Possible design flaw in Tandem steering?

After the recent post entitled "The AI Is Perfect Just As It Is," I (almost) hesitate to bring this up here. The AI and TI share a very similar rudder design. For a small boat, I think it is the most mechanically complicated design commercially available. Most small boats opt for simple designs. I think PBurling and CaptRon have a very good point: why isn't the rudder design on the AI/TI simpler and more reliable? Hobie is not averse to having their rudders aft, as their very popular Hobie Cat 16 demonstrates:


If a "straight-back" design is susceptible to damage on the beach, angle it up at 45 deg or more to get it out of harms way.

My Klepper foldable boat, shown here on Shoshone Lake in Yellowstone last year, has a design which stows the rudder vertical.


The Klepper design is about 100 yrs old. Klepper boats are used by the American and French military. These boats have sailed across the Atlantic (Europe to the US), and around the southern tip of Argentina, Terra del Fuego. They have been paddled from Alaska to Argentina--some trip! And, they have been paddled in the Arctic and Antarctic. They have a VERY SIMPLE RUDDER DESIGN.

Finally, we have a variety of rudder designs on sea kayaks--all are very simple to deploy and use.


Why can't Hobie come up with a more sturdy rudder design, which allows easy deployment and a larger rudder (so it can handle the sail and conditions users find themselves in)? And, while they are at it, a better, more powerful tiller handle would be a nice change.

Keith

_________________
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

Matt:

I have to tell you that the problem is more than production variation. As I have reported, my rudder works fine in winds up to about twelve knots. I was out today for almost three hours in nearly perfect conditions. Steady wind at ten knots, which began to gust up to 15 later in the sail. I was in sheltered waters, so there was no swell and minimal chop. The TI went beautifully and the steering was equally responsive until the wind got up. Once the wind was over twelve knots I had the rudder problem. Virtually every time I tacked onto the port tack, I could hear a muffled thwock and the rudder would become very hard to handle. In the stronger gusts, the TI would round up into the wind forcing me to tack so I could reseat the rudder using your prescribed technique. Even though the TI was going beautifully on the starboard tack and wasn't in the least bit overpowered, I tried to reduce the pressure on the rudder by reefing. This helped a little, but as soon as the boat began to move in a gust, the rudder popped out again.

The TI has the potential to be a great boat and is a huge amount of fun to sail, but this rudder problem is a real pain. I'm using it in sheltered waters and could easily self-rescue if the rudder failed; but I sure wouldn't want to be out at sea where some of the owners go with an unreliable rudder system. You have too much boat for the twist and stow rudder system.

PBurling

We'll keep looking at this, but after a couple years of testing (I personally have experienced a rudder that works like a charm... even without the down line cleated ... in rough water and 15-20 knots of breeze), I'm not convinced its a design issue. Its a new product, so sometimes it takes awhile A) for us to understand how production variances are effecting design and B) to understand what it is that users are doing to exacerbate the issue.

Honestly, by looking at the posts and poll, the users that are having some issues are a smaller percentage of the posters... and posters in forums are typically the ones having issues. We will make a change when and if the production, tuning and learning to properly sail the boat can not be worked out.

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

If your design requires manufacturing tolerances that you can't consistently achieve I'd call that a design issue.

Kieth, like this one?

_________________


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

All I know is the TI vs the AI - the steering is much tighter and no where as easy to turn as the AI. I will figure out a solution to improve it one way or another. It is not the end of the world, and I still love my TI but sure would like to improve the steering a bit.

_________________

I'd rather be sailing,
Mark.

Give us some time to make that call... its REAL early on this one.

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

Yeah, Ron, your design is great and something that Hobie should consider or build on.

Keith

_________________
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

Matt, I've read every thread and post re rudder issues, and it seems to me that there is definitely more than one issue. In my case, the rudder did not function repeatedly on a dead calm day, whilst pedalling leisurely. Whilst the TI was on the trailer I did this:

1. With rudder aligned fore and aft, pulled it down, and released the down line (ie, no tension at all)
2. Noted that it sat properly in the slot
3. Noted that the latch and ramp did not engage, with about 0.5mm clearance between latch and widest point of ramp

That is, the rudder could slide in and out of the slot with absolutely no impediment. So using my new TI "even without the down line cleated" is impossible in any conditions, regardless of how calm. At least in my circumstances, I think that clearly deals with your points (A) and (B) above.

I'm considering a way to lock the rudder down - at least until Hobie works out that (1) there really are problems with some of the TI T&S rudders, and (2) works out a fix for it.

At least that way I can use my yak, even if I have to sacrifice the up/down mechanism.

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

Matt, when you say that it is only a small number of people with a problem and they are the posters here--I really question that conclusion. Your dealers are probably the ones who have a real idea about the problem and its extent. Even individual dealers have probably not sold that many TIs to be able to give you any feedback. The dealers I know do not look at the forums.

I appreciate your attention to what appears to be a real problem in the TI rudder. I don't own a TI, but I own 2 AIs, and I have always been unimpressed with the complexity of the AI rudder system. That is why I have commented here--the 2 boats/rudders are closely related.


There also seems to be "company think" resistance to changing this rudder design when it, perhaps, is not appropriate for either the AI/TI. The Twist-n-Stow rudder design might have been successful with pedal/paddle kayaks, but, I'm sure you remember that there were design problems w/ the AI T-n-S rudder the first couple years. Your engineers finally fixed a number of things on that system and "it works." Still, the AI rudder, while upgraded in size from the original issue, still is frequently overpowered by stronger winds.

It may be that the AI/TI requires a different rudder system than the simple pedal/paddle Hobie kayaks.

Keith

_________________
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

Fyi on the lock design...

The rudder is easily held down when on starboard tack as the flow of water forces it into the housing. On Port tack the pressure pushes the rudder to the left and is supposed to engage the latch to increase the resistance of the rudder coming up. This has always been the case with the Twist and Stow system.

Seems that with the apparent warpage (tolerance issue) to the rudder head, the factory has done some modifications to latches to reduce the depth... to allow them to unlock easier. This combined with other early mass production variances is adding to the list of possible issues. Hard to say which rudders have had this done. Perhaps you can find a sanded area on one that is not latching as it should.

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

Had a close look at the widest part of the ramp, and it does look as though it may have been sanded or trimmed back slightly.

Just as a thought, why not consider using a redesigned ski clamp arrangement to positively lock the rudder down, yet still be able to release on impact?

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

We tried a plunger lock on the TnS about year ago... failed. Our Hobie Catamarans have rudder cams that are spring loaded and lock rudders down, so we have the technology... but they are bulky and complex... and not without issue for the uninformed user.

The benefits of a rotating rudder that sits flush on the deck when stowed is HUGE, so I am VERY reluctant to loose that feature.

We will get past these issues I'm sure.

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

FWIW, this brief vid shows the rudder freely sliding in and out:

[youtube]http://www.youtube.com/watch?v=EU8v-sdj77s[/youtube]

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

Yes, but when sailing, there is a side load one way or the other. Either into the housing or the latch.

Btw... I've sailed in your area! 1985 Hobie 18 Worlds. 7 meter swells and blowing like stink. Wild open ocean sailing. Breakers at the river mouth on the way out. We stayed at a hotel on the point by the bowling field.

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