Easy way to add mast to canoe?

Im currently building a 12' canoe, and I'm thinking of adding a sail later on. What would be the easiest way to add a mast to the boat, but still have it removable. I've already got a pretty good idea of what to do for the rudder and leeboards, and have them removable.

 

A self standing mast would be easiest. The sail plan with the shortest spars would be a gunter or a sprit rig.

 

I learned to sail on a canoe I converted. The 16 ft canoe was fiberglass and the seats had two aluminum tubes that dropped down from bolts at the gunwales with a fiberglass seat pan. I drilled a hole in the bow seat and glassed a block of wood to the keelson for a mast step.

The rig was a 40 sq ft lateen rig from a Sunflower sailboat. Same as the styrofoam Snarks. The sail was probably made of nylon rather than dacron, and the spars were aluminum tubes. The rig was smaller and much lighter than, say, a Sunfish's.

For leeboards, I made a thwart with endplates and carved the boards from 3/4" mahogany to a cambered airfoil shape, and mounted them to the end of the thwart with the flat side to the outside. The boards tapered to a handle on the top that was raked back 20 - 30 degrees. A bungie ran from the board handles forward to the seat to retract the board, and a line with a hook ran aft to be secured to the center thwart when the board was down.

The gunwales on this canoe were a rounded aluminum extrusion, so it wasn't practical to try to clamp onto them. So I got an aluminum sliding door track that was shaped much like an I beam and cut it into two pieces that ran from the bolts holding the bow seat to the center thwart. The leeboard thwart was then attached to the rails using U-bolts so I could position it fore and aft to adjust the balance. Once I found the right location, I never moved it again. So I could have mounted some brackets on the side of the canoe and dispensed with the rails. But one objective of the rig was to be able to return the boat to its original condition for paddling trips, and the only permanent modification was the hole in the bow seat and mast step.

I never did get around to making a rudder - just steered with a paddle. The boat was well balanced, so there wasn't much too it. When tacking, all I had to do was pull back the pendant on the windward board and hook it on the twart. A bit of a sweep stroke and she turned through the tack. Released the windward board pendant and the bungie pulled it up and held it out of the water.

I did notice the canoe twisting visibly when the wind was up, so some diagonal braces would not be amiss.

With a 12' canoe, I assume you're single-handing it and there isn't a bow seat or a center thwart. But you could add a twart to serve as the mast partner. The rest of the rig could be similar.