Southern's Foiling Moth rig explained

Nice article copied from Sail-world.com


Southern's Foiling Moth rig explained

''Mr Foiling Moth' Rohan Veal flying with a Southern Spars rig at the 2009 Int Moth Worlds'    Sean Trew (Pacific Fog) ©

During the recent CST Moth Worlds held in Oregon, Southern Spars new rig design was put to the test. Results are in, and 10 of the top 20 competitors were using Southern Spars kit.

So what makes up the Southern Moth rig?

The key objective was to produce a rig that would fit the range of sailor weights now common in the Moth class. After a collaborative R&D effort between Southern Spars and North Sails that included analysing mast stiffness characteristics and current sail designs in the class to the nth degree, it was decided that two spar options would be produced.

Southern Spars developed its two masts: the standard P1 mast suited to all sailors, as well as the aptly named Phatboy mast for the heavier sailor. The rationale for developing two different masts is that larger sailors apply more force through greater righting moment and consequently force masts to bend more than a smaller sailor. Therefore, it made sense to design two masts with different levels of stiffness that would bend equally regardless of the size of the sailor. This evens out the playing field for a larger sailor by allowing them to make better use of a standard sail design.

Both spars are two-piece masts made from high modulus carbon - laminated to give the most consistent bend possible; they are joined with a spigot. The mast plugs are made of lightweight Acetyl plastic, while the spreader attachment is carbon and the stay attachment is a small lightweight alloy fitting – presenting less windage than the previous mast.

The new high modulus oval boom is approximately 25% stiffer than its predecessor making vang changes more decisive; it also offers less windage and weight. The mast package has absolute minimal weight at approximately 2kg fully rigged.

Southern’s Composite Rigging have also developed EC6 carbon stays for the Moth. The new stays are 1.9mm in diameter and weigh just 29g apiece. This is considerably lighter than both PBO and wire rigging, which weigh in at 44g and 128g per stay respectively.


by Brenna Pringle   5:59 AM Thu 15 Oct 2009