If I remember the old dusty tomes rightly, you rigged the nets only on the dies with the greatest risk if on a mooring (no doubt after bending a line on the mooring to veer the ship about in tide, wind, and current.).
That would let the boat booms on the opposite side be rigged and used--and the accommodation ladders, too.
On anchor, probably is when the full kit of nets might be out--maybe. Probably the nets were raised and dipped for boat operations in that case--just enough to let the boats in and out.
But, we cannot discount the professional skills of Bo's'n'smates the world over. MacGuyver has nothing on a couple CPO and a deck gang. Never has, never will So, a spar probably would be rigged as a guyed jib derrick from the stern to sway boast over the nets. Would probably depend upon just how important the Commodore or Admirals mail and dispatches were.