Laminated
Colin -All the wooden tillers I've seen have been made from a laminated product. I would imagine that they're made from a lay-up of hardwoods such as maple, oak, teak, etc. A single piece of wood probably lacks the strength of a laminate. If, however, you aren't concerned with it lasting more than a season or so, I would suspect you could use just about any hardwood of the correct thickness. West Marine used to stock replacement tillers, however I couldn't find any on their website.Fair winds,Steve