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Hobie Mirage Tandem Island Problems - Rudder, Wheels, Aka
http://www.hobie.com/forums/viewtopic.php?f=75&t=33895		 Page 1 of 2
Author:  ROBO [ Mon Feb 07, 2011 4:07 am ]
Post subject:  Hobie Mirage Tandem Island Problems - Rudder, Wheels, Aka
Hi All
Helen and Stephen Robertson from Northern New South Wales, Australia.
We purchased our fantastic Hobie last October, and have used it approx 10 times to date. Fantastic boat, but problems are appearing that we are very concerned about.

1. Rudder - sailed four times and rudder split on the horizontal approx 3 inches below the top of the rudder. We were coming about in 6 knots of wind and we totally lost rudder control. Furled the sails, and no steering. The rudder had totally snapped in two for no reason. The rudder was replaced with the previous model, to allow us to continue sailing.
We have been experiencing "rounding up" of the hobie in strong winds, and loss of rudder control. Yesterday, we were sailing in the Clarence River, wind speed approx 20 knots. We were running upwind, and experienced severe rounding up. On checking the rudder by Steve who was out fully extended on the tramps, he discovered that the rudder was angled at approx 15 degrees off the centre align leaning towards the port side. The rudder was Backlifting approx 25-30 degrees, which resulted in the rudder lifting upwards. This resulted in a total rounding up of the Hobie into the wind, and loss of control. This is not a favourable position to be in. We are fully aware of furling the sail, but in these conditions we did not feel that this was an option, the hobie should fully handle these conditions. This is a severe rudder problem that needs addressing.
2. Wheels - so far both tyres have fully blown out - appear to not cater for the weight of the Hobie. Prior to launching yesterday, Steve noticed that as soon as he put the wheels in the Scuppers, the hull took on a downward banana shape which is difiguring the shape of the hull. A friend of ours has just experienced fracturing of the hull in front of the scupper holes. He has just received a replacement hull. What we have noticed, is when the wheels are in the Scuppers, and you pull the hobie forward, the wheel uprights are applying pressure to the front ledge of the Scupper hole. We have been advised to continue using the wheels but we are very concerned that our hull may also crack. It appears that a sleeve is needed to act as a buffer against the metal trolley wheel uprights.
3. Akka Rivets are starting to become loose. The front Akka Rivets are loosening and rising from their holes, which we feel may cause total separation.

We do understand that this information is used by Hobie to make improvements and adjustments and we trust that answers can be provided and we can all work together to make it better for us all.

Helen and Stephen Robertson
Maclean, New South Wales
Australia
Author:  Chekika [ Mon Feb 07, 2011 9:23 am ]
Post subject:  Re: Hobie Mirage Tandem Island Problems - Rudder, Wheels, Ak
There is lengthy discussion of the wheels and damage to the scupper holes: http://www.hobiecat.com/forums/viewtopic.php?f=71&t=33359&start=0

Keith
Author:  mmiller [ Mon Feb 07, 2011 10:18 am ]
Post subject:  Re: Hobie Mirage Tandem Island Problems - Rudder, Wheels, Ak
Be sure the cart is resting on the crossbar pad and the post clamps rest against the bottom of the scuppers to get a three-point contact with the hull. We have been hearing that some users in Australia have positioned the clamps too high on the posts which adds a LOT of leverage force against the scuppers when pulling the load.

The cart wheels should be Heavy Duty or at minimum the Trax 2 variety. Older trax tires do not have the capacity needed.

Contact your Hobie dealer or Hobie Australia with any additional concerns.
Author:  chrisj [ Mon Feb 07, 2011 12:55 pm ]
Post subject:  Re: Hobie Mirage Tandem Island Problems - Rudder, Wheels, Ak
mmiller wrote:
Be sure the cart is resting on the crossbar pad and the post clamps rest against the bottom of the scuppers to get a three-point contact with the hull.
That's interesting Matt. I thought the purpose of the clamps was to lift the hull slightly clear of the crossbar, so as to avoid the horizontal groove that forms between the scupper holes.
Author:  mmiller [ Mon Feb 07, 2011 3:36 pm ]
Post subject:  Re: Hobie Mirage Tandem Island Problems - Rudder, Wheels, Ak
chrisj wrote:
That's interesting Matt. I thought the purpose of the clamps was to lift the hull slightly clear of the crossbar, so as to avoid the horizontal groove that forms between the scupper holes.


The clamps take some of the load off the crossbar and distributes it to the scuppers. Some guys were placing the clamps high up on the posts to get the boat higher off the ground... that causes more stress on the scuppers than intended.

Simple adjustment of the cart clamps is to flip your hull. Slide the cart into the scuppers to where the crossbar pad touches the hull (simple gravity). Then adjust the clamps to get them seated against the scuppers. That is the three points of contact we want.

http://www.hobiecat.com/forums/viewtopic.php?f=21&t=33397
Author:  ainut [ Mon Feb 07, 2011 9:36 pm ]
Post subject:  Re: Hobie Mirage Tandem Island Problems - Rudder, Wheels, Ak
As far as the carts are concerned I only use them to get to the water,when parking up for a while, I custom made a cradle {with all the curves of the hull to stop hull distortion} I have also owned an AI, distortion of the under hull wasn't as bad as in the TI.{Weight factor}
Having the cradle makes a huge difference as far as keeping it's shape, I use the cradle to car top as well, I have just come back from Holidays the temperatures averaged 36- 38 deg celcius, more than two thirds of the hull is supported, but in the heat the bow end would drop half to three quarters of an inch, the way I found this out was in the morning the bow line which was tethered to the nudge bar on the front of my utility,but by lunch time the bow had sagged downwards.
it hasn't seemed to make any difference, and probably reverts back to it's original
hull shape.
my rudder has also snapped, if there are two of you in the boat it's generally no problem as the guy in the back becomes the oarsman.
Author:  Julian Patrick [ Wed Feb 09, 2011 10:13 am ]
Post subject:  Re: Hobie Mirage Tandem Island Problems - Rudder, Wheels, Ak
Two snapped rudders... wow
Author:  mmiller [ Wed Feb 09, 2011 1:26 pm ]
Post subject:  Re: Hobie Mirage Tandem Island Problems - Rudder, Wheels, Ak
Julian Patrick wrote:
Two snapped rudders... wow


The rudder will be much stronger on the new rudder system.

The molds are ready. Test parts being run soon. Then some extensive testing. Ready for distribution to all owners in a few months if all goes well.
Author:  mickeymouse [ Thu Mar 17, 2011 3:34 pm ]
Post subject:  Re: Hobie Mirage Tandem Island Problems - Rudder, Wheels, Ak
Quote:
3. Akka Rivets are starting to become loose. The front Akka Rivets are loosening and rising from their holes, which we feel may cause total separation.

Robbo - has this problem been fixed?
There appears to be a serious issue of galvanic corrosion occurring
due to using aluminum & stainless steel together.
I believe one of the TI participants in the recent Everglades Challenge has reported the same problem.
Would be interested to hear anything you have to say about this.

Perhaps Matt may chirp in :roll:
Author:  Fly4v [ Thu Mar 17, 2011 10:22 pm ]
Post subject:  Re: Hobie Mirage Tandem Island Problems - Rudder, Wheels, Ak
The galvanic corrosion is not limited to the TI, The 2011 AI suffers the same problem at the rivet holes.
Author:  mickeymouse [ Thu Mar 17, 2011 10:44 pm ]
Post subject:  Re: Hobie Mirage Tandem Island Problems - Rudder, Wheels, Ak
Fly4v wrote:
The galvanic corrosion is not limited to the TI, The 2011 AI suffers the same problem at the rivet holes.

A mate of mine is in the processor of submitting a warranty claim for noticeable corrosion (under the paint) around the rivet points of the akas. This has occurred within 3 months of careful use :o
Author:  Pirate [ Fri Mar 18, 2011 3:52 am ]
Post subject:  Re: Hobie Mirage Tandem Island Problems - Rudder, Wheels, Ak
It must be noted that boat has painted akas, not the new anodised finish like the latest. Don't really know if that makes any difference to this problem but worth noting here....Pirate
Author:  Gringo [ Fri Mar 18, 2011 6:31 am ]
Post subject:  Re: Hobie Mirage Tandem Island Problems - Rudder, Wheels, Ak
I've been living in a very corrosive tropical environment now for several years, and dealing with this dissimilar metal issue daily. From what I have seen, if you put aluminum in physical contact with any other metal, even including a different alloy or grade of aluminum, in a high salt, oxygen, and moisture environment, one of the two metals is going to suffer. Almost always the softer aluminum. Aluminum turns into aluminum oxide, very quickly. (By the way, did you know that aluminum oxide does not conduct electricity? Don't ask me how I found this out, and am still here to tell you about it.)

And if you use 'stainless' steel in an ocean environment, you need to use 316 or 316L. If you use 304, it will corrode. The 304 is stronger, but the corrosion aspect makes the softer 316 a better choice.

Hard coat anodizing the aluminum will protect it for as long as the integrity of the layer of anodizing is intact. If you break through the anodizing, for example to drill and tap a hole, all the aluminum corrosion for the entire piece will be concentrated right at that screw hole you made in the anodizing. Painting aluminum is only a good option if you use paint hard enough to seal it and not chip.
Author:  Chekika [ Fri Mar 18, 2011 6:57 am ]
Post subject:  Re: Hobie Mirage Tandem Island Problems - Rudder, Wheels, Ak
Dogslife, aka Paul Kral, just made a very interesting comment on another thread
http://www.hobiecat.com/forums/viewtopic.php?f=70&t=34203&start=15
Here is his comment:
Quote:
From the Kokopedal Video it does look like the hull mast step bolts broke off.

This is not a a good environment for a 316 stainless bolt. It is the single attachment point of the V-Brace, under stress and constantly in a wet salt environment. Stainless Steel has a stress cracking problem where it develops micro-cracks. Bolts can fail in thread areas due to machining problems when cutting the threads. The US Navy is very aware of this and stopped using 316 hardware in any loaded applications. We use 400 and 600 series bolts.

The stainless steel corrosion stress cracking can be a invisible enemy. Hobie might either have to increase the bolt size or change material in this application...

Paul...


Keith
Author:  Steve Fields [ Fri Mar 18, 2011 4:17 pm ]
Post subject:  Re: Hobie Mirage Tandem Island Problems - Rudder, Wheels, Ak
ROBO wrote:
Hi All
We do understand that this information is used by Hobie to make improvements and adjustments and we trust that answers can be provided and we can all work together to make it better for us all.

Helen and Stephen Robertson
Maclean, New South Wales
Australia


Hi Guys, Hobie Aus and Hobie USA work closely together. Each and every claim or issue is discussed at a number of levels. This is done between Hobie Aus and the dealers in Australia as well as with Hobie USA (Hobie Aus and Hobie USA are the same company). We listen and make changes when required. Many thanks for the input.
Best Regards
Steve Fields
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