Leaks:

A very common place for leaks to develop is in the rabbet between the garboard and keel, just under the mast. This is due to the downward thrust and working of the spar. If a boat persists in leaking there, lengthen the mast step so as to distribute the strain over a larger space. Our modern plank-keel boats are liable to develop cracks in the plank, which will only leak when underway, and are difficult to discover, as they close up when the boat is at rest. If the leak is bad it can be readily found by hauling the boat out, filling her bilge with water and watching where it drips out.