I have been pondering these change of events more; and more things have begun to bother me. I don’t look at the Footy aspect of this class as a “gimmick”, but a challenge. Hey! let’s face it, we all know how bigger, longer boats perform. But the challenge was to make a boat perform within the limitations of foot. The foot I was born with is 12" long, so unless I become the class clown I have problem growing a bigger one.
Bob
We’re miscommunicating I think … what I mean is put the stern in the bottom corner (rudder would have to move forward and wouldn’t stick out either slot) … you could get more depth to the rudder by also pivoting the entire boat along its longitudinal axis …
In theory the hull with a catboat rig would have a greater tendency to submarine than then the same sloop rigged hull … the catboats I know are all big beamy creatures … likewise, I’m guessing that the footy designs to date are generally beamy and forgiving enough that they can handle the rig … not having experimented myself at this size, I can’t of-course say for certain … and like always, I’m eager to learn … given your practical on-the-water experience, what is your opinion as to why the gaff rigged catboat works … ?
much regard, Trevor Paetkau
OK Trevor, I understand what you mean. My catboat sails most likely because it is slow:) 
. Moving the rudder forward, you would lose control? Might find tacking to be an effort, especially in a blow. More knowledgable people need to comment
Bob
Move the rudder to the bow - forward of the fin.
a geek rudder huh? that would take some work, and i am not sure whether it would be an advantage with out a rudder aft as well, and if i remember correctly after much debate it was decided that multipule rudders were offlimits… right? as for the wave length angus, you are probably right… i still maintain that the chop was 4" tall… 
quote… From Angus…
420 - PLEASE.
Try drawing some waves 5-6" apart and 4" high. I’m sure it was a nasty short schop, but that short and steep it’s breaking - and how!..quote.
Well after that little interlude back to the wavelength 420…
Were you perhaps in a part of the lagoon suffering from interference waves? That could explain the short steep chop.
I did some practical experiments involving pitching frequency and amplitude of a Kittiwake in still water. Numbers were supplied to Angus to crunch but I have seen no results of your masticulations Angus?
At decent speed the Kittiwake CR2 prototype cuts the chop pretty well and does a reasonable impression of a platforming hull… so it is achievable at this size. If typical smaller lake wavelets in a mid range wind are 4" to 6" I wonder how that sits in relation to the hull pitching frequency.
Graham
USA10
photo… sometimes we get a bit of chop on Lake Michigan too…
Sorry Graham, thought I’d told you the rather disapppointiing (?) results. At a daft of 11 inches the natural harmomic pitch freqquency of a Kiitiwake will not result in fin stall at any likely operating leeway angle.
ok Angus… sounds good to me. Where did 11" draft come from by the way?
Graham
Velocities corrected for notional extreme value (1" freeboard).
ooooo I love it whan you talk dirty…
G
While 4" tall waves with a wavelength of 5" to 6" stretch my beliefs a tad, it’s only a tad. The description also uses the word “chop.”
The lake I sail in most has concrete sidewalls that reflect waves nicely. The walls curve gently. Thus the small waves generated by typical sailing winds end up producing very choppy waters. In fact, right now I cannot remember ever seeing waves in that lake, only chop. The apparently random peaks and valleys tend to be maybe a foot apart and might be 4" from crest to trough - not too far from 420sailor’s description, in other words. (Yeah, I know that 5" to 6" is only half of one foot, and on this scale, that factor of two difference is highly significant in an engineering sense. We aren’t necessarily talking about an engineering sense, but about a visual impression on a typical human being. Now, 420sailor, all you have to do is to assert that you are a typical human being rather than a wave scientist, and you’re home free.)
Mike Biggs
Mike Biggs
And I thought you were a mech eng! Waves like that can exist (interference patterns, reflection, tide races, current over discontinuities in the bottom). Th fact remains that if they are as short and steep is that they are more or less unstable - hence ‘breaking’.
Seriously, what I was doing was to try to suggest very gently that a designer should try to measure or at least ry to arrive a asn accurate assessment of the conditions in which he is assessing his design. B…s… for the customers is fine. B…s… for home consumption is dangerous.
Oh, I am a mechanical engineer myself, but realize not everyone else is. While I agree with the gentle point you were making that a designer should try to be accurate in assessing the conditions he’s attempting to sail in, I also recognize that nearly everyone overestimates the waves he’s sailing in. This is most recognizable among big boat sailors, whose “advantage” of being out there among the waves, with the boat tilting downhill into the troughs and then uphill towards the crests, leads them to see the waves as being of higher amplitude than someone on a stationary platform would see them. Even those on stationary platforms tend to overestimate, probably because of the long slopes up and down, unless they are clued in to watch out for that problem.
While I do not doubt that waves would be unstable if they were of 4" amplitude on a 5" to 6" wavelength, I’m not nearly so sure about chop. Much of the chop I’ve seen in our rc sailing lake appears more pyramidal than wave-like. I won’t claim to have seen that amplitude spaced that closely together, but there sure isn’t any tendency to break, either. Of course the chop is caused by multiple reflections and interferences (in this case, “patterns” is probably too strong a word); the result is highly chaotic. And I’ve seen such chop play heck with my Footy, putting it into a hobby-horsing mode that goes nowhere - which indicates there is at least one strong frequency present among the apparent randomness, but there still aren’t any apparent waves.
Mike Biggs
Interesting and probably correct. As one of those big boat sailors I am inclined to think on a much larger scale. The kind of chaotic chop or popple that you get, for example where the wind is blowing into the corner of a dock and waves are being focussed along two sides has never in the past been on a large enough scale to be interesting.
I agree very much about the difficulty in assessing the size of waves from a yacht. I think this is partly because with a ‘pure’ wave, local ‘down’ is always normal to the face of the wave. (Froude’s’ Experiment). In other words, the peak of the next wave - which is actually at the same height as you - appears to be much higher. The power of such accelerational illusions is apparent even if you have never gone sailing full size. When a passenger jet starts to accelerate down the runway, the nose appears to go up almost immediately - but when you look out of the window it is still firmly planted with all three legs on the ground.
big boat sailors? what do you sail?
Now nearly bedbound by heart disease and arthritis but traditioally between IOR mini ton and one ton. Six Fastnets, 7 ton cups (quarter, half and one). Evene casual (i.e. fill in because regular guy was sick) US Admiral’s Cup Team in 1973 - Saly Goose. Beautiful boat to windward in a breeze.
When a passenger jet starts to accelerate down the runway, the nose appears to go up almost immediately - but when you look out of the window it is still firmly planted with all three legs on the ground.
Actually it does rise, and depending on the type it can be a considerable amount. When we would position the L-1011 on a short hop, light on fuel, the wing engines would have to be advanced slowly because of the amount of nose up pitch. There can be more than 24" of travel in a nose strut, and even though the nosegear remains in contact with the runway, there is still a lot of movement in the fuselage. Also doing max performance takeoff in a fighter, holding the brakes and advancing the throttles to 100% military, when you released the brakes you definitely got the nose up pitch.
Thank you very much Larry. It shows the powr of witchcraft. I was told that one many years ago by someone who claimed to know - and it looked sensible in principle. When you actually do the sums, the acceleration of a 737 isn’t anything like enough to produce what I guess to be the perceived effect.
MOTTO: believe nothing. check anything you can for numerical plausability - which I think is where we came in.