A passing reference in a splendid article [“Ireland and the Black Atlantic in the eighteenth century” in Irish Historical Studies vol xxxii no 126, November 2000, which you may be able to read online] by Nini Rodgers alerted me to a proposed Limerick enterprise of which I was previously unaware. Dr Rodgers’s source was Faulkner’s Dublin Journal of 27–30 November 1784, to which I don’t have access, but it was probably the source for stories in the Derby Mercury of 2 December 1784 and the Chelmsford Chronicle of 10 December 1784, both of which are in the British Newspaper Archive.
The Derby Mercury put it thus:
Extract of a Letter from Dublin, Nov 27
There is at last some Probability that a vigorous Effort will soon be made for the Establishment of a West-India Trade, that may become a national Object in this Kingdom; an African Company is now projecting to be established in Limerick, where six Vessels will sail annually for the Guinea and Slave Coast, and from thence to the West-India Islands, whose Produce they will bring Home. They will at their own Out-Fit in Limerick take on board Linens and Cottons, plain and printed, Tallow, Horns, &c. The Out-Fit of these Vessels will not exceed 3,500 l. There is nothing against this Project but the Explanation of the Act of Navigation, which our Parliament alone has it in its Power to rectify.
Apart from minor points of punctuation and capitalisation, the Chelmsford Chronicle story is the same.
Limerick was, Nini Rodgers says, the first Irish port to promote a slaving enterprise. The African Company would have traded its linens, cottons, tallow and horns for slaves, sold them in the West Indies and bought sugar with the proceeds. I don’t know whether it ever got off the ground.
In general, though, Irish merchants profited from the slave trade not by buying and selling slaves but by supplying provisions to feed the slaves on the islands, allowing the plantation owners to devote their land entirely to growing sugar.