Triple blocks

Looking to buy triple blocks for your sailing yacht? At 123Furling you will find an extensive range of triple blocks from leading manufacturers. A triple block has three sheaves and offers the highest mechanical advantage of all standard block types. This makes triple blocks essential for mainsheet systems and other heavy-duty purchase applications on mid-sized to larger sailing yachts.

What are triple blocks used for?

Triple blocks form the heart of powerful purchase systems on board. The most common use is the mainsheet system, where a triple block on the boom is combined with a triple or double block on the traveller. This delivers a mechanical advantage of 5:1 or 6:1, allowing even large mainsails to be trimmed with ease.

Triple blocks are also used for heavy cunningham systems, backstay purchases and other applications requiring maximum force with minimal manual effort. On racing boats, triple blocks are essential for fast and precise trimming under high loads.

Available types

Ball bearing triple blocks (BBB series) are available with D-shackle in swivel or fixed/swivel versions. The BBB 20, 25, 30 and 40 are compact and lightweight, ideal for yachts up to approximately 12 metres. The BBB 60 offers extra capacity as a fixed/swivel model for larger boats, with breaking strength up to 2000 kg.

Plain bearing triple blocks (PBB series) are designed for the heaviest applications. With sizes from PBB 50 to PBB 80, these blocks handle lines from 8 to 16 mm with safe working loads exceeding 1000 kg.

Variants with cam cleat and becket

Many triple blocks are available with integrated cam cleat, becket or both. A triple block with cam cleat is ideal as the end block in a sheet system, as the line can be cleated immediately after trimming. The becket serves as the starting point of the purchase and enables a higher gear ratio.

The combination of cam cleat and becket in a triple block is the most complete model. This block functions as the endpoint of the purchase, with the becket for the standing line and the cam cleat for cleating. This eliminates the need for a separate cleat block.

Mounting options

• With D-shackle, swivel: the block rotates with the load direction, prevents twisting
• With D-shackle, fixed/swivel: switchable via bushing for maximum flexibility
• With becket: additional attachment point for the standing line
• With cam cleat: integrated cleat for immediate line cleating
• With becket and cam cleat: the most complete model combining both functions
• Fixed model: for permanent attachment to boom, mast or deck

Building the right purchase system

A typical mainsheet system uses two triple blocks for 6:1 advantage. The upper block (on the boom) usually has a D-shackle and becket. The lower block (on the traveller) has a D-shackle with cam cleat. The line attaches to the upper becket, runs through all six sheaves and is cleated at the lower block.

For a lighter system, a triple block at the top can be combined with a double block at the bottom, yielding 5:1 advantage. This saves weight and is often sufficient for smaller yachts.

Why buy triple blocks at 123Furling?

• Complete range from leading brands for every yacht size
• Ball bearing and plain bearing variants
• All configurations: D-shackle, becket, cam cleat or combination
• Safe working loads exceeding 1000 kg
• Suitable for lines from 1 mm to 16 mm
• Competitive prices and fast European delivery
• Expert advice for complete purchase systems

Need help with your purchase system?

Putting together the right mainsheet or other purchase system can be complex. Contact us for personal advice. Our specialists are happy to help you choose the right combination of triple blocks, double blocks and single blocks for your boat.