Page "Carvel (boat building)" Paragraph 9

Traditional carvel methods leave a small gap between each plank that in the past was filled with any suitable soft flexible fibrous material sometimes combined with a thick binding substance.

This caulking would gradually wear out and the hull would leak.

Likewise when the boat was beached for a length of time the planks would dry and shrink so when first refloated the hull would leak badly unless recaulked-a very time consuming and physically demanding job.

The modern variation is to use much narrower planks which are edge glued instead of caulked.

With modern powersanders a much smoother hull is produced as all the small ridges between the planks can be removed.

This method started to become more common in the 1960s with the more widespread availability of fully waterproof glues such as resorcinal ( red glue ) and then epoxy resin.

Modern waterproof glues, especially epoxy resin, have caused revolutionary changes in both carvel and clinker style construction.

Whereas in traditional construction it was the nails that provided the fastening strength, now it is the glue. It has become quite common since the 1980s for both carvel and clinker construction to rely almost completely on glue for fastening.

Many small boats, especially light plywood skiffs, are built without any mechanical fastenings ( ie nails, screw bolts ) at all as the glue is in fact far stronger.