Annoyed, frustrated and disappointed.

I started repairs on my XT. Decided to remove the inspection plate and take out the interior storage box so I can remove the bits and pieces of foam and glue rattling around inside. worked great. I then decided to remove the rudder just to make moving it about easier. Well, wouldn't you know, the stainless steel (Think) rudder shaft is ceased and frozen to the aluminum tiller arm, REALLY! Honestly it doesn't surprise me and I believe I lubed the parts during installation to prevent this. I had previously complained to Daryl about using dissimilar metals for components in a salt water environment. Has anything changed that I am not aware of?
I find it RIDICULOUS that things like this are not properly designed and engineered.
Anyway, I made a dam around the shaft with plumbers putty and filled it with muriatic acid overnight and the hardware came apart with some coaxing.

Think came out with an injection-molded plastic tiller a couple years ago. However, it's only compatible with the newer Think shaft that has a threaded through hole. (vs utilizing a set screw on the older setup) . If your rudder's shaft has the threaded hole, I can send you one of the new tillers.

If the rudder shaft is the old style (threaded, with a flat), I have a stainless tiller that should be compatible.

It seems like various boat builders had a theory that anodized aluminum would work (for rudder shaft or tiller), but it clearly doesn't.

Don

If you have a standard Fenn XT both the bar and shaft should be stainless, Fenn has never made an aluminium bar. The bar has a square hole, the shaft has a tapered square machined into it. It's a bulletproof system, if installed correctly it's just about guaranteed that the rudder will not loosen while paddling. But it does require a forceful wiggle when removing the bar from the rudder.
Stick with the standard Fenn rudder, you will not find anything more reliable.

Don thanks so much for responding to my post and your offer. Nice to know there is a reliable source for much needed upgraded rudders for surfskis.
I have, apparently, the older style shaft with the flat edge. Daryl sent me along with the anodized tiller a stainless tiller, but, warned me not to use it with Dyneema/Spectra type rudder lines. Made sense because of the sharp edges. I softened the edges and used it anyway. Well it BROKE. Cracked at the set screw - see crappy photo. After reading your post I looked up and found that Daryl has created a composite tiller to address this issue - see link. I REALLY like my 10" elliptical think rudder on my XT. Performance is fantastic. Just annoyed so difficult to remove. Actually had an 11" custom cutaway rudder made that worked quite well, but, liked the better balanced elliptical more. Gave that rudder to friend with XT and he loves it. DON it doesn't look like your solutions will work for me, but, the offer is much appreciated.

Oskar, thanks for the reply. The original shark fin style rudder is a complete failure for serious downwind performance on the early XT. So far back, rudder hardly ever in water. Tip is so narrow makes situation worse. I understand the concept of sharkfin rudder that is very durable and less subject to damage with beach/surfzone use and abuse. I'm sorry but the Fenn tiller bar is anything but bullet proof! I have stripped two Fenn style square hole tillers with excessive use and wipeouts in large surf. Also had a problem with lock nut coming loose and having to come to shore on downwind, hypothermic and trying to hitch hike home at sunset. Not fun!
I plan on just making by with the set up I have til I absolutely have to replace it. I will be loading up the the shaft etc. with anti seize when I put it back together. Just feel this should have never been an issue.
Don, I would be interested in the cost and availability of the older style composite style tiller
if it is available. I would need two.
Thanks, Kirk

www.thinkkayak.com.au/2016/08/new-composite-cross-piece/

Hey Kirk, can't you get onto some beta program to test new equipment? It seems you manage to stress everything to the max Get manufacturers to send you gear and you put it through the paces and send it back broken, great QA process

Kirk: I've got new-style composite tillers, and just one old-style compatible stainless tiller - see attached pic. They're sitting in my giant box 'o tillers and need a better home, so free. Just drop me a line: This email address is being protected from spambots. You need JavaScript enabled to view it.

Kirk,
Over the last 16 years I've installed more than 1700 rudders on Fenn surfskis. If you have an "older style shaft with the flat edge" your ski is either more than 16 years old (anyone else still paddling a 16 year old ski?) or you do not have a standard Fenn rudder.
Until about 2010 the nut supplied was just a normal M6 nut and I have seen one or two come loose, but since then the rudders came with a M6 nylock nut. I have not seen or heard of one nylock nut come loose if tightened properly, and we are talking of more than 1000 skis here.
Again I recommend sticking with the standard Fenn rudder, if you have problems with that it's not because of the design.

Oskar, would you mind going back and reading my original post? I wrote this:

"Well, wouldn't you know, the stainless steel (Think) rudder shaft is ceased and frozen to the aluminum tiller arm, REALLY!"

I thought I made it clear that this is, apparently an old, Think rudder and tiller assembly.

Not a Fenn rudder assembly!

By the way I have been paddling surfskis for over THIRTY years!

Your experience is obviously different than mine. This discussion was never intended to be about Fenn skis or rudders. Keith is lucky to have a cheerleader like you!

You know it is interesting that Don Kiesling appears to have a very successful business selling improved surfski rudders that replace the original factory installed rudders. Go figure. Thanks DON!

Whoops, guess I should learn how to spell seized.

Hey, have a great day everyone!

P.S. I paddle in conditions like shown in the attached photo. How about you?

Looks like high aspect ratio elliptical rudders (like I have) are very popular.

Kirk or anyone with lots of rudder experience, I am going to get a new DK rudder for the XT and debating which style I want.

What are the pros/cons of Elliptical vs standard swept rudder? why do you like the elliptical instead of swept?

You should email DOn, after all... he knows his rudders... About elliptical, he says:

As for an elliptical shape, I’ve never seen a good argument for it, other than “it worked great on a plane from the 1930s!” Whenever somebody goes from an elliptical stock rudder to one of my trapezoidal ones, they are happy with the performance improvement.

I believe that the depth, the angle, and the balance are the main 3 variables.

OK, so let me get this straight? A guy has tried his best to help you by providing some parts for a ski which he doesn't even manufacture and you feel the need to get online and rip into him? Even after you predicted possible issues? Why even bother use the parts he sent if you are so knowledgeable as to know in advance that they will fail your lofty paddling exploits?

Stew , excuse me, I didn't know that I was ripping anybody's' rudder designs. I was only commenting on the concept that the Fenn rudder was so good that their was no room for improvement and that everyone should be satisfied with the rudder that comes installed from the manufacturer. The photo I supplied would indicate otherwise. I have not experienced one of Don's rudders. I cannot comment on that. My experience is with elliptical rudders. I am not aware of Don's design concepts and analysis. I am not aware that he does not make elliptical rudders if requested to do so. I apologize for any insult. I just know what has been successful for me. Don's rudders are very well respected as I have repeatedly mention in my posts.
When I uploaded the photo of the tiller he offered me I realized it was a very much improved version of the one that I had previously received and utilized that FAILED.
Excuse me. I was chastised by Oskar for being upset with having to remedy a problem created by the use of dissimilar metals used in the marine environment,
He also implied that I lacked the experience to be able to control a surfski with what ever rudder was originally installed. Can't help but be a little insulted,
I didn't know that the tiller Don was offering was a different design than the one I had previous experience with

The bottom line here is I thought I might be helping some one who had a similar problem a solution to fixing a problem with a seized rudder shaft to a tiller.

MCImes
"anyone with lots of rudder experience"... That would be Don. If you contact him; he will ask you about your paddling requirements, where you paddle, the conditions you paddle in and what you want a new rudder to do for you that your current rudder can't. That way he can recommend a solution specific to your requirements. The DK rudder I fitted to my XT absolutely transformed that ski.

Elliptical rudders work and they are very popular. I'm not an engineer by any means, however there is a number of things I like about Dons trapezoidal design. The differences may be subtle in use but here are my thoughts non the less. Don's rudders generally have a relatively high chord and although the rudders do taper to an extent, much of this chord is maintained all the way to the tip of the rudder. This means that in steep seas the rudder has a better chance of controlling the ski even if there is only a small amount of rudder in the water compared to the very narrow (low chord) tip of an elliptical rudder. Another design feature I like is that the leading edge is straight. An elliptical rudder has a slightly curved leading edge. This puts the steepest part of the (elliptical) leading edge at the top near the hull right where it is more likely to catch weed. The shallowest angle is right at the tip right where it might lose (effective) contact with the water in very steep waves. It seems to me that a trapezoidal design of the same (average) leading edge angle may be a little more weed resistant and also more able to maintain steering control in very rough conditions. As I said; elliptical rudders do work and the performance differences between these designs may not be huge in practice. However I feel that the trapezoidal design has a bit of an edge over the elliptical design...

Thanks Atlas and Thorsten. I emailed Don and he proposed a 9" regular or high chord design. I'll probably end up going with the 9" high chord because I value control in unruly seas over all else and your points about the surface area distribution make perfect sense. Really for an elliptical rudder to work best, it should be 180* upside down.

I was just curious why one would choose an elliptical - it seems the answer is "that's how things were done historically" which seems to be outdated now days. I assume the early designers looked at a fish (fairly logical) and made a rudder that looked like a fish's fin because, well, they do pretty well in the water.

As usual, many thanks for the feedback.

Marcus, great to see your getting new rudder. I'm sure it will work fantastic.
I think Thorstens post about the 1930's plane has merit, May well be where the design concept of an elliptical rudder comes from, (see below). I tried many different rudders when I purchased my XT 11 to 12 years ago. I had some made and even made my own. I had never heard of DK rudders at that time. Guessing he wasn't selling rudders then, don't know. After market rudders were hard to come by around here. Few options. Gave a guy a couple hundred bucks for a couple rudders down south and never heard from him again. Well, that is until I tracked him down and knocked on his door at 5:00 am. He was a bit surprised and gave me 2 or 3 unfinished rudders and my money back. Rudders worked pretty good, but thought there may be something better.
So anyway, contacted Daryl at Think kayaks he set me up with a 10" and a 9" elliptical rudders. Played around with them between my XT and my EVO. OK so I'm old guy with old toys. The 10" was the perfect fit for my XT and the 9" for my EVO. Put them on the skis and never looked back. By the way, Daryl is a great guy that stands behind his his quality products.
Started this post after wailing on the rudder post with a hammer to remove it from my ski with no luck. Became immediately obvious it would do more harm than good. Wasn't real happy about it. The acid solved the problem.
I'm guessing others may have had similar experience and now the tillers are apparently made of a composite material.
Any design rudder that makes your paddling experience more enjoyable is probably the right rudder for you.
OH, and Don is sending me a SS tiller. Thank you very much DON!

So here it is, one bad arse plane. Supermarine Spitfire.



Additional info:

en.wikipedia.org/wiki/Elliptical_wing