This spinnaker crane attaches to the masthead truck without any additional holes or fasteners. All of the parts shown are included. Just remove the stock clevis pins for the forward halyard sheaves, forestay, and the original spinnaker halyard pin and replace them with the longer pins provided. The crane moves the spinnaker halyard block forward. The block is now farther away from the forestay. The bail allows the block to position itself for a fair lead regardless of what tack or point of sail you're on.
Some customers have found it convenient to use the top plate of the spinnaker crane as a mounting platform for their wind instrument transducer. You must drill and tap the holes to match your transducer's mounting hole pattern.
Fore & aft: about 3-1/4"
Athwartships, port to starboard: 2-1/2"
Width, inside: about 2-5/16"
Includes three extra long clevis pins, 1/2" diameter X 2-5/8" grip.