Passenger lists usually ended up at the destination post, so not very many available at this end. I suspect the ship would have been UK registered, probably Liverpool where the Black Ball Line was based, I think if any maritime court proceedings took place these would have been where the ship was registered or possibly London.
Ginnane is not a common surname in Co. Limerick, just three with that spelling listed in Co. Limerick at the time of Griffith's Primary Valuation, all in Prior's Land townland in Killeely civil parish. The valuation took place around September 1850 in this area. Killeely civil parish is located in the northern suburbs of Limerick city, north of the River Shannon. For reference the town and parish of Shanagolden is located abt 40km to the west of Limerick City. The first is a John Ginnane leasing a house and yard at Cashel's Lane, Prior's Land from an Ann Trousedell, the next a Michael Ginnane leasing a house & small garden at Tyrell's Lane Prior's Lane from the Earl of Limerick, and there's a nother listing for a Michael Ginnane also at Tyrell's Lane leasing a house and small garden from a Thomas Banks - this last entry looks like it might be a duplicate... unless there were two people of the same name on the same road.
A more common spelling variation of the surname seems to be 'Guinane' and a search of Griffith's using this spelling shows nearly 30 matches, including several in Shanagolden civil parish (AskAboutIreland).
The Tithe Applotment records took place around the late 1820s early 1830s and these show a number of Ginnane entries around the county, including two in Shanangolden civil parish - a Thomas at 'Monavaha Glen' townland, and John (Jno.) at 'Mountdavid' townland. Unfortunately the lack of early Church of Ireland or Catholic records for Shangolden will make it difficut to prove any family connections with certainty, it seems fairly likely that one or both of these are related to your Margaret....
MacLysaght's "Surnames of Ireland" notes Ginnane as a West (Co.) Clare surname which is also quite numerous in North Tipperary and King's Co. (Offaly) where it is often spelt as 'Guinane'