Tendon in the Chinook Mast base
Wind
sailing, resulting in a near-loss of a sail, followed by a long walk
to shore...
I'd rather not wait until mine breaks while I am out sailing, so the
question for the group is: How often should I be replacing the tendon
on my mast base? Is anyone replacing the tendons in their bases?
Cheers,
Gene
Charles Ivey
and I would not risk it when you do see this. Just inspect the tendon with
the rig laying over so it is stretched and then move the rig around
observing all sides of the tendon. It might scare you to act if you see any
cracks or separations. I like tendons, but if sailing in a challenging
situation where there is risk (like off shore -- next stop Cuba, or really
cold water), I use the old mechanical joint and frequently inspect the
insertion plug to make sure the bolt and screws are secure. How often you
replace is not as important as inspecting your tendon frequently in my
opinion. My experience is several tendons have become worn and problematic
after one season, others have lasted longer.
CI
"Wind" <wi...@kalmius.com> wrote in message
news:ee5b066b.03082...@posting.google.com...
sailquik (Roger Jackson)
It's a good idea to check the tendon as Charles suggests, nearly every
time you sail.
I use "genuine" Streamlined tendons, and they seem to last virtually
forever.
You can tell if it's the genuine article by the little Streamlined logo
(a circle with
a line through it) penned onto the tendon itself.
You can see the logo on the Streamlined joint at:
http://www.streamlined-usa.com/mastfeet.htm
Streamlined uses cast metal "cups" and solid stainless steel cross pins
with tapped
holes in the ends for the retainer screws. I've never had a failure with
this system,
but some of the "imitators" products have failed.
The cross pins are not solid, but have a sleeve with a screw that goes
all the way
through the cup and the tendon. These have failed a number of times.
Another thing to watch for is if the special (I say special because I've
tried to find
some to buy) flat head SS allen screw that holds the metal cup to the
twist plate, and
also (same type screw) to the mast extension adapter on the top gets
loose, it indicates
quite a bit of wear on the "seat" for the flat head screw in the bottom
of the cup,
or simply that the nut has backed off and is no longer holding the FH
screw in contact
with the seat in the metal cup. If it's worn, it's a good idea to replace
the whole tendon
and cups assembly.
If the nut has simply backed off, then take it apart, clean it all up,
rinse it in LocTite
primer, and then apply a small quantity of Loc-Tite (use the stud and
bearing mount
grade as some of the prevailing torque grades seem to let loose in this
application)
and reassemble so there is just enough clearance between the angle on the
Flat head
Allen screw and the seat in the bottom of the cup for them to turn
freely, but not
enough clearance so they can "rock or tip". Let the Loc-Tite set up and
you should
have a very "long term reliable" mast foot.
Hope this helps,
Roger
Mike F
> sailing, resulting in a near-loss of a sail, followed by a long walk
> to shore...
Didn't know Jesus shredded. '-)
But, seriously, folks ...
1. Use a webbing joint-saver so you can sail a severed joint to shore.
2. I'm wondering whether you're using the word, "tendon" deliberately, or
maybe are calling a rubber hourglass a "tendon". If so, the rubber
hourglasses can snap even when new. See #1.
Mike \m/
RMoore 41
in the old rubber hourglas. So look for anything suspect and replace
beforehand. The tendon should have a rope lanyard between the two ends so that
will help in case of failure. but the bottomline is that the tendon joints are
better than the rubber hourglas and for sure better than the mechanical u
joints of years past. Stiffer and more performance. I use the Streamline ones
sold by Murray's Marine and they last for a long time. RON
Ellen
I'm still using tendons that I've owned for 5 or 6 years. I check
them often. The black rubber hourglass joints are far more likely to
crack and break than the tendons. I've only seen one problem with those,
and that was from another part coming loose rather than breakage. I"m
sure I"ve just been lucky, but I'd think you'd be able to get several
years of use from one if you are a weekend warrior. Maybe less if you
sail far more frequently.
We had a related problem last weekend but it wasn't a tendon
breaking. The base had come loose and the whole thing pulled out of the
mastrack, resulting in a swim for the board and a search for the rig.
All were happily reunited in the end.
Ellen
Wind
Low tide :)
Mike F
better than a mechanical joint, at least the one Chinook's offered for about
a decade now? Have I overlooked an advantage of flexible widgets in my quest
for instant response, any-angle plug-in, zero maintenance, and (so far)
permanent bombproof performance, by using the mechs instead of flexible
widgets? Besides, the Hydroshok version adds deck-preserving shock
absorption and a smoother ride to the equation. Seems to me that flexible
widgets are old-fashioned.
OK ... I've got my helmet on. Fire away! Just offering an alternative and
wondering what I'm missing. I'm surprised they didn't catch on any better,
except for people who value initial price difference over performance
advantages and risk reduction.
OTOH, Chinook admits the Hydroshok center pin had corrosion problems in salt
water which could collapse the unit some day, rendering it problematic for
long-term ocean use. THAT sux even though it still sails back home just fine
if that part fails; I'll use a tendon w/o Hydroshok in the ocean, or mark
one Hydroshok for salt water use only and inspect and lube it regularly.
Mike \m/
"RMoore 41" <rmoo...@aol.com> wrote
Cliff Frost
> Gene,
...
> We had a related problem last weekend but it wasn't a tendon
> breaking. The base had come loose and the whole thing pulled out of the
> mastrack, resulting in a swim for the board and a search for the rig.
> All were happily reunited in the end.
This happened to me a couple of weeks ago as I was sailing up to the
starting line at a race. Off Crissy Field with a big honking sail (9.3)
and formula board. Can't just tilt the board on it's side to stick
the base back in the track. Lots of chop also made it fun.
I did manage to get it into the track so's I could sail back to shore before
the pack sailed down on me, but it was touch-and-go for a while and very
tiring!
It's always something... ;-)
-Cliff
Charles Ivey
mentions (circle with line -- very distinctive mark). One broke right at
the rod (screw) through the bottom and another was working fine but upon
inspection was cracked part way up the tendon. So I checked four or five of
them before leaving for a recent trip. They were all 3 years old or less
and I found another one "ready to expire." This has made me more cautious
than before.
I think your sailing area and conditions may contribute to the possible
failures. We have horridly hot weather in the summer with UV radiation off
the scale. We also unwisely put these through some rough use.
Tendons are nice and do last well, but they also fail and as Roger says, use
the good tendons for replacement.
Charles
p.s. When the old black rubber ones started cracking, they got moved to
drag boards and simulators...The true tendons are too valuable so I replace
those.
Ray Kuntz
One of the very real advantages of the Chinook mechanical u-joints that
Mike F. writes about is your ability to loosen it on the water and
adjust your mast foot placement or God Forbid reattach it, on a wide
board, if need be.
Raymond
florian
> Roger has had better luck than I with the tendons. I use the ones he
> mentions (circle with line -- very distinctive mark). One broke right
> at the rod (screw) through the bottom and another was working fine but
> upon inspection was cracked part way up the tendon. So I checked four
> or five of them before leaving for a recent trip. They were all 3
> years old or less and I found another one "ready to expire." This has
> made me more cautious than before.
Just wondeing how you check all those tendons. I found the bolts holding
the tendon in the cups a royal PITA to open - the threads must have been
drenched in what looked like epoxy (10 year-old loctite?).
Even after I took off the nuts with the nylon thread stoppers, the bolts
wouldn't budge, indtead I thoroughly stripped both philips heads. Had to
file a flat surface into the side of the bolt and use a Vise-Grip to
loosen the bolts.
To whoever assemles those things: DON'T use tons of LocTite, the nylon
inserts are plenty since there's absolutely no movement between both
sides of the aluminum cup and the bolt.
BTW: the bolts are 8-32 and are 34mm long (that is 1 11/32, Frank!), so
order part number 1351 from boltdepot.com and get a good file!
florian
Charles Ivey
appears on one side. Then I can remove the assembly, and reuse it with the
new tendon. This has worked well for me.
CI
"florian" <florian...@funnygarbage.com> wrote in message
news:20030829001...@News.CIS.DFN.DE...
florian
> I screw out the screw just a little and tap the whole thing until the
> sleeve appears on one side. Then I can remove the assembly, and reuse
> it with the new tendon. This has worked well for me.
>
> CI
Wow, no such luck here. No sleeve around the threads, either; the screw
goes right through holes in the tendon. I wonder if that's the original
streamlined assembly. Looks ancient (I bought that thing together with a
used WS Hawaii extension last year) but ironically the tendon was in
great shape.
florian
sailquik (Roger Jackson)
Do you sail nearly all the time in a freshwater lake? Charles does!
Sounds like you have the original.
I've had some with sleeves, but the most reliable have a solid rod
with tapped holes in the ends. The little screws come out nicely if you
use a bit of anti-seize compound on them, vs Loc-tite. Specially if you
use them in salt water. The metals in the cups, the pins, and the screws
are all different and galvanic corrosion can cause problems like the
screws won't come out.
Again, if you think there's Loc-Tite, warm up the screw with a tiny torch.
That softens the Loc-tite and allows the screws to come out more easily.
As stated, the screws simply holds the pin from falling out, and if you
get then nicely torqued into the ends of the pin or the seats on the
cup, they really have nothing to loosen them.
Hope this helps,
Roger
Juri Munkki
>Just wondeing how you check all those tendons. I found the bolts holding
>the tendon in the cups a royal PITA to open - the threads must have been
>drenched in what looked like epoxy (10 year-old loctite?).
>
>Even after I took off the nuts with the nylon thread stoppers, the bolts
>wouldn't budge, indtead I thoroughly stripped both philips heads. Had to
>file a flat surface into the side of the bolt and use a Vise-Grip to
>loosen the bolts.
Those small machine screws on the sides of the cup shouldn't be too
hard to open. Once open, you're left with the task of getting the
threaded tube out. This is best done with a handful of oversized washers.
You put a few washers between the screw and cup and tighten. The tube
will pull through the washers (keep them aligned properly and make sure
the tube fits through them). It's like using a cork-screw.
I tried a hammer first, but that was a _bad_ idea.
I don't think the screws holding the tendon in place need any loctite or glue.
The nice thing about the Chinook tendon is that you can replace the tendon
without touching the top & bottom of the assembly. Those 8 mm bolts need to
be tight and opening those can be next to impossible. It's far easier to
replace a tendon than replacing an hourglass universal.
--
Juri Munkki jmu...@iki.fi What you see isn't all you get.
http://www.iki.fi/jmunkki Windsurfing: Faster than the wind.
Bob Jacobson
Marina. Myself, I use the ole hourglass with the safety webbing. Replace
once a year with new hourglass at about $18 = Cheap Insurance.
"Ellen" <eleanor...@yale.edu> wrote in message
news:3F4E555D...@yale.edu...
Bob Jacobson
hasn't seemed to be that much difference in performance. What's the deal?
"Charles Ivey" <charl...@cox.net> wrote in message
news:MXu3b.47361$0u4....@news1.central.cox.net...
Dustin T. Hughes
They do not have as soft and forgiven feel like the rubber u-joints.
Only one thing is to make sure you have a pad to cover it. I almost
lost my little toe in a jibe about 2 months ago. I received 5 stitches
in my foot because of this issue. Yes, I still sail my tendon joint
and love it, but make sure to use a base pad or booties. You might
lose a toe one day with the tendon joint. I had too much bad luck with
rubber u-joint braking and coming apart.
Every one has their own comments about the tendon vs. rubber u-joint.
Own both and use the one that best for the condtions that day. Just
make sure to use a base pad.
Make sure you inspect all of your gear before you go out. Know what
condition your gear is in before you put yourself in hazardous
conditions. Know your limits of your ability. Safety is the number
important thing while enjoying a good session.
D. Hughes
RMoore 41
seen one for years. I had a couple of those when they came out, what I didn't
like was the clunk feel when sailing in choppy water and just a basic
sloppyness down there when sailing around. Once they got a few miles on them
they seemed to get sloppier. Anyway, the tendons are stiff and have a positive
feel, that is why most sailors use them and use them with few problems. As far
as dissing Mikes point of view, he is the self proclaimed high wind wizard and
if those things work for him great. I will stay with the tendons. RON
florian
> Hello Florian,
> Do you sail nearly all the time in a freshwater lake? Charles does!
> Sounds like you have the original.
> I've had some with sleeves, but the most reliable have a solid rod
> with tapped holes in the ends. The little screws come out nicely if
> you use a bit of anti-seize compound on them, vs Loc-tite. Specially
> if you use them in salt water. The metals in the cups, the pins, and
> the screws are all different and galvanic corrosion can cause problems
> like the screws won't come out. Again, if you think there's Loc-Tite,
> warm up the screw with a tiny torch. That softens the Loc-tite and
> allows the screws to come out more easily. As stated, the screws
> simply holds the pin from falling out, and if you get then nicely
> torqued into the ends of the pin or the seats on the cup, they really
> have nothing to loosen them. Hope this helps, Roger
>
I sail in salt water only and I believe that's where the previous owner
used the mast foot it as well.
You are right about galvanic corrosion; Aluminum is a bit more towards
the corroding end of the ladder making it an Anode to the stainless
steel used in the screw. That explains the buildup on the bolts.
The screws actually are number 8 machine screws that go all the way
though the aluminum cups. No rods, no sleeves here. I am also quite sure
that something else than loctite was used and that in abundant
quantities. Heat did not seem to affect it at all, but when I got the
screws out finally, it felt like I dug my way out of Alcatraz with a tea
spoon.
Now, that I think about it, the rod assembly sounds like a better
solution, however the threads didn't seem to chew through the holes in
the tendon at all.
The reason I am replacing it, was a slight discoloration and bleaching
of the orange tendon indicating UV exposure and that it had reached its
retirement age.
florian