Haisborough Gat is a restricted navigational passage which requires a high degree of positional awareness. Manually recording and plotting fixes at 5 minute intervals would be almost impractical for an OOW on the bridge alone. However, when this measure was discussed by the master and the 2/O, no consideration was given to increasing bridge manning levels. During the passage through the Gat, the master and lookout should have been on the bridge, which would have allowed the 2/O to focus on position fixing and track monitoring.