Parking an eight is a challenge - it's long and not very manoeuvrable.
Helpfully the RowIntel crew have a great explainer video How to Dock a Rowing Shell.
What we really like about this is that he sets the wind and tide/current direction and shows clearly how you can use them to help you dock the boat exactly where you want!
Getting crew members to help with the docking by holding water moves the pivot point of the whole crew and can enable tighter steering. Adding an oarsman on the opposite side rowing while the other side holds water to check the boat speeds up the pivoting. What is key is that you use athletes at opposite ends of the boat - so if 7 holds water then it should be 2 rowing on (not stroke or 6). And if stroke is holding water, use bow and 3 to row on.
You need to learn what the effect on the boat is of having athletes in the stern hold water versus those in the bow. It affects the pivot point of the boat and the rotation of the shell away from the pivot. More leverage can be had if the checking motion is sternwards of the pivot point, in general. But you should try out using different ways of moving your boat so you know how the boat moves and how skilled and strong your crew is (different crews are different).
- Plan your course a long way out so you don't have to make abrupt changes
- Use tape to mark the centre position of your rudder (when it's straight)
- When using the rudder the stern is what moves left or right which makes the bows appear to turn left / right
- Use different seats to hold water or row to change your pivot point and make your boat easier to turn.