After my recent shark experience I thought it was a particularly good time to inspect my unis. I’ve always been pretty good about eyeballing them and giving them a bend to see if any cracks or rot are visible, but a post in the Live to Sail blog was taking uni inspection to the next level. In short, Live to Sail's George (under the guidance of Lost In Hatteras' Andy) disassembled his unis to check out the portion of the tendon where the bolt passes through.
Because I worry about gear failure (and now I REALLY worry about gear failure) I actually keep a separate uni for ocean and “far from shore” sessions…it’s always my newest uni. I save my older ones for sailing all the spots where a breakdown would be no big deal (I still inspect those unis too, mind you.) And every few years I buy a new uni which bumps the top one down the uni heirarchy, and the oldest goes into the trash.
I was inspired by both the shark and the Live to Sail post, so I took out my tool box and prepared to disassemble and inspect. To my horror, the ocean uni (aka the Shark Session uni) was missing one of its retaining nuts. The bolt holding the tendon to the bottom of the uni was being held in place by friction alone. That was Bad. Then I slid out the bolt to see what condition my newest tendon was in…it was cracked halfway through.
So I drove to the windsurfing shop to get parts from Jon Ford. While installing the new tendon with my new nut, I asked Jon if it was possible to overtighten.
“Make sure its tight, but you don’t want to really crank it,” he said, about a second after I’d really cranked it, and managed to split the top of the uni.
So I ended up buying a brand new uni. My new ocean uni.
(photo swiped from Live to Sail: The tendon looked great until George and Andy disassembled the unit.)
yup, i was pretty horrified too when i saw the state my uni's were in. I'll be checking my all the time, which means don't use loctight.
Posted by: george markopoulos | June 30, 2009 at 01:49 PM
Just make sure to replace the safety line with a spectra line and you'll always be able to sail back even if the tendon breaks.
Posted by: gp | June 30, 2009 at 07:32 PM
Dude, that just happened to me about two weeks ago! I was leaving Dougs after an intense 3.7 day and I looked down at my rig to see the uni was splitting. I was sooooo lucky it didn't pop on the water!
Posted by: jon sassone | July 01, 2009 at 01:17 AM
I use the most recent tendon from Chinook (http://www.chinooksailing.com/products/product_info.php?cPath=2_31_32&products_id=109) which has a sturdy safety band instead of a thin rope. That should allow you to sail back to the beach in case of a joint breakdown....does anyone have experience on the reliability of the new joints?
Posted by: Tony | July 01, 2009 at 11:54 AM
I bought the same one as a replacement, Tony...may they serve us well! Meanwhile I regularly check the retainer line and replace as necessary. I once had to sail about five hundred yards with just that length of Marlow for a uni...it worked well. You can stick a booty under the damaged UJ to prevent it from tearing up the board's deck.
Posted by: michael | July 01, 2009 at 12:22 PM
Interestingly, I've found that the yellow Streamlined tendons tend to last _a_lot_longer_ than the black Chinook ones. YMMV, but for me, that's held true so far. I guess Dave Dominy knows from urethane...
Posted by: Andreas | July 01, 2009 at 01:41 PM
U can use blue 242 locktite, NON permanent. my Fiberspar also lost a nut, most disturbing. AND the PIN that goes into the extension broke, a bad design of a round pin screwed into a square hole-doh!! oh yeah, broken 2 of their tendons as well. so inspect and be careful w the nuts!!
Posted by: Kevin O | July 01, 2010 at 09:18 AM