Bastonjock,leon,whats the heaviest stuff that you have been out on? im thinking of doing a 130nm crossing next year,im going to beef up the keel first and the rudders.
You may consider DaveB's warning since he can speak of the
and I'm certainly not qualified in that departmnet. My 
Does have the ballasted keel which is also much, much stronger than stock. I now use stock rudders, which are much stronger than IDA rudders. I also have 3 reefs in the mainsail, though that's been around for a short time. That said, I've had the out in approximately 40 knots. I recorded a gust in the mid-high 40s on a handheld gauge. This was in shelter waters i.e. San Francisco Bay, so you would get the heavy big, frequent chop but not much in terms of swells (excpet near the Golden Gate) The boat is difficult to sail in these conditions. It's a workout, probably not for newbies, and not for the timid, but it can be done, and I never felt like I was in serious danger. In the ocean, I've had her out in massive swells, mountainous swells (but I really don't know how to judge wave height i.e assign a number in feet, etc.) On a fairly recent trip, waves were breaking several miles offshore. I was heading out under power (planned to go 4-5 miles offshore) before hoisting sails. I managed to maneuver around most of them but ended up taking a couple breakers. Boat handled it without a problme. One was a bit scary as a huge wave was curling above me. Had to be higher than my spreaders, getting close to breaking. Hit the throttle all the way and somehow climbed to the top of it, slicing the crest just as it broke, turning around to see this massive white monster 
Took some small breakers on the beam while under sail... no problem (but sure wouldn't look for them.) Probably the biggest winds I've seen in open ocean on the mac were about 25 knots. I'm a bit concnerned how she would do in 35 with the seas that would ensue. I chartered 3 times so far. Jenneau 32, Bene35, Bene40. Every trip, there was at least one day of heavy stuff. 40 knots in Greece on the 32 footer, 25 knots in the Bahamas on the 40 footer, and 45+ in Sea of Cortez on the 35 footer. That one was the harriest becasue of the following seas. First and only time I had to bite down hard and keep myself from panicking. We were also out of booze 
The biggest thing with seas in not so much the wave height but how close together the waves are, and whether the waves are breakers. Even huge waves are not a problem if their height is less than the seconds apart (i.e. seas 12 feet every 14 seconds) From what I read, most storms don't produce breaking waves. These are obviously the most dangerous and can capsize a boat if hit on the beam. An 8-10 foot breaking wave on the beam could capsize a Mac. Take it on the bow, however, and you'll probably be OK. Nice thing about the skinny Macs is that skinny boats are more difficult to capsize than fatter ones. The Mac's capsize ration is 1.9. Anything below 2.0 is considered very good, and ranks favorably, even vs. much larger keel boats. Nice web site here: http://image-ination.com/sailcalc.html
Disclaimer:
Don't try this at home. I'm not condoning anyone try anything dangerous. I'm not an expert. I'm not giving any sort of advice. Just sharing personal experience. Always ask your mother first. Must be 18 to qualify. Lawyers stay away.
LD
TRIPPLE REEFED!
the keel boaters tell me that the waves are harder to handle close in to shore so im thinking of trying a bit further out.
