The boat pictured in the FF Blog at the dinghy show is 3972 now out in Australia.
The under deck furler is a modified Allen Brothers Cat fitting. The boat also used a chute, the furler was rebated in to the underside of the deck so did not affect the spinnaker use at all.
We did have one or two teething problems with the line jumping the drum, but that was quickly resolved.
The new boat for 2013 is on the way and will most certainly be featuring the under deck furler once again.