I inspect mine before the cold season starts and additionally mid-season if foiling frequently, because as others pointed out, the problem starts to manifest around the drilled hole area.

Then I replace it regardless of use after two years at the latest. Plus I carry a whole, spare, detachable mast foot in my Camelbak :) If you already have the one where the upper part can be removed from the mast foot plate, you can have just that part as a spare in your harness / impact vest / Camelbak, and one day it might save the session.

Mast track too forward? This too can be solved, been there, done that:
- buy a Surfbent nose protector
- crash and rip out the mast track as a result of leverage
- install a new mast track, which you can place further back :)

Not the cheapest option though, but it works.

Inspected before every session. Replaced as needed or every few years. Running a few different universals. So far, no total failures. But have cracked both the streamline tendon and chinook hourglass models. New Chinook black tendons don't fit the too old tendon uni. Not sure when the change occurred. . Using the Chinook ProFlex on the foil board. Like an earlier poster lost a nut one day. Luckily the bolt stayed in place. Contacted Chinook. They sent me a bunch of nuts and bolts for the uni. Different sized nuts and bolts used on the uni. I now check those bolts. No real big deal.

Decided to buy a spare Streamlined Quick-Lock Universal, the top half is now one piece stainless steel, Loopeewindsurfing.com had it for $55, seems reasonable and very reasonable shipping, and can carry with me in case I break a tendon on the water. Will use existing one until it breaks, and let you all know how long it lasted!

Sandman1221 said..
Decided to buy a spare Streamlined Quick-Lock Universal, the top half is now one piece stainless steel, Loopeewindsurfing.com had it for $55, seems reasonable and very reasonable shipping, and can carry with me in case I break a tendon on the water. Will use existing one until it breaks, and let you all know how long it lasted!

Swapping a universal on a foilboard out on the water will be quite the exercise in frustration. Might want to try that near the shoreline before committing to this plan. Much better to replace now and avoid the failure

Here is a pic of my well used Streamlined mast base universal next to a brand new one, tendon on old one is definitely a little swollen, but otherwise looks good. How swollen do the tendons gets before coming close to failing?

Hydrosurf said..
Just bend over and check for cracks

Thanks Hydrosurf, just checked under a lighted magnifying glass and there were no cracks. Will keep checking once in a while.

WillyWind said..
People: a u join tendon costs 30-50 dollars. A tendon failing can damage your 2-3k board, make it a pain to go back to shore (potentially needing to ditch your 1 to 3k rig), and worse-case scenario, it can cause a bad fall and injury.
Replace it when it has cracks, looks discolored, or when it looks swollen like the one sandman is going to keep using. even if you sail a ton I think you might need to replace it once a year.

Thanks WillyWind, now I do only foil so that should help, but if it swells anymore will replace. Going to check the thickness with a caliper and write it down.

Well this is interesting, the new tendon is 0.8" in diameter, the two 5-6 yr old ones are 0.795" in diameter, so the old ones are a little thinner at the middle. But never measured them when new.

segler said..
My tan tendons also swell a little, and stay that way for months/years. I always check for cracks. No cracks. I checked it yesterday again before heading out onto the mighty Columbia. No problems.

Thanks segler, good to know. Now I am wondering if the swollen appearance is actually due to compression, the tendon gets compressed more around the top and bottom by the respective cap when it is bent over, and that makes the middle look swollen, because based on my measurements the middle is not swollen compared to a new unused tendon.

And be safe as always on the Columbia, it is a powerful river!

And the new version of the Streamlined universal, in addition to now having a SS top cap, also has a black colored friction disk on the bottom cap to prevent wear between the bottom cap and the Quick release SS mast base plate. The SS top cap mates with the extension which has a plastic bottom cap which serves as a friction disk.

Sandman1221 said..
Formula, thanks again, yes the spare I just got saved the session! Busted!, was getting ready to do any easy beach start, ala Guy Cribb, and the ~5 yr old universal tendon broke. Fortunately I had the spare new universal in my Yeti Sidekick strapped to my waist, and swapped them out in the water without having to get out of the water!

Interesting picture. I doubt that a pre-session visual inspection would have seen any cracks on the rubber.
You got people who have lasted 15 years and this one is 5 years. I think it is worth coming up with a maintenance schedule for replacement and trying to stick with it.
I also wonder about having a spare Tendon that you have had on you for a couple of years. Would that not also degrade?
Yeah, you could replace it on the water and get yourself in. But wouldn't it just be better to spend a little bit of money every year or every other year than dumping cash on a Streamlined mast base?
I guess it might come down to how far offshore you head or how dependent you are just on yourself to get home. Usually, I am within swimming distance of land so if it all went bad then I "think" I could get myself back in (the rips/tides are not that much of a problem).
Just not sure why you would try not to promote just forking out $20 and replacing the tendon.
Of all the stuff that can go wrong with windsurfing gear, I think it is wise to promote carrying some extra rope and trying to perform maintenance when you can.

Paducah said..

Henners said..
....Just not sure why you would try not to promote just forking out $20 and replacing the tendon.
Of all the stuff that can go wrong with windsurfing gear, I think it is wise to promote carrying some extra rope and trying to perform maintenance when you can.

This and what WillyWind said. It's *ing $20. Replace it regularly. Tendons are made of material that left on their own and stored in a dry, dark spot will still degrade. Many materials have a finite term of use. Tendons, aluminum spars in airplanes, auto components. Even if it looks okay, just replace it. It's called a maintenance schedule. You replace s**t before it breaks.

If you are carrying rope, it should be to help someone else out or give them a tow; not because of your dodgy polyester downhaul line. Spend $6-8 on good formuline and be done with it. You've spent as much as $6-10k on your gear but the two things that easily break, you saved $25?

Rope wise it can be dam handy. I had a broken boom clamp on the water and managed to repair it with the batten tensioner. I used the rope to secure the tensioner key to my arm otherwise I would have lost it, in the small wind swell and I would have had to swim my gear back. As a backup, I think I could have used it to secure the boom back to the mast. So it is just not for helping your mates out or finding a kiteboard and no kiter.
At the present time, I reverse my ropes each season and replace them every two years. If the rope is buggered before then I replace it.
I've been broke and $20 to $30 seemed like a lot of cash, I have even thought about carrying a spare tendon with a few Allen keys. It is each to their own, maybe you sail in a lake or a river that is not freezing, and you got old gear that you don't mind trashing. I usually sail by myself, have limited time, and have to get back on time.
Not sure where you are going with that meme, a little bit on the dumb side if you are directing it at me as I am saying replace the tendon every year.

Henners said..

Paducah said..

Henners said..
....Just not sure why you would try not to promote just forking out $20 and replacing the tendon.
Of all the stuff that can go wrong with windsurfing gear, I think it is wise to promote carrying some extra rope and trying to perform maintenance when you can.

This and what WillyWind said. It's *ing $20. Replace it regularly. Tendons are made of material that left on their own and stored in a dry, dark spot will still degrade. Many materials have a finite term of use. Tendons, aluminum spars in airplanes, auto components. Even if it looks okay, just replace it. It's called a maintenance schedule. You replace s**t before it breaks.

If you are carrying rope, it should be to help someone else out or give them a tow; not because of your dodgy polyester downhaul line. Spend $6-8 on good formuline and be done with it. You've spent as much as $6-10k on your gear but the two things that easily break, you saved $25?

Rope wise it can be dam handy. I had a broken boom clamp on the water and managed to repair it with the batten tensioner. I used the rope to secure the tensioner key to my arm otherwise I would have lost it, in the small wind swell and I would have had to swim my gear back. As a backup, I think I could have used it to secure the boom back to the mast. So it is just not for helping your mates out or finding a kiteboard and no kiter.
At the present time, I reverse my ropes each season and replace them every two years. If the rope is buggered before then I replace it.
I've been broke and $20 to $30 seemed like a lot of cash, I have even thought about carrying a spare tendon with a few Allen keys. It is each to their own, maybe you sail in a lake or a river that is not freezing, and you got old gear that you don't mind trashing. I usually sail by myself, have limited time, and have to get back on time.
Not sure where you are going with that meme, a little bit on the dumb side if you are directing it at me as I am saying replace the tendon every year.

I was agreeing with you which is why I quoted "....Just not sure why you would try not to promote just forking out $20 and replacing the tendon. " and why I said, "This and what WillyWind, said.", internet parlance for agreeing with the referred comment.

I sail part of the year in 8C and less water and air. I'm mindful that breaking something is going to lead to a very long day/evening in hostile conditions. So maybe pack a line for the really unforseen but don't pack a line because you look at that frayed outhaul/downhaul and think, "yeah, looks like it'll hold one more go."

Henners said..
I'm sorry, I'm just a bit of a sensitive flower.
Wishing you good wind, free time to get out there, and go for a flight.
I am interested in what conditions Sandman is in and why he wants to keep a spare rather than replace it.
Pre-children a few of us were planning to windsurf behind a local ferry and go to an island about 2 hours away. Part of the plan was to carry a spare tendon and a GPS phone. So I can see the need in that situation.
2 hrs on one tack what was I thinking? I'm not sure if even young me could have done it.

All good. Sorry I wasn't more clear. I agree with you for the 2 hour trip. That's when you plan for the backup to the backup.

Wishing you the same.

Chinook and streamlined have the holes in the same locations

Not quite the failure we're thinking of but...