Hi Et
I think major factor is/was a lack of awareness of the relationship between filler coats and the light strips. It seems to me everywhere I read about filler coats I see the perceived dangers of adding weight and little importance placed on the fact that this is what gives us a watertight boat....

Also I found the lighter strips I'm using (5mm) quite hard to control and weren't butting together quite as good a previous builds which is where the pinholes came from (I think).

As per Bill's comment - workshop is indeed unheated but we are not talking US cold - temps around 12-14 deg C in Ireland

Worth commenting as well is that filler coats I added this weekend were done outside in nice sunshine and applied longitudinally along the hull following the strips which seems to have given the resin a better chance of going where it's needed. Previous coats were applied transversely in workshop

Resin is SP 106 which I always used and find it very reliable....

The ski weighing in at 14kg so far so can't complain about weight - have cockpit fit out to complete and varnish as long as I don't sand off the filler coats and cause more leaks!