Yes, the definition of "mark-room" is a little different than the old "room". That's why I included the weasel-words in my previous post. For those not thoroughly conversant with last year's rule 18, I usually say the game hasn't changed. If you did have a firm understanding, some of the details are a little different. Here's my take on mark-room (which I got from Dave Perry at the February SAYRA Judge's Seminar).

Last year, "room" always meant time and space while acting promptly in a seamanlike way. Now, "mark-room" has two parts:
1) "room" to sail to the mark, and
2) when at the mark, "room" to sail your proper course.

The first part is a little less room than the old rules allowed. They were generally read to allow a "seamanlike rounding", where the apex of your turn was at the mark. That meant you could come into the a little wider (though still not as wide as a tactical rounding). Now you just get room straight to the mark.

The second part, however, gives you a little more room than previously. You get room to sail your proper course when at the mark, which could include more space than needed for a seamanlike rounding. For example, if the course or the wind conditions make your proper course to tack around the mark, then "mark-room" includes room to tack.

From a catamaran racing point of view, I think the differences are probably smaller. We generally approach a mark (particularly leeward marks) much hotter than most monohulls. Our normal entry angle to a leeward mark would usually permit a seamanlike rounding anyway. While you could drive a windward boat directly above a leeward mark, turn down, and make it sail dead downwind directly to the mark, that would be slow.

Likewise, we rarely tack on the leeward mark. It's almost always faster to build up some speed after rounding and then tack. So, cats typically wouldn't use that bit of extra room anyway. Ours is more a game of speed and less of maneuvering than it is for monohulls.

I think these distinctions may be important for Alter Cup or Olympic caliber sailors, but not so much for the rest of us. At my level of racing, I'm still giving boats pretty much the same amount of room as I did last year.

Does that make sense? What sort of scenerios make you uneasy at gate roundings?

Regards,
Eric