Bit slow to the discussion.
I have sailed two 14s with the underfloor shute. one had a sock inside the shute, one didnt, not sure the reasoning for each.
Cockpit is obviously alot clearer, bonus.
In waves it seems that you just fill the shute with water and the spinnaker keeps the water in there. obviously deck design
When it is light the drain at the back can be submerged (might be the transom lead) filling it up again.
Both boats were permanetly closed, i,e, not removeable. The Canadians and americans are more keen than anyone else.
If you have heard of the Killing 3 14 they have some different takes on the outting the boat together (rear gantry is a large OD carbon tube) and it has the underfloor shute too.