Transition Rig

The concept
Other ideas


Recent addition to this website: a rotation within the mast that I call pronation/supination

Transition Rig - folding mast and sail
inspired by the wings of bats and birds


The idea for the Transition Rig came 30 years ago, and I now have successful prototypes for smaller craft such as windsurfers, kayaks, canoes, and dinghies. I believe that this simple-to-use sailing rig that can be folded away when not required has a worthwhile place amongst the many other types of sailing rigs that are around today.

Other people are focusing on how best to obtain a blistering performance, with wing-sails and hydrofoils currently in the spotlight, yet there are many of us who sail for pleasure and appreciate a sail and mast combination that is easy and practical to use.

Think of an umbrella: we carry it around folded until it rains, and then open it in a few seconds to give us shelter. When the rain stops, we fold it away again so that it doesn't get in the way. The Transition Rig follows a similar logic - when you need a sail you can raise it quickly and gain power from the wind. When the voyage is over, or if a storm strikes while you are at sea, you can quickly fold the rig away.

When you have a mast that is jointed to enable raising and lowering, other things become possible. You now have a variable-geometry rig with the potential to change its shape in use and according to conditions. No doubt you have watched birds soaring in thermals and along hillsides facing the wind and marvelled at the way they continuously adjust the shape of their wings in gusts and lulls. The Transition Rig gives the same possibilities for shape-changing in use, but I have discovered that this is a much harder goal to achieve than the folding. I have spent a lot of time experimenting with the variable-geometry aspect, but there is still a long way to go.

If you are someone like me who likes making things in the shed, or students looking for projects in the realm of sail and rig design, or entrepreneurs looking for an exciting concept in the water-sports arena, I hope you will find this website helpful. If you are a designer who can see ways of improving the rig or its appearance, let's have a go at that. If you are an engineer who understands how to program electric motors and use limit switches and proximity switches, that would be particularly helpful at this time since I am in the process of making an automated version of the Transition Rig.

As the days and weeks go by, I shall be adding items to this website, so please revisit from time to time. As a starting point, I have summarised the concept and started to record the versions I have made so far, together with a proposal to use Transition Rigs on larger ships. I have begun to add a few short videos to illustrate the ideas.

My name is Richard Dryden, and you can contact me by e-mail at


The concept Versions Joints Sails Other ideas

 site last updated: 19/02/17