I am not trying to argue with you, but i really dont understand
Americas Cups boats and for that matter my boat when we race are never sailing flat, especially to windward. What does sailing flat have to do with stiffness.
I undertand about over heeling a boat, so it pushes and slows down so we dont have to go into that.
I am not a brochure person or will not get into the numbers, righting ratios, even though I do uindertand them basically.
I can only go on what I see from a practicality first hand actual sailing experience. Why dont we see more Catalinas racing in the races in Annapolis, Newport or wherever. There are lots of other boats represented and there are plenty of Catalinas?
Again this is not meant to deigrate them in any way or to say I would not purchase one or it isnt good for a family of 4 ( the five included the hound and he takes as much room up as your kids////BTW kids grow up and leave....dogs dont
I can look at at Catalina as a quick cruiser....but I can not put them in same class as the Farr, Sabre, C&C, some Bennes and other racer cruisers that Paulo has mentioned from Europe like Hanse, X Yachts. They do not compete and they do not point to windward the same. They arent designed to. Seems to me if they were they would be in these races.
TO be clear, as I have said several times now, the C400 is NOT as fast as a J122 or a First as stock. No way. Corrected, I might give them a run for their money (I think that PHRF is too high, but I certainly wouldn't argue that before the race!!). Also, you mentioned why sailing flat was important? It is a piece of the puzzle. As a boat heels, the wind spills. If you have two C&C's, one has your keel and the other has a 30 foot keel, I suspect the 30 foot keel will outrun you (assuming they keep it narrow, weight at bottom, etc). Why, because they are able to maximize the same wind that you would be spilling. THis is why a sailboat does not easily turtle: as it heels, the wind forces decrease. These forces decrease until the force pushing the mast down equal the forces pulling it up. Right? That is why sailing flat (ON SOME BOATS... not all) is beneficial. That is why a stiff boat is beneficial. Using your example, the AC boats don't sail flat. Heck no. They have enormous masts and sail areas. THey are making the ideal compromise between how much forward force they want and balancing that against sailing flat. I bet if they could keep enough weight on the rail to make that boat flat, they would. The problem is that when they turn to run or beam reach, where these heeling forces are minimized, these huge masts and SA really kick in. Also, we have won races against boats that are over powered. If you have too much sail out, and your boat is heeled too much, you will actually go slower than having the correct sail are out to find your sweet spot. That sweet spot changes, depending on boats. I find many of the IOR boats like a good bit of heel. I find many of the mo modern, flat bottom boats, like to sail more flat. And since they have to finish the race with all the crew (don't laugh, you have to... funny story I can share with crew jumping off to win), its a balance.
If stiffness is defined as a boat ability to withstand the wind forces, and my boat has a higher resistance to those forces than a different boat, then doesn't that make my boat a stiffer boat? For example (extreme example): If you take two america's cup boats. They are exactly the same in every way except one has a 10sf of sail area, the other has 5000 sf of sail area, which boat would be the stiffer boat? I would say the boat with 10sf. Its ability, as set, because it has very little force opposing the RM (keel), makes it a very stiff boat. Their initial stability would likely be the same, though. Is that correct?
Note, this does not mean the 10sf boat is faster, just because it is stiffer. The 10sf AC boat is going to get smoked by the other. But the 10sf's ability to withstand the wind forces, because of a rediculously small mast and force, is much higher. It's a stiffer boat.
If I were to put the mast of that AC boat on my boat, would my boat be stiffer than the AC or less stiff? It would be a million times less stiff (assuming it didn't simply tip over)!! But with my mast, and my vastly lower sail area, can my boat, "resist the wind forces" more than an AC, and thus be a stiffer boat? If I did not have a mast at all, wouldn't my boat be a stiffer boat than an AC boat because my ability to withstand the wind foreces would be vastly higher? I simply have no force pushing it over.
THat is my issue with this discussion and what I do not understand. Paulo, I think you gave an excellent example and great explanation earlier. Thank you. I am simply saying that stiffer does not always mean faster. My boat might be stiffer than a J122 (I am not saying that it is), but it certainly is not faster. Stiffness to me seems only to be one piece of many pieces of a puzzle. I completely agree with you that if have two of the same boats, one that is stiffer than the other, the stiffer boat should be faster if everything else stays equal.