Given the pace of MacENC development, I see this as a non-starter.
Given the focus on iNavX development, recording polars there would make sense, and as iOS devices get used in the cockpit this would be the natural place to control when recording happened or not. However, building a polar table from a series of observations would, I guess, be a major development. [I wouldn't want to distract effort away from MacENC either!-]
Has anyone got a solution to this problem, or advice to offer?
Tony