TRC Good reply
TRC has it right but don't forget the ELT (Emergency Transmitter). I have made many cross water trips of +100Nm. I took 4 man life raft, ELT, crash kit (3ltrs water, survival gear, fishing line + hooks etc) all placed on passenger seat attached to life raft. Didn't wear a survival suite, just a life jacket, but I was in the Med in Summer. Would wear one over Irish sea.
The ELT will help SAR find you.
Good luck