GROCO Thru-Hull Installation Tool [THT-530] MAP Double Pulley with 12" military

Double Pulley with 12" military grade bungee for Double Rigging

For use on board commercial vessels

Outrigger Glass Rings (Pair)

Larger and more stable than the original

GROCO Thru-Hull Installation Tool [THT-530] MAP Double Pulley with 12" militaryThru Hull Installation Tool Thru Hull Installation Tool The Concept: THT 530 makes the installation of standard GROCO thru hull fittings possible by a single installer. Slide the thru hull fitting, flanged end first, over the tool. (It will stop at the proper step.) Tie a length of monofilament to the eye and place it into the already cut hole in the hull of the boat. Apply caulking to the flange of the fitting, and pull the fitting through the hole