Martin, 

 I used a 5M x 7.5cm/3 inch x 3.2mm/1/8 inch Al al tube for the mast.  22mm x 1.6mm tubes for the yard and boom and 19mm x 1.6mm tubing for the battens.  

The 19mm may be a bit light.  Slieve suggested after I posted some of the pics in my album that he probably wouldn't use anything less than 25mm in any size of dinghy for stiffness reasons.  When I did get to sail the dinghy, I didn't notice the 19mm flexing but probably larger battens and maybe yard and boom would eliminate any worries in that regard.  Someone in another thread suggested 1mm per cm of batten length as a rule of thumb, which would make the battens required 30mm.

The tabernacle I made gave me 0.5M inserted or 10% of the overall length of the mast.   The 5M mast won't really allow you to install the full 13.5SqM/ 145 Sq ft of a regular Wayfarer.  I made it short enough to be able to go under a bridge between the club and the estuary which allows me to mount approx 10.5 SqM which for daysailing is probably more than enough.  

If you want more sail area, you could always add some wood at top, a la Arne's boats. 

As I wanted to be able to revert the boat back to Bermudan if the boat balance didn't work out with the Junk Rig installed, the tabernacle is made in such a way from box section steel that the mast slips down into the box section with some small wooden spacer taking up the slack.  The tube foot rests on a block of wood shaped to be supported by the  reduced size of the tabernacle which is just wide enough at the bottom to fit neatly into the original GRP tabernacle as designed by Ian Proctor.  

The balance of the boat seemed fine with my only problem in that regard being that the centreboard's friction brake was knackered and wouldn't stay fully down and most of the time was not fully down, which is one of the reasons I think my tacking angles weren't as good as they might have been.  Still made upwind against tide, but I think the bow was always being pushed a little downwind without the support of the board being fully forward.  

Will post some pictures  of the tabernacle into my album when I get a chance and find them.  

Regards, Dave.

Thanks David! What did you use for mast and batterns?

I know the feeling re time to try it out - took at couple of years before I had time to get my rig properly tested.

My dinghy sailing days are now more than half a century behind me now, but:

I remember borrowing a GP14 once, and thinking what an unpleasant, unmannerly, heavy thing it was, compared with my Enterprise.

I taught youngsters to sail in both Enterprises and Wayfarers, and they have similar characteristics, with just size to distinguish them. The Wayfarer is pleasant to sail, stable and forgiving, and I'd consider it a good choice for conversion. Only recently, I saw some unloved Wayfarers at a sailing centre in Stornoway, obviously abandoned in favour of more exciting boats, so it should be possible to pick one up.