REPLACING TRAILER BUNKS
Replacing broken or rotting bunks on your boat trailer will help prevent hull damage.
Most boat trailers employ bunk boards to cradle the hull during towing and storage. In fact, many boats spend far more time on wood bunks than they do in the water, so these boards should be inspected regularly for excessive wear or broken lumber.
A bunk that snaps or falls off results in a loss of support that affects trailer balance and exposes the hull to the metal cross members, axles, bunk brackets and other structures that can gouge or puncture a boat.
If you see signs of a damaged bunk, replace it as soon as possible. With bunks that are more than a few years old, replace them all at the same time. The process is easy, but you will need to remove the boat from the trailer to take off the old bunks and install the new ones.
One approach is to first build the replacement bunks, then tow the boat to the launch ramp, pull the boat off the trailer and tie it up as you swap out the old bunks for new ones in the parking lot, if permissible.