Re: Near-shore tide what to expect. "Need some Guidance"
You may also want to read the following article
www dot ritchienavigation dot com/docs/ESRitchieLR dot pdf
It illustrates well the problem with GPS units when your speed over the ground is low (resulting from sailing at a speed close to the speed of the current). A GPS unit determines direction from position measurements. The GPS also determines the direction of movement of the boat, not it's heading, so if the current is carrying you sideways then the difference becomes obvious.
Keep a good compass on board ($50 - $80 is quite enough), cross check your heading taken from the GPS against the compass from time to time, and plot your GPS position on the chart. Any difference between compass heading and GPS will show up.
Are you single handing ? Do you have some sort of self-steering gear rigged up ? There will be times when you need, want, to take a break from helming.