Bob
Sorry to hear about the wing tip not working out.
I broke (sorry roadrunner) the first one transporting the yak. Hadn't gotten around to making another since I got the new balanced sailing rudder..
I finally wrung out the AI yesterday.
Went to South Point. Winds around 18+ knts, gusts to 22 or more? (weather ananometer report). Wind waves 6-8 feet.
Not nice for fishing, and hell beating to windward, but I was interested in the safety aspects of getting caught out in similar, or worse conditions which has happened to me a couple of times..
I'll post the trip later with some photos.
My initial impression is that these conditions overwhelm the current rudder.
Tacking was difficult even with pedals. Almost had to wait for the right wave to turn into tack.
I note Phil's foils [
http://philsfoils.com/designTips.html#rudderplanform ]state:
thick foils have higher drag, but more lift, and they won't stall until higher angles of attack. Thick foils are also mechanically stronger, all else being equal.
Considerations:
if you steer aggressively in waves, then consider going for a thicker section.
The NACA0012 section (12% as thick as its chord) is a good compromise.
Not sure if a thicker section would have helped. Maybe a longer rudder? If so consider the flip side is down swell. Is a higher aspect ratio needed? Again from Phil's site:
Aspect ratio: if you've ever had the experience of going really fast downwind in your sailboat and had the rudder feeling just 'go away' (it feels like there's nothing back there) then you're a good candidate for a higher-aspect ratio rudder blade. A high aspect rudder has a more sure feel to it at higher speeds, but with the trade off of losing steerage earlier in light air. High aspect ratio rudders also have to be built stronger - the longer blade has more leverage and is more likely to break if it loads up (if a rudder is going to break, it usually breaks where it enters the headstock).
Phil lists Hobie's Aerodynamic Forces as one of his references. I'm sure the Hobie engineers know all of the above.
What they probably don't know is the usage the AI is being put too. The ocean conditions. So they design for what they experience? Southern Cal?
While the rudder can't be changed in a few seconds, it doesn't take more than a few minutes. Maybe an option would be several rudders. I would not mind paying to have an extra one for my conditions.
To be able to quickly change for conditions would IMHO be a big plus.
Several yak companies can do fast rudder swaps BTW. Mirage takes a minute.
http://www.mirageseakayaks.com.au/featu ... tures.html
So for the '09 yak,and RETRO FITS as appropriate, several rudders, STRONGER RUDDER MECHANISM, faster swap out, and hatches big enough to stash your spare rudder (and drive).
PS Rio
I've crossed the channel in an OC-6. Also operated there many years while in the Navy.
I think your big problem may be spells of not be enough wind. Try and pick something where its blowing 10-12 knots. Would the tail end of a Santa Ana blowing offshore be OK?
http://www.weather.gov/forecasts/graphi ... a.php#tabs