Possible design flaw in Tandem steering?

I tend to agree with Keith, thinking the Twist N Stow was bigger on the "wow" factor than a functional improvement, at least on the water. Additionally, it appears the system has always been a challenge for Hobie. When the larger sailing rudder came out, the system seemed to be overworked and changes were made internally as well as special methods to hoist the heavier rudder.

Many remember the breakaway threaded screw that attempted to keep the rudder in place after the AI's first came out. Then there was the internal detent inside the twisting mechanism. Finally, the up/down lines seemed to tame the rudder's wayward tendencies.

The concept is not without its merits, however. Besides the "coolness" factor of flipping your rudder, the convenience is great. Those who had the earlier (pre T&S) Hobie rudders can appreciate how much easier loading, transport and storage are with the T&S.

In spite of the additional maintenance the system requires, It's a pleasure to use when it works well. I was fortunate enough to have had no issues with it with a couple of different TIs. The system evidently worked well for both of the TI challengers in the grueling Water Tribe races earlier this year under extreme conditions.

Hobie obviously has a commitment to the system and has been able to overcome it's inherent disadvantages so far. The TI problems seem to have materialized in a post-production environment. IMO, it's premature to ask Hobie to abandon the concept without giving them a decent opportunity to study the issue and develop and test a reliable solution.

There have been some excellent suggestions on temporary fixes as well as possible avenues to investigate. Not only has this has got to be very helpful feedback to Hobie, but also for the rest of us on how to recognize and address any problems that we may have.

Thanks to all those who have participated -- some great stuff here!

Yeh, we've got one of those days today, blowing like hell, small vessel warnings. And I've only had two windless outings in the TI! Still, imagine sailing through the bar at the river mouth in those conditions, and losing rudder control? Would turn my Sharkskins brown!

So Matt, are you saying then that the rudder should slide in and out freely, without sorta 'snapping' into place? Coz it sure wasn't staying put whilst pedalling, without the down line cleated.

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Cheers, Max ● TI: the "Yella Terra" ● Website: www.MadYakker.com ● YouTube: madyakkermax

Totally agree, it's a clever design "in principle", and has apparently worked well on the AI... hard to know why the issues on the TI. However, there are many situations where it sure won't be amusing to lose rudder control suddenly, so I'll look into the 'Locking" option.

Actually, I discussed this with Josh "Yakass" Holmes, who came up with a possibly good idea: remove one bolt on the rudder - top row, closest to the housing - drill a hole in the housing plate, and use a plastic brace pin (or something that can snap easily) to lock the rudder down. Josh is checking with Hobie to make sure this won't void my warranty first though.

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Cheers, Max ● TI: the "Yella Terra" ● Website: www.MadYakker.com ● YouTube: madyakkermax

I think we should look at two TI's side by side out of the water. One that sails like Matts with no problems in high wind conditions even without the 2:1 down line tensioned. The other one would have the problems described.
I'm quite certain we could eliminate the issue of manufacturing variances versus design flaw.

If I were to guess what they would find it would be the following:
1. Manufacturing tolerance issues relate to rudder staying locked down or not staying down without 2:1 down tension.
2. Those that have the "not staying down" problem must rely on the 2:1 down line tension and 100% of them have the hard to turn right problem due to the left pull of the 2:1 down line since that is a design issue.
3. Solving problem 1 above makes 2. irrelevant.
4. But if 1. as a manufacturing tolerance issue cannot be solved then the design issue of left torque needs to be addressed.

For those of us who have a TI that doesn't stay down without considerable 2:1 down line tension with the 100% probability of difficult right hand turn, we need a solution.

Tensioning the steering lines will not compensate the left torque 2:1 line problem since any tension on one steering line is exactly matched by an equal and opposite tension on the other line since they are a coupled system tied together. Therefore no amount of tension will produce any net force either left or right to compensate for the 2:1 down line left torque.

What is needed is a counter right torque produced by the 2:1 down line that is also a closed system like the steering mechanism so whatever down force is used is applied equally and opposite to the right side. See drawings and photo simulations below.

When I looked at the photo simulations it became apparent that this design will not work since the torque changes as the rudder rotates. Look at last photo and you can see there is no torque on one side and maximum torque on the other. I'll still leave the design up since it shows why this design option won't work. Back to the drawing board.

Bob

Capn Ron and I have discussed this technique and are going to do this on my TI as an experiment. If it works, we are going to come up with a external rudder lock configuration. He did this on his AI and works great.

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I'd rather be sailing,
Mark.

There are those who are obsessed w/ the cool factor--the Twist-n-Stow rudder and the Twist-n-Seal hatch covers are examples. As a long-distance AI sailor, I want reliability. The AI/TI boat's huge appeal is their simplicity. The T-n-S rudder flies in the face of that simplicity. While well-intentioned and very creative, some of the "new designs" of the T-n-S rudder are going in the wrong direction. Simplicity, gentlemen.

CaptRon's variation (see his posts) may be the way to go.

CaptMax--the T-n-S rudder DID NOT work well on the AI for the first 2 to 2.5 yrs of its existance.

Keith

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2015 AI 2, 2014 Tandem

"Any intelligent fool can make things bigger and more complex ... It takes a touch of genius and a lot of courage to move in the opposite direction." A. Einstein

"Less is more" Anon

I looked at Max's video and my problem is similar.

The diference is that with my rudder down line pulled as tight as hard as I can (I'm 6'3" and weight 225 lbs.) and locked in the jam cleat my rudder still pops up and inch or two so there is no chance of getting it to engage the lock to engage while sailing.

Matt said something about loosening the rudder mechanism and possibly drilling a hole out to allow proper adjustment. My dealer and I have already loosened the mechanism and he doesn't want me to loosen it any further but I looked at the tech bulletins posted and it doesn't say anythng about drilling a hole out.

My dealer has 3 new TI's coming in this week and has asked me to bring my boat in when he can sit mine side by side with one that works. Then he might be able to figure out the problem with mine. If he comes up with soemthing I'll post it on this Forum.

Jerry

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Jerry D.
St. Johns, Florida
2010 TI
2008 AI

FWIW, I suspect the aka brace shear pin may be a bit strong... I had also thought to use a thickish cable tie, feed it through and secure using a second tie on the end of the first, but that's rather fiddly.

Maybe just file down the shear pin to make it thinner (and therefore weaker)? And drill a hole in the threaded end and secure with an R-clip?

Look forward to hearing how it works for you, as I must have mine ready for the Port Macquarie 3 Rivers Race this Sunday.

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Cheers, Max ● TI: the "Yella Terra" ● Website: www.MadYakker.com ● YouTube: madyakkermax

That is the idea, but simply pedaling... there is no side load to hold it in the hook.

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Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

Maybe we can persuade Matt to test a random sample or two from the production line in the kind of conditions that have caused problems for us.

Not to make lite of steering issues, but this one struck me...

[youtube]http://www.youtube.com/watch?v=I2DZmwng7tM&feature=player_embedded[/youtube]

Mark rounding accident knocked both rudders from the transom of this 40 footer.

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Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

Since we have a bunch of AIs and a number of Tandems here in use... in a wide variety of conditions... we have done and do this already.

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Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

"Damn the torpedoes, Full speed ahead!"
You think they might have eased those sheets before they jumped off

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CaptRon
"Anything's gonna happen,
it's gonna happen out there"

Too right Ron! Had I done nothing for as long as they did, when I jumped from a plane and my main chute didn't open, I would have been a squishy mess.

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Cheers, Max ● TI: the "Yella Terra" ● Website: www.MadYakker.com ● YouTube: madyakkermax

As a TI owner, I have become an expert on alternate emergency steering methods.

Why didn't they just shove the paddle in the water to tack?

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Marc K
2010 Hobie Tandem Island
Boynton Beach, FL