Transients are an inescapable feature of wave train interference. They can be caused by two trains of comparable frequency intersecting at angles, or by parallel trains of differing frequency. The transient can be a one-off event at a single location -- like right under your boat -- or it can 'travel' as the constructive interference pattern is reproduced thru the matrix.
But what about this:
While I get your point, you'll have to go out and get some data on how often this happens. I haven't seen it happen, but I haven't been in all that many days of large breaking waves either. Yeah the wave pushes the stern, but it isn't instant. At 30 degrees even a low AR rudder will be stalled (the keel as well), the difference in lift between them will be small, and the difference in resultant force (lift vector plus drag vector) very small. At 30 deg, 50% of drag acts as a steering force while 85% of lift does. At 45 degrees inflow, the drag and lift have an equal contribution to steering.
Is this about "small" or about "truly open" (or both)? There are surely some scaling issues here. Stability increases up by the 4th power of length. Deflections of a cantilever beam are cubic, and buckling of a column (which I presume is the limiting factor in stayed mast size and weight) is quadratic. I haven't given it a lot of deep thought, but it strikes me that the laws of relativity and similitude might give free standing rigs a weight advantage for a ~15 ft. boat that they don't have at ~65 ft. That doesn't take into account aerodynamic considerations.
Related to this topic, I am struck by who the various recent wild and wacky Americas cup editions have all kept jibs and stays.
Well, it is really not . . .if there is a possibility that some variation of un-stayed rigs are both better sailing and more likely to survive a roll-over... then it is dead smack on topic. I guess so far I'm listening but have not really heard a compelling case - admittedly I might not recognize the compelling case if it bit me in the ass :huh:
Unfortunately not nearly that simple. Euler column buckling is dependent primarily on stiffness, carbon is only a bit stiffer than aluminum (though specific stiffness is higher). Cantilever mast is dependent on flexural modulus, many times what aluminum is. There are so many differences that you have to compare real examples. It is hard to optimize a carbon compression rig because there are too many nodes and too much asymmetry, while a cantilever is pretty simple. Beyond pure weight is VCG, my 65' rig VCG is about 20' off the waterline (because both diameter and wall thickness are tapered), a marconi would be 32' +/-, that is a pretty big difference, about the same as adding a ton to the keel, or making the rig 40% lighter. Speaking of capsize resistance.
In racing, allowed sail area is king, and if the pressure was insufficient for the wing to fully power the boat, the jib was flown. I can guarantee that any winged boat would much rather have the right size wing for any condition, rather than a wing and jib, but the rules don't allow it. It's also hard to swap wings during a race when the pressure drops. Where sail area is strictly limited (C class cats for example) the last jibs were seen in the '60s (~20 years before wings). And that is, actually, one of the problematic areas for a bald headed rig, changing jibs to adjust area is not an option. Reefing gear takes care of most of that, but it's just another one of those compromises. We do carry a 1000 sq ft asym for broad reaching, but it is much less useful that the asym on a sloop because the main is so much more efficient off the wind than a sloop rig generally.
DDW, my understanding is that this is in fact not true. Across various iterations of AC wings, they have had more than enough breeze for just the wing but preferred wing plus jib. . . . I understand that this is at least in part because they can control/twist the top of the wind actually create positive righting moment while the bottom of the wing and the jib create drive. But empirically, many times with the wing, they have quite obviously had a bunch breeze and still used a jib.
Could be? Also the wing alone offers little directional control for prestart or crash recovery maneuvering. And, you do not know how conditions will change during the race, there is no opportunity at all to put one up should it become advantageous. The wing can be feathered if too much pressure, but if too little you will just slow down. If it were more efficient over a wide range of conditions, you would see them on class A and C cats where they are legal (but not used for decades). I watched some of the AC races on SF Bay, as I recall in some of them no jib was carried.
I spent some time around Royal Huisman when she was being built.
When your 'easier to sail boat' is a j-class . . . . you do rather need an entourage of 'pros and help'.
IIRC Bill King's "Galway Blazer" lost her freestanding rigs in the (original) Golden Globe to a rolling... had they been carbon in may've been a different story...
I believe there was one freestanding rig in the BOC (1982 Tony Lush's cat ketch Lady Pepperell - pitchpoled and abandoned in the Indian ocean) and one in the around alone (1998 cat schooner Project Amazon - probably a better design by Spondberg, but the two owners were always underfunded - ended up snapping its foremast and being abandoned on the hard I believe).
I missed replying to this and it's important for you.
Lady Pepperell was a modified Hunter, she did pitchpole and was abandon because the keel began to come off. The rig was still standing when abandon after the pitchpole. I did not think Project Amazon snapped a mast, rather was stored on the hard for 10 years looking for a buyer before being cut up for scrap - but could be wrong, hard to find much info on the boat's later years. Dismasting is much more of an issue with a marconi rig than a carbon free standing one. There are very, very few dismastings of Nonsuch or Freedom and it is a pretty large pool of boats. A few of the very early Nonsuch had problem because the mast builder did not understand engineering (drilled a big hole thru the aluminum mast right at the partners).
my memory, which also could well be faulty, was that with the second owner, and named Tin Can, he was trying to sail with just a jib on the foremast and it snapped and then it went on the hard because he did not have money to replace the mast.
No, actually - its all pretty much what we have already agreed.
As a general statement, we all agree that more RM and higher AVS is beneficial, all else being equal. I have stated this repeatedly. we all agree on this. However, very rarely is all else equal. You end up with design compromises and trade-offs and where the optimum point for those trade-offs will depend on the specific vessel/owners mission/purposes.
No, they are considering different things, and when you properly read/understand them, they both can/are true. In theory and in generality, we agree more RM and AVS are beneficial. BUT when faced with the power of actual 60 breaking waves, in practice the force of the waves can simply wash out the comparatively little differences between the RM/AVS's. Both of these things are true, both of these things were also findings from the post fastnet studies.
