Sag into a much faster shape?

I have had a great comment on my last blog post about the Norfolk One Design, not sure who ChrisJ is and what links he may have with the class, but this is what he has to say...

ChrisJ says:

"...The Norfolk One Design, being 14ft long, was originally able to race competitively against International 14s. Now that they are twin-wired, carbon, wide, modern rigs etc that is no longer the case.

Many of the Norfolks were made before World War II. The story goes that during the war they were all laid up for 5 or 6 years. After the war, as people got back into sailing again, new ones were being built to the same original design. BUT the new ones were slower than the old ones, which had managed to sag into a much faster shape in those 6 years!..."