On fractional rigs the forestay fitting is either fitted directly on to the mast or combined with the halyard
box (Seldén combi boxes). The forestay is often attached to the fitting with a toggle.
The stainless strap of the combi box wraps around the whole box and serves as a reinforcement that takes up the loads from the forestay. It also locks the sheave axles in the right position. The combi box penetrates deep inside the mast, allowing the spinnaker halyard to run freely past the genoa halyard. This solution substantially increases the durability and service life of the halyards.
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