Actually, Brest.
But not with a Mac. My Tibato was O.K. on a 6 foot well formed sea, nice long big round waves, but on a non-formed sea, the bottom was hitting the water so badly, I had to reduce speed when upwind motoring. I mean, down to 2 knots. I was thinking of fleeing with a little genoa back to where I was coming from and into a storm... But then, the waves became bigger the sea got formed, so I could continue and accelerate to Etang du Nord. My crossing took me 50 hours 20 minutes, including 15 hours of sleep. The wind was calm at night and I wanted to cross under sails!
Under sails, upwind on a 6 foot sea, 25 knots wind was O.K. solo, but would not have been with a lady. She would have cried. 30 degrees heel, with occasional turn-arounds. No time to be distracted. Peeing at the wheel in a jug before pouring overboard. My Doupette was hiding in the cabin and sleeping!
Downwind, 9 feet seas with 30 knots winds, is limit. The boat surfs like creasy. You need a little genoa ahead, barely 10 square feet, to help maintain the heading, but even then, the boat surfs so much, the propeller comes out of the water and so does much of the rudders. You loose control, the boat falls on the side, but the mast does not touch the water. You have to be harnessed all the time. Sometimes, the waves brake, hit the back or the side when you are laid on the other side, but, at sea, the hitting water is mainly foam which is good. One afternoon, I laid down on the side at least a good dozen times, but every time, dispite breaking waves, the boat would come back up again and keep on going at 5 knots! My Tibato is an athlete!
To go to Europe you need an aluminum or steel boat for the heavy seas. Also, you need it equipped so you can sleep at night under sails.