When the ship arrives at the island the lookout in the rigging calls out in Nagurski's voice (he is the usual Lookout), however at the same time Nagurski is seen at the helm 30 feet below the rigging.
The crew of the Kiwi, including officers, was seven men. In the stock footage of the ship leaving port (in this and other episodes) ten sailors are on the deck or in the rigging.