Dave — The photos of the bow chock and painter may be a bit misleading. The winch line doesn’t come over the bow — it goes thru the hole in which a bow-eye would be installed. The aft side of the hole is reinforced with a yellow pine doubler. The 3/8” winch & tow line is made fast (on the boat side) with an eight-knot — and the bitter end is reeved thru a hole cut in the breast hook just aft of the bow-line chock.
For towing, the line going out forward thru the chock is used to hold the bow down tightly against the trailer’s bow roller. The other end (going out thru the stem) ends with a bowline loop for the winch hook.
Here you see the line going over the bow, down under the wooden stabilizing block, up thru a hole in the block, and belayed to a cleat. To make a snug and tight hookup, the winch is made slack — then the stop knot is pulled tight up against the underside of the breasthook, and while pushing down on the bow, the down haul line is pulled tight and belayed to the cleat. At that point the slack is taken up on the winch line — which pulls the stop knot down and close up against the aft side of the stem. Now the winch is tightened to proper tension — and the bow is held tight against the bow roller from two directions at right angles to each other.
The combination of the stopknot and bowline loop knot (on opposite sides of the stem) assure that the 3/8” line is always with the boat. It’s bitter end (up thru the hole in the breasthook) serves as a short painter. But more useful, it’s a terminus for a much longer painter needed at launch to keep the boat from getting away from the dock after launching off the trailer.