Dario's Lab

Octave Marblehead Prototype Rigs: Progress on Spars

Carbon/foam sandwich jib booms were chosen to maximise jib efficiency and allow ‘finite’ adjustment arrangements using notches and pin/hole systems. The jib boom swivel line goes through a fairlead in the top skin of the yard and is anchored through the bottom skin. This is to maximise length for the required twisting of the line. Since the jib only rotates through approximately 60 degrees, this solution is adequate and a mechanical swivel can be eliminated.
Front fairings for the jib yards are lightweight plastic taken from knitting needles.
We are having similar plastic fairings machined so get in touch if you want to clean up the airflow at the front of your jib yards.
The final two pictures are of the backstay detail. Strops top and bottom are glued in place to eliminate chafe. The actual wire is mono filament fishing line and adjustment is via a turnbuckle at the aft end of the boom.