Seldén automatic ratchet blocks in the ARB45 and A60 ranges, 45 mm and 60 mm sheave diameters with composite or aluminium sheaves, in swivel, soft attachment and cheek mounting options for dinghy mainsheets and spinnaker sheets.
How to choose
An automatic ratchet block switches from free-turning to ratchet mode as load increases, holding the line without the sailor needing to cleat it. Unlike a manual ratchet block where the sailor operates a switch, the automatic version engages on its own. The switchover point is adjustable with an allen key on all blocks in this collection, so the sailor sets the load threshold to match their conditions and preference.
The first choice is sheave size. The ARB45 has a 45 mm sheave and suits lines up to 8 mm, covering mainsheets and spinnaker sheets on smaller and mid-sized dinghies. The A60 and A60+ have a 60 mm sheave and suit lines up to 10 mm, providing lower friction under higher loads on larger dinghies and two-handed boats.
Within the A60 range, choose between the standard composite sheave (A60) and the aluminium sheave (A60+). The aluminium sheave provides more grip on the line, which is useful when running thinner mainsheet or sheet lines where the composite sheave gives less bite. If your sheet is at the upper end of the 10 mm range the composite sheave is sufficient. If you are running a finer line and want more positive ratchet engagement, the A60+ is worth specifying.
For mounting, choose between swivel/fixed, soft attachment and cheek options. The swivel/fixed shackle locks at 0° or 90° and suits transom or boom-end mainsheet fittings. The soft attachment versions mount with a soft shackle or Dyneema lashing, saving weight and eliminating a metal contact point. The cheek versions mount flush with three M5 screws and are directional: the clockwise version is for the starboard spinnaker sheet turning block, the anti-clockwise version is for port.
What's in this collection
The ARB45 is a 45 mm automatic ratchet block for lines up to 8 mm, suited to mainsheets and spinnaker/gennaker sheets on smaller dinghies. It is available in two versions: a composite sheave swivel variant (404-401-01R) and an aluminium sheave variant (404-360-51), the latter providing more grip on finer lines. Both include a swivel lock for 0° or 90° fixed shackle position.
The A60 is a 60 mm automatic ratchet block with a composite sheave for lines up to 10 mm. Available as a swivel/fixed variant (406-350-51R), a soft attachment version for use with a soft shackle or Dyneema lashing (406-350-54R), a clockwise cheek block for the starboard spinnaker sheet quarter (406-350-55R), and an anti-clockwise cheek block for the port spinnaker sheet quarter (406-350-56R).
The A60+ is the aluminium sheave version of the A60, providing more grip on thinner lines. Available as a swivel/fixed variant (406-360-51R) and a soft attachment version (406-360-54R). Both suit lines up to 10 mm.
