Swivel with NMP block. Can be used in the head of a sail for a 1:2 halyard for example.
TyeTec NMP blocks (NMP= No Moving Parts") are designed for use in between the loop thimbles and loop blocks. The fixed part is spliced through the central opening or suspended, and the block is secured through the milled slots with stitching or with a simple cable tie to prevent twisting.
NMP-S block (S=Sail): for mainsail reefs. The NMP-S block also has an additional slot for attachment flat on the sail. Dyneema webbing is used to attach it to the sail.
Hand stitching through the outer slots will prevent the block from twisting. The webbing
should not be sewn closer than 2xB to the block, to lower the compression force .
NMP-D block (D=deck) for mounting on the deck, on the mast, on a track or slide.
The NMP-D block is fixed through the central hole with a stainless steel screw. Two smaller screws on the outer radius hold the rope in position against the sheave. Without these two scews, the block can be used as a deflector, just flipping the line behind it.
The Max Working Load specified relates to the horizontal force on the block with its lower face on the deck. The MWL can be lower for different types of attachment and in relation to the stiffness of the deck.