Possible design flaw in Tandem steering?

Yesterday I tried loosening my drum bolt some more determined to get my rudder to stay down. I gave up loosening it when the two halves were visibly coming apart and my rudder still would not stay down. Then I decided to tighten it back up a bit and found that by tightening it I could get my rudder to go all the way down and stay there when the line was cleated. It would not stay locked in the catch but it was much better.

Then I took it out sailing to see if it felt any different.

The winds were strong and gusty, in the 25 mph range. I reefed my sail to keep from getting drowned in the spray and found that my boat had quite a bit of lee helm. I was able to tack but the rudder was really hard to turn when I wanted to go through the wind. My speed was varying between 5 and 7 knots with the sail furled to the point that the large batten was totally rolled up.

I don't know why my boat is the opposite of everyone else's.

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

I'm new to this forum. Hello everyone.

I had an AI and traded up to the Tandem recently. Since our first test sail, the rudder controls were awkward, and often didn't properly engage. The following was an email I sent to my Hobie dealer on Aug 5, prior to knowing there was even a Hobie on-line forum!

"Yesterday, however, was a real adventure. The “twist and stow” tiller/rudder control system has been problematic since day one. First, the tension on the “down” pull cord needs to be constantly adjusted in order to maintain active rudder control. Second, the rudder blade often does not line up correctly with the rudder mount “notch” when lowered, and the loose fitting often creates instability. Third, the rudder pin and mount has too much “play”, which then requires far too much attention to the tiller to remain on steady course.

These minor flaws all combined to a catastrophic failure in the rudder assembly while sailing in moderate winds yesterday. The rudder would not remain in down position, even when cleated, and then the steering line broke. Unfortunately, I was at the nearly furthest point from home and also have had a knee injury which made peddling the long distance a somewhat painful experience! Fortunately, I was able to use the winds and the sail to help steer toward the closest beach to effect some temporary repairs."

I live in Lake Havasu City, and the local Hobie dealer is new, and mostly inexperienced. Any suggestions?
Is Hobie working on design changes?


GM

CoachM - Welcome aboard. The TI is great boat except some of us are experiencing steering issues like you. Search around there are a number of posts that discuss this topic.

My latest attempt at a temp fix is here: http://www.hobiecat.com/community/viewtopic.php?f=71&t=28871

I tried it out this evening and thought it worked well. I did not use the up/down lines - which improved steering tension, made it easier to steer and of course the rudder pop-up did not occur since it was locked down. I am not saying this is for everyone - or a permanent solution but for now - I will continue to go this route.

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I'd rather be sailing,
Mark.

As I posted saying I had rudder issues too, I thought I should now update my earlier comments: "whilst pedalling, in quiet conditions, I found that the rudder popped out repeatedly when not cleated down".

I am now always cleating it down, in my case as far as the aft end of the drink holder. This does not affect my steering control/effort. I had no problems during a calm 26km kayak race yesterday, pedalling only, nor the previous day while sailing in 10-15 knot winds.

Nevertheless, I'll probably still add a lock-down pin, for the wilder days &/or offshore trips.

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

What kind of lock down pin? Is it a through- bolt with nut that Mark used, or a easily removable pin with bungee that can be inserted by hand and that goes through both the stationary part of the rudder as well as the movable part. If the latter then where will it go and is there a way to insert it remotely by pulling a cord?

If it can be done remotely then you preserve the retractability feature as well as guaranteeing the rudder will stay in it's socket under windy conditions and without binding the steering.

I'm also considering a lock-down pin but not sure how to make its deployment remote.

Bob

Some kind of remotely deployed lock down pin would be cool. Locking the rudder works very well.

_________________

I'd rather be sailing,
Mark.

Here's a conceptual sketch of a remote rudder lock pin device. The steel spring bar keeps the pin up when there is no tension on pin lock line.


Bob

Interesting discussion with some great ideas being put forward.
The remote locking pin seems like it would be a great idea.
Instead of remotely locking wouldn't it be better to remotely unlock?
That way there would be no extra tension on the rudder assembly from the lock down line.
I'm thinking of a pin through rudder blade and housing, with a spring that keeps it pushed through both. To lock the rudder pull the release line to withdraw the pin, drop the blade into place and release the line. Pin slides into place. Vice versa for raising.
I would not like to see the twist-n-stow rudder replaced with a pull up rudder. I had the original pull up rudder on my (Tandem) Oasis and it was difficult keeping it damage free. Anything that sticks out over the hull is prone to damage when transporting.
The larger TI rudder more so. An 18'6' hull becomes considerably longer when the rudder is raised.

BTW- It's not necessary to drill holes in the hull to run extra rudder lines. There is room in each tube to fit another spectra line. I had two lines coming out of each up/down line on my Oasis. They worked well. The newer rudder line tubes have an O-ring that could be removed to make room.

What a disappointment!

Took my new TI out sailing this past weekend. I've had an AI since 2006 and couldn't wait for the TI's to come out. I had read about the rudder issues in the forum, but thought I would get lucky and get a boat that worked. No such luck. I have all the problems that are documented here. If you lock the rudder down hard enough to keep it down, you lose the ability to steer comfortably, or sometimes at all. If you don't lock it down hard, it just goes where it wants.

No need to go on about what it won't do. At this point it simply doesn't work. I loosened the Drum Bolt as suggested, it didn't make it much better. I tried all afternoon continually readjusting the lines trying to find a spot where the rudder would stay down and I could still control the boat. I was using less than half the sail to not make matters worse.

I'm not an engineer, but it seems that boat speed is a major issue here. At 3-4 mph the Twist N Stow system works just fine. As boat speed increases, the loads on the rudder increase and make the system less reliable. I'm sure there is a boat speed where any T and S system would be continually problematic due to the forces in play. The TI may be on the edge of that now. I know I do not want or need a rudder that has to be constantly finessed to function. The rudders on these boats should be as bulletproof as possible. Simple, functional. That is not the case now.

I was surprised when Matt seemed to approve of TxYackMan's idea of drilling a hole in the rudder and bolting it down. Either the rudder system works or it doesn't. And wouldn't bolting the rudder down completely defeat the purpose of the T and S system? I understand it is a temporary fix while we all sort this out, and I will probably use it, but it does seem like a step backward.

I am happy that there are TI owners out there with no rudder problems. I want to be one of them. I remember when the AI's first came out, there were rudder issues then too. Hobie listened, redesigned, and provided us all with a solution. I am hoping that is what will happen here. I realize we all need to give them time to sort out what the real issues are and come up with a fix. It's just so frustrating to have such a great and not be able to use it.

I'll be quiet now.

Well, let's hope that the Hobie engineers are busy mulling this issue over!

I've sketched out a snap-action locking pin mechanism which:

1. Can be easily retrofitted.
2. Uses just two snap-action devices (each device has only one moving part, plus one stainless steel spring).
3. Will release as soon as the rudder up-haul line is pulled.
4. Still allows the rudder to pop out on a hard impact.
5. Shouldn't cost the earth!

Have to get some proper tech drawings done yet, and get some engineering input re suitable forces etc.

I'll try to get prelim drawings done soon, and post here.

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

Stringy, you asked, "Instead of remotely locking wouldn't it be better to remotely unlock?"

I did a design the other way as you suggest, but then thought the default state where nothing is under tension should be with no lock pin engaged since it could damage the rudder possibly if the down line was pulled hard and it whacked against the lock pin bending or sheering it or making it difficult to retract. In fact I was trying to integrate ut with the down line so it would be imposiible to drop rudder unless the lock pin was fully retracted. But I think we can find a better solution by retracting the lock pin automatically when pulling the rudder up eg bungee it to up line such that the first force goes to retract the pin them it goes to pull up rudder while bungee stretches further.

Bob

I followed the above thread photos and replaced the first rudder bolt with
a through-bolt made of nylon with a nylon thumb screw. I made certain that
the rudder was tightly fit down before drilling a through-hole.
I normally launch my TI from my trailer so I don't have the problem of
needing to flip up my rudder with launch/recovery.
I haven't had the high winds yet to fully check on the steering but with
the through bolt...I don't need to nearly pull the spectra rudder-down line out
of the hull as I have needed to do to even have a chance in keeping the rudder
in its clip. My rudder was popping out at any hull speed over 4 knots (if I did not
cam-cleat the rudder line with a full out hard pull)!
Using a nylon through bolt as a shear bolt should save the rudder from any
accidental strike and the remaining 5 rudder bolts should hold the rudder until
I install a replacement nylon bolt if I have to.
Until Hobie can come up with a fix...this method seems to be my only option if
I want to sail in anything above a light breeze!

Max,

Your design sounds great. Look forward to seeing it.

Bob

Hobie engineers must reexamine the design of the Tandem rudder.

Below is our temporary fix.

Parts:
1 specta line
1 bungee cord



Port side:


Starboard side:


Pros:
- Holds rudder down at top sailing speeds (10 knots).
- Retracts when hitting bottom.
- Automatically redeploys down when in deeper waters.
- No additional tension on the steering lines

We have been enjoying our Tandem using this system for several months.

_________________
Marc K
2010 Hobie Tandem Island
Boynton Beach, FL

Tiddalwave,

What size bit and size nylon bolt, dia and length worked best.
Thanks,
bob