We’ve fitted riding sails on the backstays of many sailing designs (see our Offshore Cruising Encyclopedia for details), but have never thought of them in the context of a power boat. Until we came to Norway.

Here, all manner of craft, large and small, fit riding sails.

These vessels typically operate in short, steep waves, where it is uncomfortable and unproductive to lie beam to the waves. As designers we were dubious these small riding sails would be effective, although the local fishermen all say they work.

And then we started to look at the rigging details.

What follows is seen on many of the boats. The details speak to the functionality of the rigs. In this profile view note the angled pipe from the upper portion of the mast to the end of the boom which works as a topping lift and lazy jack.

A second pipe behind the “mast” provides a track for the gaff throat to ride on. The luff of the sail is also lashed to rings on this track.

And now the really interesting part of the design. The trailing edge is wedge shaped, held in place by the Y-shaped extensions on boom and gaff. This trailing edge reduces trailing edge flutter and creates more steering force from the small sail.

Most power boats dance uncomfortably at anchor. Some form of riding sail could go a long way towards alleviating this problem (maybe just a windsurfer type of rig).