Mingming II’s Sea Trials on the Crouch

»«Tuesday 8th October 2013

It is not a straightforward matter to convert a Bermudan rigged yacht to junk rig. It requires a complete re-design of the mast position and sail plan. However hard one works at getting the balance of the yacht correct, by locating the centre of effort of the sail at an appropriate position relative to the centre of lateral resistance of the hull, there are no guarantees of success; there are simply too many variables to take into account. Add to that a radical design for the sail itself and the possibilities of getting things wrong are further magnified.

Mingming II’s sail plan was specifically designed for the light winds of the Arctic summer. As the junk rig can be reefed in a matter of a couple of seconds, with one hand and without leaving the hatchway, it lends itself perfectly to carrying an excess of sail; hence Mingming II’s towering rig.

The sea trials are designed to answer two fundamental questions – how does the boat balance, and what are the appropriate sail settings for different weights of wind? Alongside these are the questions of speed and good manners. Does the yacht handle easily? Is she light and responsive to the helm?

Although there are still many things to discover, I feel I can now say with some confidence that Mingming II has exceeded all expectations. As she is not finished inside, and is in nowhere near full cruising trim, she is still very light. Nonetheless I have been amazed at her turn of speed, especially in light airs. More importantly, she balances almost perfectly, with just a hint of weather helm. This makes life a lot easier for the self-steering gear; it is not required to correct imbalances in the boat as well as hold a course. She answers the helm immediately and without complaining; she doesn’t gripe to windward.

Inevitably she needs reefing early; this was part of the plan. I suspect that in full cruising trim she will hold her canvas a little longer. Her specially cambered sail panels give a lot more power upwind than the flat sail of Mingming I, and a narrower tacking angle. I had expected an increase in average speed of 0.5 to 0.75knots, but it looks like it will be more than this, possibly over 1knot. This will extend my cruising range for a 60 day voyage by about 1500 miles, somewhat more than anticipated.

So far Mingming II has only sailed on the Crouch. I will have to take her to the Arctic and back, and sail through a good storm or two, before I can be really sure that she can outperform her elder and more petite sister. She has a lot to live up to.

Roger Taylor