Hello,
I am a new sailor and want to understand how to chart a course. I understand that it is rather complex so I want to leave it simple for now. This is more hypothetical as I am not experienced enough to sail that far. I don't own any nautical charts so I have been using an app called OpenSeaMap. Let's assume that I want to sail from Port Credit to Niagra-on-the-lake (which I have included below). It is a distance of 27.66 nautical miles and it says I would need to sail on a true course of 127.46 degrees. However, I want to use a magnetic compass. The magnetic deviation is -10.1W. I understand that if the deviation is west, it is added to the true course, so I would sail on a course of 137.47 degrees on the compass.
Can someone tell me if that is even remotely correct? I have not accounted for other factors such as the tide.
Thank you!