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PostPosted: Sat Nov 25, 2006 2:31 pm 
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The mast hole cracked on the aft sprocket during normal operation with turbo fins the second day of use (after approximately 5 miles). I'm hoping it was from undetected damage which could have occurred while using the standard fins as I have not had a fin strike with the turbos. Just want to make sure others have not had the same problem which could indicate overstressing with the turbos. The $10 sprocket was easy to replace.
Greg


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PostPosted: Sat Nov 25, 2006 9:06 pm 
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Location: Escondido
It's possible to inadvertently crack the the mast hole when mounting the Turbofins by over tightening the Allen head screw (anything much beyond snug). The crack doesn't show up right away, but develops under use.

The instructions should caution against this, but I'm not sure that it does.

It's also a good idea to inspect those screws occasionally -- make sure they're holding the masts snugly and not backing out.

The old cotter pin connection (used in the earlier stainless steel versions)was nice because you couldn't screw it up -- couldn't be overtightened and wouldn't back out! 8)


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 Post subject: no worries
PostPosted: Sun Nov 26, 2006 10:03 am 
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Joined: Thu Jul 27, 2006 4:50 pm
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Location: sacramento california
I probably have a couple hundred miles on my turbo fins so far (Aug 06) with 5 different users in our tandem, and not one problem yet.
I also have not stripped out the nylon drum and "pedal length" adjustment holes, due to crank arm flexing and subsequent hole skipping, from the increased torque loads while using the Turbo fins, nor cracked or bent any other drive parts so far either. I have also bumped the bottom with the Turbo fins a time or two and noticed no significant damage to the sails aside from small scuff marks . To date, my tandem sets of Turbo fins have proven to be reliable as well as durable. I did read all the posts on this forum prior to mounting the Turbo fins and I think that helped avoid all of the installation pitfalls, mistakes, and subsequent failures etc. at least up to this point in time 8)
kepnutz


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PostPosted: Sun Nov 26, 2006 7:18 pm 
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Cap'n Kep,

It's good to hear you've done so well with your drives so far. Since they've developed no problems, it's probably OK to launch somewhere else besides your swimming pool and put some wear and tear on them. 200 miles worth of laps must be getting boring by now. :wink:

PS: congratulations on your promotion! 8)


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PostPosted: Mon Nov 27, 2006 1:18 pm 
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Joined: Sun Apr 03, 2005 5:21 pm
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gpru wrote:
The mast hole cracked on the aft sprocket during normal operation with turbo fins the second day of use (after approximately 5 miles). I'm hoping it was from undetected damage which could have occurred while using the standard fins as I have not had a fin strike with the turbos. Just want to make sure others have not had the same problem which could indicate overstressing with the turbos. The $10 sprocket was easy to replace.
Greg
My sprocket cracked at the mast hole within the first week. It was assumed I over tightened the set screw. But, I have set screws constantly coming loose. Hmmm.


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 Post subject: cool pool
PostPosted: Mon Nov 27, 2006 4:10 pm 
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Location: sacramento california
Hi-Ya Roadster...
I guess you're right, perhaps I should make an extra effort to try someplace new for a change. :wink:
I spoke with my neighbor today and they said after the Hollydaze I could start using their pool for my next 200 miles as long as I didn't let the dogs out.. :lol:
Kepnutz


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PostPosted: Sun Dec 03, 2006 5:38 pm 
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Joined: Fri Aug 04, 2006 4:48 pm
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Location: Virginia Beach, Va.
Mine broke on me as well it was the rear sprocket. The rep said I had to have hit something and stressed it but the fin hasn't got a mark on it except a small stress crack right at the top were the mast comes out.

I was pedaling while sailing in order to maintain rudder control on my Island while filming, I think I can even tell when it went while wacthing the video. It started slapping the dagger board.


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 Post subject: Over Stressed
PostPosted: Sun Dec 03, 2006 8:55 pm 
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Location: sacramento california
Hi-ya G-Wizard
Thank you for the posts and videos on your AI excursions , you have really covered a lot of interesting concerns in a very short time. 8)
I was wondering , since you did not hit anything , if the higher speeds possible with with the A.I , in conjunction with the larger surface area of the turbo fins and longer masts might be putting more torque on these drive parts than the engineers planned for using pedal power only?
While using the turbo fins under pedal power alone, perhaps the lower speeds do not stress the sprockets nearly as much as the higher speeds of the AI under sail which average two times more and change. Wouldn't the constant higher speeds add more torque and leverage up the fin mast to the sprocket area? Similar perhaps to the difference between sticking your hand out the car window at 40 mph then again at 85 mph, one can really feel the difference of the large force at the higher speeds.
Most people seem to know when they hit something hard enough to bend a mast and or break a sprocket,it would almost stop the boat in its tracks I think!
I also read post's where some concerns were made that the Turbo fins were getting ripped up and showed higher wear rather easily compared to the standard fins so it seems they would probably show significant marks if run aground with enough force to damage the mast and sprocket. Therefore if you did not hit anything what else could explain the damage..assuming proper turbo fin installation?
Just my two cents and an unproven wild guess, not worth a whole lot but I thought I would toss it out there. Thanks again for all your informative posts :wink:
- Kepnutz-


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 Post subject:
PostPosted: Mon Dec 04, 2006 6:41 am 
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Location: Virginia Beach, Va.
"Wouldn't the constant higher speeds add more torque and leverage up the fin mast to the sprocket area? Similar perhaps to the difference between sticking your hand out the car window at 40 mph then again at 85 mph, one can really feel the difference of the large force at the higher speeds. "

Thats is what I'm thinking as well. On mine one side of the sprocket mast reciver is gone but my set screw is still the piece I have left. My mast fits snuggly but can be slid into place. Without using any real force

The one thing I noticed is the the set screw is at an angle so the it doesn't hit the mast squarely meaning only the bottom of the set screw contacts the steel mast.

http://i112.photobucket.com/albums/n196 ... usted1.jpg

http://i112.photobucket.com/albums/n196 ... busted.jpg

http://i112.photobucket.com/albums/n196 ... finrip.jpg

You have too look real hard to see the rip in the top of the fin, and that is the only mark on either fin.


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 Post subject: See it
PostPosted: Mon Dec 04, 2006 8:09 am 
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Location: sacramento california
Hi Ya G-man
Those are good shots. I can see the tear in the fin in the upper right hand corner where the mast exits .. I think.
At any rate, that would seem to be the odd place to tear a fin from a bottom strike IMHO. I know my masts went in the drives very very tightly,and the set screw was snugged up just to lock it into position so if my set screw is hitting at an angle it looks to be working ok so far. The masts still appear to be very tight on both after many miles at 4 and 5mph. If the mast sprocket hole was to be wallowed out by higher forces and became loose it might be a different result all together. Fortunately it is not an expensive part , but on the other hand maybe that is partly to blame for the subsequent failure. Perhaps the turbo fins need to be lab tested again to failure at the higher A.I. forces to determine if there is a connection there. Hope you get it all sorted out and I know from other posts that Hobie takes good care of its peeps. :wink:
-Kepnutz-


Last edited by kepnutz on Mon Dec 04, 2006 2:32 pm, edited 2 times in total.

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 Post subject:
PostPosted: Mon Dec 04, 2006 9:31 am 
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Joined: Fri Aug 04, 2006 4:48 pm
Posts: 129
Location: Virginia Beach, Va.
"Hope you get it all sorted out and I know from other posts that Hobie takes good care of its peeps."
I do want to make clear that Hobie is sending me replacements, both they and my Dealer have been great considering that I am admitedly pushing the Island pretty hard.

I bought it to sail and I sail for fun. I tried sailing in calmer waters, it has a nice calming effect, not really why I sail. I bought the Island to get and keep my blood pumping. It may well be that the turbo fins and the Island might require some parts of the drive to be made more bullet proof.

gwiz


Last edited by gwiz on Mon Dec 04, 2006 12:48 pm, edited 1 time in total.

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 Post subject: Re: See it
PostPosted: Mon Dec 04, 2006 10:55 am 
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kepnutz wrote:
...Hobie takes good care of its peeps. :wink:

Hi Kep,

What's a peep? Is it anything like a pimp or a perp -- or a chirp? The only peep I know of is an Easter marshmellow bird - one of my favorites!

Is this something I should sign up for also? 8)


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 Post subject: Ya knucklehead
PostPosted: Mon Dec 04, 2006 2:30 pm 
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Posts: 461
Location: sacramento california
Hi-Ya Roadie
You are a Hobie peep...short for people... as in tribe , member , loyal fan , satisfied customer..etc etc..aka "Peep"..! You could also be a perp but you dont seem like a pimp and you are already signed up :wink:
-kepnutz-


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 Post subject:
PostPosted: Mon Dec 04, 2006 7:44 pm 
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Joined: Thu Jul 27, 2006 8:07 am
Posts: 56
Location: Corpus Christi Tx.
sounds like dittos to me. :idea:

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