There's been a few interesting articles from designers recently that have found some instances where carbon boats can be made cheaper than equivalent glass boats. One article was about the construction of RIBs for the navy.

Admittedly, the main saving was in labour with a multi-layered laminate construction. The point is, please don't dismiss carbon because of perceived greater cost than glass, that is only taking into account material cost. Don't forget labour and life-time costs. Does anyone have data on life expectancy of carbon vs glass vs kevlar vs ply dinghy hulls? My gut feeling is carbon will come out on top with kevlar a close second, then ply (depending on maintenance and care) and glass last.