Built for the Carron Company, to transport coal and iron ore to their foundry near Falkirk, and to take product from it to the docks on the Clyde and Forth. Also presumably used as a feeder vessel for their steamship services out of Grangemouth to London.
No 4 was originally built by Thomsons as an un-powered, or "dumb", lighter but a Loyds List report, and Lloyds is normally accepted as 100% reliable, of 1881 (below) does clearly classify her as a "steam lighter". One has to assume that she had been engined in the intervening years although no records that I have seen make specific reference to this.
Lloyds List of Friday March 25th 1881 records:
"Grangemouth, March 24, 11.40 a.m., GLENCOE (s), of and for Middlesborough, from Grangemouth (pig-iron), and Carron lighter No.4, of Grangemouth, from Bo'ness for this port (general cargo), were in collision in Carron Roads last night: the steam lighter sank immediately, the crew barely having time to get on board: GLENCOE has put into Bo'ness Harbour with bows stove, but extent of damage unknown."
This appears to have been a quite separate incident to the one involving "Glencoe" and Carron's dumb lighter "No 2" later the same day. "No 4" appears on the 1881 census, taken on the night of the 3rd April, with crew on board in Grangemouth docks and so it does look as if she was salvaged within a week or so of her sinking. A claim for £1324 covering the loss of the lighter and its cargo was settled in full by the insurers.