These jammers were made for a small racing yacht. Each block has 4 receptacles for jammers and their control lines. The jammers themselves are made from 6061 Aluminum and the internal tapered ferrule from 316 stainless steel. The jamming ‘sleeves’ are from Technora – a high friction braided fabric sleeve that grips the rope, but does not damage it.
The blocks are very compact and the releasing line can be used to control the drop of the rope – i.e. if the sleeve is pulled fully loose, then the rope drops fast (e.g the spinnaker falls to the deck very quickly if single handed), if the sleeve isn’t pulled fully back, then a little fricton can help by keeping a slight tension on the line while the sail is gathered up by a solo sailor or short handed crew.
The design was tested in a 3D printed block first to ensure it worked correctly before machining the aluminum 4x blocks.
Two different sizes of jammers were made – one for lines approx 8-12mm in diameter, and another for 6-8mm lines, each using different sizes of Technora. The jammers are inter-changable in their receptacle in the blocks in case a new deck layout was required.
