unfortunately you do
No.
You don't need a passport to travel between the UK and the Republic of Ireland.
yes you do im Irish
No
yes, because the republic of ireland is a seperate country from the UK you will need a passport to go there.
Yes. I've never been asked for any form of ID travelling from NI to Scotland by ship. Its generally regarded as a domestic ferry trip. But if you are flying you need to check with your airline as to what form of ID they require. Ryanair etc require a passport for all of their passengers
no - it's an internal UK ferry trip
depends where your coming from, see the related link.
No. They are both in Ireland, so if you are in Cork legally, then going to Dublin does not require any additional documentation. You may have needed a passport to get to Ireland in the first place. If so, then keep it with you when travelling around Ireland.
Generally you will need a passport to visit Ireland. As a general rule, you should always get a passport when travelling internationally. The fact that you grandmother is Irish, does not mean you can travel to Ireland without any passport. You may actually be entitled to get an Irish passport. See the related question below for details of documents needed to visit Ireland.
Do u need a passport from scotland via dunegal going by ferry
Yes you do. Whether you are leaving the UK by air, ferry or Channel Tunnel you need a passport and you also need one to return.