Evelyn, I thought your "left the IOM on 13 December 1873" was unusual. They actually left from Plymouth, as did my ancestor from the IOM at around the same time.

Dilharree
Barque: 1293 Tons
Captain: R. McNeilly
Sailed Plymouth 13th December 1873 - arrived Lyttleton 11th March 1874

Originally a full-rigged ship built for trooping to India, the Dilharee, a composite-built vessel of 1293 tons, was rigged as a barque when she came to New Zealand in 1874 and 1875. She was a well found craft, and was pronounced admirably suited for carrying immigrants, as she had very roomy accommodation, having been built for a troopship. She belonged to Messrs. J. Lidgett and Sons, London. The first port she visited in New Zealand was Lyttleton.
Source White Wings Sir Henry Brett

Moore John 22 Isle of Man Farm Labourer, was listed under "Single Men - For Lyttelton".

The John Moore bapt Dalby IOM on 2 March 1851 could have given his age as 22 on 13th December 1873.
Where did you find his bapt/birth date?

Sue