Well, as the boat heels over to 90 degrees... as long as the center of gravity never reaches a point directly over the toe rail, it will always right itself so let's use the toe rail as a pivot point and lay this theoretical boat on it's side. On one side of this pivot point we would have the mast and the upper deck and on the other side we would have the rest of the boat.
Let's assume that about 250 lbs is on the mast side and the other 2,000 is on the keel side (very conservative as I'm sure the upper deck and mast weigh a lot more than 200 lbs). Let's also assume that the "arm" of the keel side is half-way from the pivot point out to the end of the keel (this is also conservative as I'm sure it is a lot closer to the pivot point). With an approximate freeboard of 2', this means that a draft of 5' plus 2' freeboard gives us 7' from pivot point to keel tip. Half-way would be 3.5'. With a 3.5' arm and a weight of 2,000 lbs, we have a moment of 7,000.
For the mast side, we will assume the center of gravity for this portion is half-way also. The mast height is 25' plus about 2' for the toe rail to the step height... total 27'. With this portion weighing 200 lbs, the moment would be 5,400. So far, so good.
Now, to perfectly balance the boat on this pivot point (toe rail) we subtract the 5,400 from the 7,000 to get a moment of 1,600. Finally, we divide this moment by the arm (length from the pivot point) to get the weight that would balance the boat at that point. In this case, we are talking the top of the mast. So...
1,600 / 27' = 59 lbs
Any more than 59 lbs of force at the top of the mast, and the boat is tipping over.
Also note that when a sailboat is sailing, it isn't just the weight of the keel that keeps it upright. There are aerodynamic forces coming into play with both the sails, keel and hull. For wind pressure on sails:
Wind Pressure per Square Foot = (0.00256) x (Wind Speed in mph)^2
So with the Catalina 22, the total sail area is about 205sqft. This calculates to 328 lbs of total force for both sails in 25mph winds (kinda getting up there for this boat). With the sail plan, the center of pressure is about 1/3 of the way up from the bottom of the sail and with a 25' tall mast, this places it at about 8.33'. The center of pressure is the average point at which the total force of the wind on the sails acts. Add 4' to that to get the height above the waterline. This is 12.33'. With a force of 328 lbs of total force at a point 12.33' up from the waterline, the moment would be about 4,050... not enough to tip the boat all the way over. Remember that it needs to exceed a moment of 7,000 to completely tip it past the toe rail and as it tips, the vertical component of the sail area exposed to the oncoming wind is lessened.
Anyway, like I said, it is actually much more complicated than that but suffice it to say, this boat is just too light for it to make any sense climbing the mast when it's in the water. But it was fun doing the calculations.
