Course to steer.

[alant]

It ignores the tidal effect and keeps the vessel pointing in the direction set.

Tom.

If you calculate CTS, you will in effect, ferry glide a straight ground track to the target.
Simply pointing the bow at a waypoint/target, means you will be pushed sideways by the tide (whilst still pointing at the target), creating X Track error & different ground track. The error, as well as being shown on your plotter, can be found by calculating your Estimated Position (EP).

 

[LittleShip]

Alant, please read my original post on this, I think I have said that so others can understand, I'm not sure of what point you are trying to push.

Tom.

 

[henryf]

Just a point for anyone reading this who might be new to all this stuff.

The debate is what to do if you are crossing a tidal stream when heading for somewhere a distance away.

You can plot a straight line to where you want to go and stay on the line. The tide will try to push you off course to you steer into the tide so as to remain on your imaginary line.

If you are going to be on your journey so long that the tide will turn and push you the other way later on then you can be a bit clever let the tide take you so far off course, knowing when it changes direction it will bring you back to your imaginary line just as you arrive at your destination. This means you spend all your energy going forwards rather than "wasting" some of it battling the tide.

Here is my point: Be careful to remember that whilst your original plotted straight line might keep you out of danger your actual route taken when allowing the tide to take you will be some distance off that imaginary line. Make sure you don't meet any places of danger.

It is the same principle you use on your chart plotter for shorter journeys. Suppose you plot a course from Cowes to Lymington and get the auto pilot to track that course. Along the way you encounter a group of sailing boats having a race. You turn off the auto pilot and steer around them. When you switch your autopilot back on and ask it to track the course again the boat will turn to find the original route you plotted before heading to Lymington.

It is very tempting to simply press "restart XTE" (cross track error) as this avoids the seemingly unnesassary swing around to get back to your imaginary line. But if you press restart XTE your new course could potentially take you to a danger area or cause you to hit a mark you were previously going to miss. So make sure you have a look along your new intended course rather than just assume all will be ok because your original route was safe.

Sorry if this all seems a bit ladybird book one but I know lots of people browse these threads for information whilst not actually posting.

Henry