To meet the requirements of a double-spreader rotating mast, four custom carbon spreaders were designed and built for Fram. The original aluminium spreaders were discarded in favour of a lighter, integrated composite solution that combines structural efficiency, Dyneema rigging attachment, and deck lighting.
A wing mast for Fram – Part 2 building the spreaders
The two spreaders supplied with the new mast were unsuitable for Fram. In addition, the mast needed to be fitted with a double set of spreaders. Although Ian Farrier provides construction drawings for aluminium spreaders, I decided to build the spreaders from carbon.
The design consists of two carbon tubes, a Corecell foam infill, a mast-end plate shaped to fit the spreader shoe, and an outboard end plate incorporating a low-friction ring. The Dyneema standing rigging is fully captured by this ring.
The spreader shoe transfers loads primarily through two bolts. Between these, I added a third bolt and machined the end plate to fit tightly against the mast. Internally, the mast is sufficiently reinforced at this location.
A self-built spreader also offers the opportunity to integrate deck lighting cleanly. Initially, I purchased round light fittings, but these proved unsuitable once the beam angle and structural impact were considered. Positioning the round fittings optimally would have weakened the spreader excessively. As a result, a more elongated light fixture was selected. The unused round fixtures were repurposed as floodlights mounted on top of the upper spreader.
This photo gallery of about 35 photo's shows the complete construction of the carbon spreaders: from replicating the spreader shoes and reinforcing the carbon tubes, through lamination, vacuum bagging and Corecell infill, to final fitting, painting and installation on the mast.
