The H010 and H029 Ball Socket Swivel Bases allow blocks to swivel freely and pivot to a 45° angle. Bases may be fitted with springs but withouth them the block still won't hit the deck. Select blocks carefully as the maximum working load of either base is often less than suited blocks.

The H061 Stanchion Mount Base attaches blocks to 7/8" (22mm) or 1" (25mm) stanchions and pulpits and is often used to lead furling lines to the cockpit. Allows blocks to swivel and pivot for fair leads.

Use the H1573 Midrange Stand-Up Base with Midrange blocks. The low-profile design is ideal as a mastbase halyard lead block. Combine the H1573 with single Midrange ratchet or fiddle blocks. Doubles and Triples will fit the H1573 but their Safe Working Loads are higher than the base.

Stand-up base accepts a 3/8" post and 3/16" pin. Works with all Ronstan Series 40 blocks with posts (ie. not loop heads) and with only the singles with posts from Ronstan's Series 50. Base is a rhombus, 51mm x 75mm (2" x 2 31/32") angle-to-angle.

Use these to turn blocks into stand-up blocks. The LW29904046 suits 40 and 50mm blocks. The LW29904050 suits 60mm blocks. The LW19811000 suits 60mm Synchro Blocks. The LW19821000 suits 72mm Synchro Blocks. The LW19831000 suits 90mm Synchro Blocks.