High Zappto I am using 2 jigs I have made One For The Vanguard the other for the Granado, they are constructed using box section aluminium
obtained from B & Q here in the uk, its sold in meter lengths, the finger grips are made from 1/4" steel strip with nylon facings, the units are very good at
keeping the keel straight during frame assemble and first planking, the Granado frame had a very slight curve after removal from the box, and due to the jig's alloy back bone this has now been corrected. the design enables you to complete the first planning nearly down to the keel before removal required. I have included a few
photos, hope this may be of help. Mike