I have long wondered about the Crest’s cargoes and had erroneously suggested that she may have been taking on coal in Larne. In fact, Ireland has very little coal (although there were a few working mines there) and the trade in coal went in the opposite direction from the massive coalfields in the West of Scotland.
Thus the voyages of the Crest to and from Larne, proceeding there unladen and leaving with a load, led me to investigate what commodity that part of the North of Ireland produced that would have been required in Scotland, both on the Mainland and in the isles. I discovered this interesting reference to lime which was used for cement, whitewash and to neutralise acid soils.
Similarly, in November 1897 she took on cargo at Carrickfergus, taking it to Loch Maddy in North Uist and then (unless she swapped cargoes!) the remainder to Tarbert in Harris. My guess is that this cargo was rock salt from the vast mines as recorded in this BBC clip .
The other port in Ireland that was visited was Belfast but in that case it appears that goods were only being imported there for she appears to always have left unladen, collecting any cargo from neighbouring Larne.
Note: Here are the recorded voyages of 1896-1899: