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Black chinese tendon
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manuel



Joined: 08 Oct 2007
Posts: 964

PostPosted: Wed Sep 18, 2019 9:47 am    Post subject: Reply with quote

Bad batch, unlikely, although I don't remember whether I bought them from the same exact vendor each time, I did purchase 2 at a time over the years. I have about 7 cracked ones in my box (in 6.5 years of sailing here, 190-220 sessions per year). The last tendon I purchased was certainly from a different vendor and was a tighter fit to begin with, now wearless still after a couple of months.

It's hard for vendors to know manufacturing date. I do know that if I leave them in a box with silica gel after 2 years they are dried out on the outside and develop cracks everywhere. I think possibly the most important thing is to have the tendons in as tightly as possible so that the base holds the tendon when prying on it versus the holes. I replaced worn out parts and used to use shims to make a tight fit.

After using shims I realized tendons lasted longer 6 months versus just 3. They never cracked in the middle always around the holes. Then, I decided to purchase a new streamlined base. Same problem, possibly 4 months lifespan. And worse, when top play develops in the plastic US cup there's no way to tighten the upper nut as it bottoms out. So now I have a nearly new base with huge play on the upper cup... useless and therefore back to the old one!

Since it's been harder to source Streamlined tendons, I was "forced" to go either Chinook or generic Chinese. And since Chinook required shims, I am trying simply Chinese.

Besides taking the tendon out for routine inspection, I bend them to rinse inside after each session and check gaps around the base. If it's tight, there's no crack around the holes. A gap will eventually appear as the tendon starts shrinking.

I've had one fail, I think out of my new base(!) and it's rubbery enough that it didn't damaged the deck. It was a late hit on a big wave gone wrong type of event while the tendon was quite badly cracked (wanted to see how far I could "stretch it" Very Happy !!! No damage to the deck as there's still some rubbery part left in both sides of the base. The safety line did its job unlike the Boge safety's strap which left me to swim with just my rig, oops!

LONG STORY Very Happy !!!


Last edited by manuel on Wed Sep 18, 2019 9:57 am; edited 1 time in total
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fathomfathom



Joined: 25 Jul 2005
Posts: 47

PostPosted: Wed Sep 18, 2019 9:52 am    Post subject: Reply with quote

Thanks Manuel

Just wondering if you can put a big washer in the US cups to decrease the play. Lots of play in my US cup bases but don't seem to get much worse over time.

What do you think of using mechanical joint instead. Would they be more reliable/longer lasting. I've been using them with foiling in addition to the SurfBent.
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manuel



Joined: 08 Oct 2007
Posts: 964

PostPosted: Wed Sep 18, 2019 10:08 am    Post subject: Reply with quote

I often myself go to my own website to see what I found out about a certain subject because I write things when they are fresh in my head, look for the mast base section:

http://windsurfing.lepicture.com/tips-and-tricks/#faq-gear

The mechanical version feels super heavy, has direct connection to the board so it's harsher on both the deck and the hull when hitting chop and possibly ankles. It may get stuck (I'm waterstarting tens of times in a session and not necessarily in the friendliest conditions!!!!).

It comes with a single-bolt design only, so possibly more stress on the mast track, may also disconnect when it slips off the track completely. It also sits higher on the deck (I believe the streamlined is the lowest mast base). Not sure about tightening up the play on the upper part.

Shimming may not help the play on some cups because it's dependent on the nut bottoming out on a brass-ish cylinder. The plastic wears out more than the metal cylinder. One can use a plastic washer between the middle part of the base and the cup, this would work.

One thing to keep in mind when tightening the top nut is to make sure the plastic cup still has some good thickness, these break sometimes and no safety line will help there.

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fathomfathom



Joined: 25 Jul 2005
Posts: 47

PostPosted: Wed Sep 18, 2019 11:18 am    Post subject: Reply with quote

I did read your blog and tips, very useful.

There were scant description re long term use of the mechanical joint hence the question.

BTW mechanical joint can be used with the Chinook 2 bolt base (that's what I'm using). I haven't got a chance to try them in waves yet for the exact reason you mention re shock absorption.
I use tendon only in waves.
I had to shave a bit of the Streamline orange tendon to fit inside the Chinook joint but seems to be lasting longer than the black Chinook tendon (both mid section and esp no crack at the internal bolt hole).
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dllee



Joined: 03 Jul 2009
Posts: 4595
Location: East Bay

PostPosted: Wed Sep 18, 2019 11:41 am    Post subject: Reply with quote

Bought mech base in May.
30 foil days for sure.
About 30 windsurf days, mostly 4.5 to 5.2 and 80-94 liter boards. I jump a lot.
The base might have tightened up a bit from new, or friction from having never been rinsed and always used in salt water.
Seems about the same ride as my u joints.
I have not ridden any board over 64cm wide with the mech base. Most of my smaller boards are 54-55 wide.
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dllee



Joined: 03 Jul 2009
Posts: 4595
Location: East Bay

PostPosted: Wed Sep 18, 2019 11:48 am    Post subject: Reply with quote

Oh, I was using Chinook mech base in early '90's for Speed Trials.
Seemed ok, but I had some slow times, and coupled with all the flak from fellow competitors about rough on boards, and me giving up on trying for speed, they got lost in the windsurf bin thru multiple moves and relocations.
I was working at windsurf shops, so never worried about old gear.
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manuel



Joined: 08 Oct 2007
Posts: 964

PostPosted: Wed Sep 18, 2019 12:03 pm    Post subject: Reply with quote

No problem, I'm happy to clarify Smile Depending on the type of use, one can choose their preferred base or even switch between different ones.

I love tendons because I can keep it tight, it's low to the deck, absorbs impacts ok, light, easy to maintain, reliable, can use double-bolt, safest to fail, fast rig response, resists board flips.

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