At the very beginning of the feature, as the redcoat soldiers are marching into the island fort, briefly visible over the fort bridge are metal poles and a bar link fence clearly placed on the bridge for modern day safety purposes.
When Captain Sawyer orders Grog at high noon, he shouts "We'll splice the Main Brace!" which draws a cheer from his crew. In the modern age, the phrase "Splice the Main Brace" is a celebratory call before a drink; however, during the age of sail under its original meaning, the phrase was an order to undertake one of the most difficult tasks on-board ship involving splicing the principal line controlling the rotation of the main sail. The task was long and arduous and critically important for the safety of the ship. Thus, when Captain Sawyer gave this order, his crew would have been looking at hours of work ahead of them with no reason to cheer.
The HMS Renown is painted in the style known as the Nelson Chequer, with black and yellow bands and black gun ports, which is dated from 1803 when he took over command of the Victory, and subsequently painted his ships as such. The film is based in 1801. However, it is possible that Nelson was copying a ship he saw before his command of the Victory, and captains were allowed to paint their ships however they wished, so the Renown may have been the ship or one of the ships that may have inspired Nelson to create the Nelson Chequer.