Sorry Gents, I checked with the staff in Rotterdam, Holland where an iron clad from the mid 19th century period is on display. It is everyones opinion that no netting or protective screens had been used inside any kind of gun turret during that period.
It was only later in the 19th century that screens had been hung across turret access to the magazines for protection from powder "flashover", a situation that is still possible today in ships and armored vehicles.

Splinters had long been known to cause terrible injuries in the days of wooden warships, but there wasnt anything that could be done to protect the sailors from the effects of enemy cannonballs and then shells exploding below decks.

Unhappily one sucked it up and kept on firing, Hogarth, a mid 18th century English artist published a whole series of paintings showing what ex-Royal Navy sailors looked like after being discharged from the effects of splinter injuries, crippled with minimal pensions, it wasnt a nice way to spend retirement.