I wish this was an easy answer. It would be nice to be able to say; “Just set your speed at X knots and everything will work out great.” Sadly, it doesn’t work that way. Sometimes I think fairway speed, as the old cliche goes, “is more art than science.”
I do know this, if you are pushing a bow wave, you are way too fast. From the office, I see it all the time, and cringe. One small hiccup and … ouch.
Your wake starts as a small ripple coming off the transom. As you move faster, the wake moves forward along the hull. As it moves forward, it gets bigger. As you are motoring down the fairway, check your wake. If it has moved as far as amidships, slow down! Look at the boats in slips beside you. If they are moving past quickly, slow down.
Which brings up the other side of the question. How fast is too slow. You have to be going fast enough to have good rudder authority. You have to have enough speed to hold your location in the fairway? You have to have enough speed to make a safe turn into your slip. The only way to figure out if you have the right speed is to try it out ahead of time in a similar but safe area.
Docking into an upwind slip generally requires a bit more speed than a downwind slip because you must have enough rudder authority to get the bow up into the wind. Try this before going into the fairway. Find a nice safe place to test conditions. For example, if you plan to dock in a slip in the “Silver Fleet” upwind row, try turning into the wind in the open area of the marina well to windward of any slips and/or boats. Using the buoys in the marina as reference points will help you gauge your speed. How much speed does it take to have good control of your turn? Any slower is too slow … any faster is probably too fast.
Remember. No two dockings are the same. Review your L.O.T. every time you bring a boat in. Fairway speed is one element of Transition.