CTS across tidal water with B&G

[Oodles]

Hi,

Does anyone know if it’s possible to get a B&G Zeus 3 to calculate a course to steer across tidal waters? At the moment I can do this manually on paper by adding the tidal vectors for the passage using assumptions of speed. Using the Zeus I can get it to provide a rhumb line but that’s not at all ideal. What I’d like is to see the (for example) classic S shape on the chart and to be able to follow that to get the quickest route.

Many thanks

 

[AntarcticPilot]

Hi,

Does anyone know if it’s possible to get a B&G Zeus 3 to calculate a course to steer across tidal waters? At the moment I can do this manually on paper by adding the tidal vectors for the passage using assumptions of speed. Using the Zeus I can get it to provide a rhumb line but that’s not at all ideal. What I’d like is to see the (for example) classic S shape on the chart and to be able to follow that to get the quickest route.

Many thanks

If you STEER the rhumb line, your course over the ground will follow the S-shaped pattern you describe - there's no need to steer it, it just happens! There are programs that will provide tide corrections - SavvyNavvy comes to mind, and I think some modern chartplotters provide that function.

 

[James_Calvert]

It would be clever though, to have the plotter project the S curve as the intended track, and measure the cross track error from that.

Wouldn't it?

 

[AntarcticPilot]

It would be clever though, to have the plotter project the S curve as the intended track, and measure the cross track error from that.

Wouldn't it?

I suppose that doing that would mean that the autopilot wouldn't be attempting to steer back to the rhumb line, resulting in an inefficient course. But I guess that I'd be concerned that tidal atlases don't tell the whole story; there are often local back-eddies that the broad brush of tidal atlases don't capture. Averaging things over the whole track is going to work better than the piece-wise corrections that would be needed to work out the actual track over the ground. In principle I think it's a good idea, but I wonder how practical it is.

When I'm using the autopilot for a long passage, I tend to set it to a bearing, not to a track.

 

[Pye_End]

Hard to duplicate paper chart planning on electronics.