Whilst at Deptford, the rig of the Grenville was altered from schooner to brig, as Cook thought that her sailing qualities would be improved by the change, and she also received a thorough overhaul.

In Admiralty Bay, which he entered to refit for the homeward voyage, the sails were found to require a thorough overhaul, for, as Banks says, they: "were ill-provided from the first, and were now worn and damaged by the rough work they had gone through, particularly on the New Zealand coast, and they gave no little trouble to get into order again.