I'm not familiar with a Lynch boat but is it designed for lake and river fishing rather than the sea?
Can you post some photos?
As with any boat, its not the boat its the conditions, however ...
Tackling the sea, and Galway Bay is very open to the ocean, is a very different task to trolling or drifting on Lough Ree.
Please please
never go fishing on the sea (or anywhere else) alone. Get a buddy to fish with you. Don't become a statistic.
Fly fishing boats are designed to operate in a very specific way. They are designed to drift slow, sit into the water and give their anglers a stable platform. They tend to be narrower in the beam (width) than sea boats. This is often described as their length to beam ratio. Beam is critical to stability at sea. Critical. Long narrow boats do not perform well at sea.
Currachs (which are long and narrow) do perform well, however this is because they are so light and have no keel and a round hull - they are designed to rise over the waves and do this exceptionally well, but are no place for a novice sailor.
You also need to look at the freeboard - the distance between the waterline (on a calm day) and the top of the gunwale - which is often far shorter on fresh water boats than in sea boats. Boats designed for fresh water and in particular fly fishing are vulnerable to being swamped if sea conditions deteriorate. Think very carefully about how to get back to the pier and how long it will take you at top speed. Again fly fishing boats are not typically designed to plane, i.e. rise up above the water so that they can move a lot faster. Some of the modern designers have taken this on board (it cuts down on fuel costs) but a long narrow boat at sea? Not ideal.
Don't imagine for a second that you will never get caught out when at sea. It happens to the best of us. You must be prepared. I am sure Jim and others will offer excellent advice on this. If its not a lake boat, my apologies for my ignorance!
Stay safe.
Join a sea angling club. You will have no shortage of people ready to go fishing with you (and share the costs).
Hope this helps...
Kieran
PS: just started on some larch planks for my own boat, which will be modelled on a Scattery Island two hander (currach). Madness.