Harken 51mm Thru-Deck High-Strength Block allows lines through the deck and bulkhead.
Harken's Lightweight, low-friction blocks with high-load composite bearings carry wire halyards and control line cascades. Side-load balls reduce friction from twists or unfair leads on 304-311. 300-303 has thrust washers. Blocks open to allow passage of swaged wire. Hard Lube-anodized sheave for strength and corrosion resistance. Cheek blocks include fasteners.