Small Boat 57 & 75 mm Flip-Flop Blocks Small Boat Flip-Flop blocks pivot around the line axis to keep line close to the deck. Hinged construction allows for various lead applications. Lightweight, machined 6061-T6 aluminum cheeks pivot on fiber-reinforced plastic chocks. Free rolling ball bearings, sheave and sideplates are UV stabilized with black additives for maximum protection. Ratchamatic® versions roll freely in both directions under low loads and automatically engage a ratchet mechanism as loads increase, giving sailors a holding power of up to 15:1. The ratchet engagement can be adjusted to a higher or lower load depending on the sailor’s strength, sailing style and system usage. Reversible cam arms adjust and lock in a wide range of positions for crew accessibility and accommodation of changing lead angles.