There was considerable
discussion on the John
Welsford builders forum about the metric
system and metric tapes. Two prevailing opinions came
out of the exchange: 1) The metric system is much easier
to use, once you learn it, and 2) When building a boat,
you want your tape measure to have the same system on
both sides of the blade.
Unfortunately, it is
almost impossible to find metric-only tapes here in
the US. None of the retailers I tried had them, and
it is difficult to find them on the internet. We finally
found a manufacturer who makes them (Starrett) and bought
enough to sell.
As kind of a weird sidenote,
all the metric-only tapes we found had English blade
widths, as these do.