Southern Spars Details 57m Carbon Rig for 39m Swan 128 BeCool

Southern Spars has published new engineering detail on the carbon rig developed for BeCool, the first Nautor Swan 128. The 38.98-metre sailing yacht carries a 57-metre rig package engineered to combine maxi-yacht sail area with the simpler handling required by an owner who wanted extended cruising without relying on a very large permanent sailing crew.

The project brought together Southern Spars, Future Fibres and RigPro across several countries. The mast was built in New Zealand, the 18-metre carbon furling boom in Spain and the standing rigging in Sri Lanka before the system was assembled and commissioned at Nautor Swan's yard in Jakobstad, Finland.

A taller mast replaced the square-top approach

BeCool does not use the conventional running backstays or square-top mainsail often seen on large performance sailing yachts. Southern Spars says the mast was made about three metres taller to recover the sail area that would otherwise have come from a square-top main, while allowing the yacht to retain a comparatively straightforward single-headsail arrangement.

The sail plan can use a gennaker, genoa or staysail, together with a self-tacking jib, furling boom and captive winches. That puts a large part of the handling load into engineered systems rather than manual deck work, which is central to making a yacht of this size manageable without requiring the entire crew on deck for every sail change.

The rig has to control very large sail loads

Southern Spars says the mast supports a 444m² mainsail, 402m² genoa, 369m² staysail and a 1,180m² asymmetric gennaker. Upwind sail area is about 846m², creating substantial compression, bending and rigging loads that have to be managed while keeping weight aloft as low as practical.

Future Fibres supplied AEROsix lateral rigging and ECsix fore-and-aft stays. Reducing mass high in the rig benefits stability and responsiveness, but the structural package still has to cope with the loads generated by a 136-tonne yacht carrying a performance-oriented sail plan in both cruising and racing conditions.

Building the rig across three continents created its own logistics project

The mast travelled from New Zealand to Belgium as deck cargo on a fruit ship before being transferred for the final leg to Finland. Southern Spars says the transport programme had to protect the finished carbon structure while also synchronising arrival with the yacht build and the specialist lifting equipment needed for stepping.

That logistical chain illustrates how a modern superyacht rig is effectively a separate major project within the yacht build. Design tolerances, transport supports, customs movements, yard access and commissioning all have to align before a mast that may have travelled halfway around the world can be stepped onto the hull.

BeCool shows the value of designing mast, boom and rigging together

Following delivery, BeCool sailed to the Mediterranean, appeared at Monaco and later competed at Les Voiles de Saint-Tropez and the St Barths Bucket. The yacht subsequently received the 2026 World Superyacht Award in the 30–39.9 metre sailing category, giving the integrated rig package experience across both cruising and racing programmes.

For Southern Spars, the engineering lesson is that mast, boom and standing rigging should be treated as one load-carrying system rather than separate purchases. BeCool is a useful example of that approach because the design had to reconcile high sail loads, lower weight aloft and easier handling without giving up the performance expected from the first Swan 128.