Wellington needs minimum 6' tide for 19' boats 7' if you need the dock. The ramp ends about 10' back from the dock with a big drop that will remove your axle.
Captains cove needs 4' , but careful at low tide lift your leg before you hit the dock. There is a big hump of rocks and gravel at the end of the dock that you can't see.
Steveston can be used at any tide and is a shortest run to Sandheads I think opens at 6am maybe someone can confirm this
McDonald needs about 2' but lift your leg partially when entering the rock opening, there are random rocks unlucky people hit at really low tides. Opens at 6am