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Heads Up: Duotone iBase Failure

 
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koogzah



Joined: 06 Jul 2005
Posts: 530
Location: right here

PostPosted: Mon Sep 27, 2021 5:00 pm    Post subject: Heads Up: Duotone iBase Failure Reply with quote

Realize there probably aren't many folks reading this forum, but wanted to alert any who are to a potential issue with the Duotone iBase so you can keep an eye on yours. I replaced my tendon recently after the first one cracked clear through near the midpoint. Luckily, the internal "leash" held and I was able to sail back in. Still, I had never had a tendon fail like in ~20 years of sailing. Had only ever seen some initial cracking around the bolts, indicating time to replace the tendon.

But... after replacing the broken tendon I later had a critical failure that left me stranded a couple of miles from my launch just before dark. Long story short, the cap with extension connector on the upper part of the tendon completely separated from the tendon leaving my board and rig disconnected. When I inspected things, I saw that the threaded brass sleeve and both torx bolts holding it were gone, leaving the internal leash with nothing to hold on to.

I had installed all new supplied bolts in the upper and lower ends of the replacement tendon, using blue Loctite and torquing to ~6ft lbs. No idea how this failed, but possibly on of the bolts sheared off, allowing the sleeve to slide through the hole on the other side.

After some desperate adrenaline-powered freestyle I was able to barely catch my board as it blew away downwind and then swim it back and lash it to the mast base with some spare line I carry with me. it was tricky to waterstart and sail with the loose connection, but I was able to make it back home just as the sun was setting. There was some damage to my board from the bottom of the extension scraping back and forth.

If you use a Duotone iBase, definitely inspect the tendon regularly for cracking and check the 4 bolts at the top and bottom to make sure they are still there and not loose. Personally, I'm moving on.

Hope someone finds this helpful. I'll attempt to post some links to pictures.

https://drive.google.com/file/d/1-79oEQWgvk9jWPYiCIT9oGf6AwSQY1Ax/view?usp=sharing

https://drive.google.com/file/d/13tcBltt-UI7vDA5bnr3OAd7P6R-x7DIC/view?usp=sharing

https://drive.google.com/file/d/1-zhfuCxZ2T5wlbr4_4zE5rdpejU02cWT/view?usp=sharing
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joethewindsufa



Joined: 10 Oct 2010
Posts: 1156
Location: Montréal

PostPosted: Tue Sep 28, 2021 7:56 am    Post subject: Reply with quote

glad no-one was hurt in this mishap
when I tested a DIV2 board, the board was so floaty and the wind good that I could NOT catch the board when the sail and board separated
almost got hypothermia

the most important part of our equipment and it failed = NOT GOOD Sad
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surfsuppp



Joined: 11 Feb 2016
Posts: 90

PostPosted: Tue Sep 28, 2021 9:57 am    Post subject: Re: Heads Up: Duotone iBase Failure Reply with quote

koogzah wrote:
Realize there probably aren't many folks reading this forum, but wanted to alert any who are to a potential issue with the Duotone iBase so you can keep an eye on yours. I replaced my tendon recently after the first one cracked clear through near the midpoint. Luckily, the internal "leash" held and I was able to sail back in. Still, I had never had a tendon fail like in ~20 years of sailing. Had only ever seen some initial cracking around the bolts, indicating time to replace the tendon.

But... after replacing the broken tendon I later had a critical failure that left me stranded a couple of miles from my launch just before dark. Long story short, the cap with extension connector on the upper part of the tendon completely separated from the tendon leaving my board and rig disconnected. When I inspected things, I saw that the threaded brass sleeve and both torx bolts holding it were gone, leaving the internal leash with nothing to hold on to.

I had installed all new supplied bolts in the upper and lower ends of the replacement tendon, using blue Loctite and torquing to ~6ft lbs. No idea how this failed, but possibly on of the bolts sheared off, allowing the sleeve to slide through the hole on the other side.

After some desperate adrenaline-powered freestyle I was able to barely catch my board as it blew away downwind and then swim it back and lash it to the mast base with some spare line I carry with me. it was tricky to waterstart and sail with the loose connection, but I was able to make it back home just as the sun was setting. There was some damage to my board from the bottom of the extension scraping back and forth.

If you use a Duotone iBase, definitely inspect the tendon regularly for cracking and check the 4 bolts at the top and bottom to make sure they are still there and not loose. Personally, I'm moving on.

Hope someone finds this helpful. I'll attempt to post some links to pictures.

https://drive.google.com/file/d/1-79oEQWgvk9jWPYiCIT9oGf6AwSQY1Ax/view?usp=sharing

https://drive.google.com/file/d/13tcBltt-UI7vDA5bnr3OAd7P6R-x7DIC/view?usp=sharing

https://drive.google.com/file/d/1-zhfuCxZ2T5wlbr4_4zE5rdpejU02cWT/view?usp=sharing
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dhmark



Joined: 04 Sep 2007
Posts: 364

PostPosted: Thu Sep 30, 2021 10:31 am    Post subject: Reply with quote

I am finishing first season using tendon system after 20+ years of no-problem rubber UJ (using ratchet extension which is nice), but I am concerned about 2 issues with tendon (using Chinook). I see that the safety line attachments are firmly looped through solid metal.

I know that tendon failures tend to occur in the holes, but these are not visible without disassembling, how does one check?

If a tendon does fail on the water, and safety line is needed to keep everything together, is some board damage inevitable, metal parts scraping on board surface?

DM
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NOVAAN



Joined: 28 Sep 1994
Posts: 1422

PostPosted: Thu Sep 30, 2021 10:43 am    Post subject: Reply with quote

I sailed back on the hour glass rubber tendon after a failure with no damage. Not sure about these.
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feuser



Joined: 29 Oct 2002
Posts: 1507

PostPosted: Fri Oct 08, 2021 4:49 pm    Post subject: Reply with quote

The safety lines connecting the top and bottom cups holding the tendon should keep the sheared-off end on top of the pressure plate. If not, they're way too long.
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manuel



Joined: 08 Oct 2007
Posts: 1126

PostPosted: Sat Oct 09, 2021 10:59 am    Post subject: Reply with quote

Session that you'll remember!

Any base can fail in one way or another. Sometimes it's factory issue, other times design.

If you like tendons and euro pin, although a bit heavy the Chinook SS euro tendon base is the one I recommend.

More here: http://windsurfing.lepicture.com/tips-and-tricks/

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koogzah



Joined: 06 Jul 2005
Posts: 530
Location: right here

PostPosted: Mon Oct 11, 2021 11:06 am    Post subject: Reply with quote

feuser wrote:
The safety lines connecting the top and bottom cups holding the tendon should keep the sheared-off end on top of the pressure plate. If not, they're way too long.


The Duotone "safety line" is inside the tendon and attached to the ferrules on top and bottom. If one of 4 bolts shears or loosens and a ferrule slides out, the safety line is... not safe. It is useless. Looks cool but not a "robust" design.
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koogzah



Joined: 06 Jul 2005
Posts: 530
Location: right here

PostPosted: Mon Oct 11, 2021 11:12 am    Post subject: Reply with quote

manuel wrote:
...the Chinook SS euro tendon base is the one I recommend.


That is what I went with after comparing to my old Streamlined. Heavy but solid and very easy tendon replacement process. That is the other major problem with the Duotone. Replacing the tendon is a but of a pita that requires using two torx keys.
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outcast



Joined: 04 May 2004
Posts: 2722

PostPosted: Mon Oct 11, 2021 6:48 pm    Post subject: Reply with quote

replace the tendons when you do smoke alarm batteries Smile

I do 1 year....maybe 2 max....yes, disassemble and check, any hairine and it goes in deep reserve pile of old windsurfing crap bin

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