Over on Off Center Harbor there's a video called Designing with Mock-Up Patterns & Prototypes, A Motor Mount for a Caledonia Yawl wherein they make an electric motor mount for a double-ended Ian Oughtred design. It's behind a pay wall, though.

Unlike the Skerry, the Caledonia Yawl has a very robust sternpost that acts as an achor for one end of the mount. But the video may be good inspiration.

Keep in mind that CLC does custom design for hire. The same experts who designed the boat kit could design you a professional grade motor mount. You could contact them and ask.

Happy New Year,

Laszlo

While I don’t have direct experience with a Skerry, I have mounted an  outboard before on a double ender before

There are two approaches that folks typically take.

The first approach is to create a beam that the motor can be mounted on somewhere off the side of the boat.   This can be done as a temporary fitting or something more permanent.  For example, when we had double ender sailboats that we needed to temporarily motor, we would place a beam across the top of the hull and lash or otherwise secure it to the hull for the transport.   A more permanent side mount is also possible. http://forum.woodenboat.com/showthread.php?222581-OUTBOARD-MOUNTING-for-DOUBLE-ENDER   has some ideas.

The second approach is to create a motor box that you could mount in front of the centerboard (or behind if you were so inclined).  In this case you would open a hole in the hull, and build a box back up from the hole that was big enough for your motor and also prevent the boat from leaking through the box.  

Both approaches are pretty straight forward to construct….albeit a bit of work.   A lot of how you approach this and the particulars of construction depends on the motor size and weight, where you want to position it....aesthetics and how temporary or permanent you want this to be.

h