Mast rotation and it's effect questions.

Now that I am sailing solo and trapping out(lol tinkerbell and all kinds of learning situations) I now need a brief or detailed lesson on mast rotation and how it effects the boat.
My main reason for asking is, my boat has been previously repaired on the mast step, it was filled in and re-cut on port side and and it doesn't rotate as much that way. roughly if sitting on the tramp calling the center 6 o'clock(mast straight sail track is the hand) it goes to 7 o'clock port and probably 3:30 to starboard. Now, when I'm flying on one hull and the starboard hull is UP it seems the port hull doesn't want to dig in as much and I have an easier time maintaining control. Just the opposite when the starboard is down I seem to have a hard time keeping it from noseing down, I move way back, shifting my weight, it digs, my front foot with not much weight on it slips and off i go. Is the mast rotating farther putting the force to the front more? or do I need to look to something else I'm not doing right? honestly as I write this I can't be sure I have the jib as tight from one side to the other, could it be that simple?
any and all advice is much appreciated, tinkerbell kinda sucks, but i figure if I'm not flipping some I'm not testing my limits.

The mast certainly isn't rotating enough to port - and you're seeing that in the reduced power on that tack (starboard tack - wind coming over stbd side). If you sheet in the sail on that tack, you'll notice that it's not a nice, smooth airfoil - there will be a noticeable "dent" in the airfoil caused by the mast not rotating enough. The leading edge of the sail should blend in smoothly with the shape of the mast.

You need to fix that.

3:30 is about right on port tack (wind coming over the port side).

That's a funny situation. If I'm getting it right, the mast only rotates to port to about 7:00, but this helps de-power your sail so your port bow doesn't dig in when the wind is coming from starboard. I wonder if there are better ways to de-power your sail in these situations. What do the experts think? I'm a nube, but I read Rick White's "Catamaran Racing for the 90's" and here are some of his thoughts on the situation. In general, increased mast rake, more downhaul, more outhaul, and less batten tension all work in their own ways to make your sail more like the wing of a fighter jet, a swallow or a falcon in a dive. These wings get good lift, but what makes them most impressive is that they are stable at high air speeds. Sails that have less mast rake, less downhaul, less outhaul and more batten tension are more like the wings of a cargo plane or pelican. Fuller wings get great lift and can handle more weight, but they get pushed around more in higher air speeds. You want your sail to have that fast wing shape when you have higher wind speeds, lower crew weight or flatter water. If you're sailing solo, you have lower crew weight, and if you're regularly flying a hull you've got good air speed. If you do all these things, and you're still getting torqued by the wind more than you want, you can let out the main traveler some to spill off some of that excess air.

Even though your under-rotated mast may be helping you in this particular situation, it may also be causing you problems that are less apparent than not capsizing. I've never noticed how much my mast rotates in the different points of sail, but I'm guessing that 7:00 isn't THAT far from optimum when sailing upwind. I'm thinking you need a lot more mast rotation when sailing more downwind. How does your cat do on a reach with the wind coming from starboard? Is it noticeably slower than when you're doing a similar reach with the wind coming from port? And I'd also worry that the limited mast rotation on reaches and sailing downwind could increase wear on your sail due to the extra stresses from the battens and batten caps being jammed into the mast. I don't really know if that happens, but my old sail seems to develop mini-tears near the batten caps when I crank on the batten tension too much, and I'm guessing the stresses may be similar with an under-rotated mast.

Pat

Sorry for the interruption on this thread, but it seems I've got a related issue. I've noticed that my mast rotates stop to stop - actually over rotating on a close reach. Shouldn't the luff track be more or less in line with the position of the traveler? I'm wondering if I have very old sails or is it something I'm doing wrong.

The mast should freely rotate, stop to stop. Using the clock analogy above, with 12 forward and 6 aft, the mast should go from about 8 o'clock on the left to 4 o'clock on the right - maybe a bit more if the stops are worn.

My mast rotates as described, but even on a close reach, the mast is fully rotated to the position you mention. Is this normal?

Yes. It will always be rotated to the stop on one side or the other.

Pat, thanks for the reply, I guess over this off season I'm about to be having I better read Rick White's "Catamaran Racing for the 90's" and get more knowledge about tuning. By the info you shared I'm doing some things all wrong, I had just tightened my battens before that weekend and in the beginning I took rake out of my mast to have room to go under and be able to see a little better because I dont have windows and really couldn't see much the way it was when i bought it, it was also leaning way to port badly so in making it straight the reduced rake was a side effect but i liked it. Now that Ive learned to sail perhaps the rake would be a good thing.
The rotation to port is the same no matter what as the step has been filled in with aluminum and the stop is just plain cut wrong.
New mast base and step I think I will buy just to make it right the easy way.

When I take down the mast I'll measure all my rigging and most likely buy new also since the boat is older, that will let me set it up better in spring on land with the experience I've gained and will continue to.