Hi Fellow windsurfers.

I have heard about universal joint failures and the resulting damage it can cause. Some of the failures are caused by the failure of the rubber tendon or bodge and some are caused by pin failure as well (in the cases where the pin has not been integrally cast to the tendon retainer body).
Ive seen that Cardan bases are also available and was wondering if these would be a more reliable option compared to Bodge & tendon bases as they do not use any rubber to act as the articulated joint between board and mast.

Im therefore wondering what experience people have had with Cardan Bases. I have not seen too many people use them so I assume they have major drawbacks.

Could those that have used them explain the type of sailing conditions they have tried them on..ie speed, slalom, wave, freeride etc.. flat water, clean waves, dis-arrayed chop etc.

Im a lakes free-ride windsurfer, and the area I sail in does get very choppy at times. Ive heard that these UJ's transmit significantly More "shock" loads through the rig than the Bodge & tendon Bases making very uncomfortable sailing. Is that correct?

Never heard of Cardon. Got a link?

I supppose Discus is refering to the mechanical base



Which in french would be called a CARDAN (shaft)

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seanhogan said..
I supppose Discus is refering to the mechanical base



Which in french would be called a CARDAN ( "Universal Joint" )

Yes, Seanhogan, that's the base I'm referring to. Thanks

I thought mechanical ujs were no good because they can lock up when the pins line up in some circumstances and break easily.

i have used US mast bases of various shapes

the "mechanical base" is a favourite for large sails on wide boards
the mast extension is attached to the mast base on the board with all parts lying flat on the water
have NEVER had any lock-up, loose screws (besides in me head) or other with these bases
joewindsurfer.blogspot.com/2013/11/windsurf-mast-bases-and-extensions.html
i also like the two bolt mast base plate attachment on the board

Joe Windsurf, Thanks for your response!

Why specifically : "favorite for large sails on wide boards"? Is it unsatisfactory for say a 120L free-ride board and 6.4m sail?
Do you experience any more shock load transmission issues than you would from the Bodge and tendon types ?

I would suggest there are reasons 90% of people use a rubber UJ of either variety, after 40yrs of all kinds of designs they prevail.
So I do the same....

Thanks Mark.
Very persuasive argument, but are we missing a better UJ because we are all "following" each other?
This is why I'm asking feedback from those that have used this type UJ.

I think that Joe is making the point that a heavy large sail and a wide board can make for a difficult time getting the pin and extension aligned, especially if you add waves into the equation. The advantage with an mechanical is that you are able to leave the board flat on the water while attaching the base to it as the base can be bent 90 degrees, without the resistance that a rubber uni has. I had a mechanical F2 uni that did make this job easier.
Don't recall it being noticeably harsher, and never had it lock up at all.

Thanks Ballast. That's clearer now.
Thanks for the feedback on the ride quality and no lock-up!!!

Sand will make it lockup and like Shifu said there will be one orientation that stresses it more I guess.

Discus I don't think we are all just following as there was mechanical uni's from the early 1980's and they just went away. Later versions are the same thing with minor materials refinement and still have not caught on.

Thanks again Mark,

Two people that have used them, have said they have never had them lockup.

Im curious to see if anyone comes forward to say that it has happened to them.

Hi Discus. I used a Cardan-type uni joint years ago. It was a Chinook, with a 2 bolt base as Joe pictured.

The issue I had with it was that it was very unforgiving, and had no shock-absorbing properties. (Of course, everybody knows you should use a Cardan joint in a drive shaft, not in the suspension- but that's beside the point). It was OK for slalom sailing, where you weren't usually getting air, but if you ever landed a jump, even a small one, the all shock would be transmitted from board to rig, and vice-versa, usually then reverberating through your body. I can understand how they might be OK with big sails and big boards, where you are probably in a lighter wind, flatter water state. But forget about it if there's any bumping or jumping involved.

They seemed to fall out of favour. Most of my sailing was in choppy conditions, so I never bought another one. I do remember them occasionally locking-up, more so when the joint got a bit older, and if any friction started to develop, the joint wasn't able to twist in some configurations for the true universal rotation to occur. It only ever happened when you wiped-out, and then if th ejoint locked-up, your board would just tip over. It was never a problem when sailing though, as any torque going through the joint was much greater than any friction, so it would twist as required.

Come to think of it, when it did lock-up, it was probably more because the base didn't rotate in the base plate properly, i.e. about the axis perpendicular to the deck of the board. Or put another way, the pin and collar that inserted into the bore in Joe's photo didn't rotate freely, probably because of sand or roughnesss between the two bearing surfaces. I don't ever remember either of the other two pivots seizing.

Mikey, Many Thanks Pal!

Is it possible from your experience that if when it locked up you were still on the board and you dropped the sail (from a gust) it could rip the mast slide out of the board?

What UJ are you using these days?

If there has been any issues with those universal joints that were mentioned locking up, I would stay away from them. Even if it's only 1 in a million, not worth the risk. It could have been a manufacturing defect, but still. Maybe consider the rubber universal joint, it will never lock up, and they last for a long time. Very unlikely the rubber will break anytime soon of ownership. Peace of mind is really what ya want when you're on the water.

P.S.
If anyone has had a rubber universal joint break on them, would love to hear from you.

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MikeyS said...
..., everybody knows you should use a Cardan joint in a drive shaft, not in the suspension- but that's beside the point).

I'm not disagreeing, just a "well actually"...[;-)]

I think that has more to do with it not being able to rotate at constant velocity, particularly as the angle changes. Drive shaft would use 2 at fixed angles.

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Magic Ride said..
If there has been any issues with those universal joints that were mentioned locking up, I would stay away from them. Even if it's only 1 in a million, not worth the risk. It could have been a manufacturing defect, but still. Maybe consider the rubber universal joint, it will never lock up, and they last for a long time. Very unlikely the rubber will break anytime soon of ownership. Peace of mind is really what ya want when you're on the water.

P.S.
If anyone has had a rubber universal joint break on them, would love to hear from you.

Have had quite a few breakages of rubber uni's. Including some that have crumbled into pieces when I have given them a bend to test their condition before using them.

Only two on the water that I can recall. One memorable one was one I was gifted by a good mate who had converted to RDM.

Hit the water on a particularly breezey afternoon after rushing down and rigging at a spot close to home. Hit the again water, literally after about 200m as uni snapped and board and rig parted ways. Board decided to head back to rock retaining wall lined shore without me. Fortunately it was only waist deep and I was able to just grab the back of the board after a long chase.

Strangely enough now I do a visual check of my uni's and use only ones that have a second method of retaining connection if broken.

Also, all the original wally boards I have had ( four I think) , have had a mechanical type uni. All of these were still functioning okay after 35 plus years. Not sure any type of rubber uni of that age would still be functioning.

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Discus said..
Mikey, Many Thanks Pal!

Is it possible from your experience that if when it locked up you were still on the board and you dropped the sail (from a gust) it could rip the mast slide out of the board?

What UJ are you using these days?

No, it never locked up like that. It only ever happened after I'd dropped the sail, was probably in or on my way to being in the water, and then locked and rolled the board. No doubt that if and when it locked, it put a fair bit of force on the board around the mast track, but with the Chinook two bolt base, it never slipped. I did go to two bolt bases after having slipping problems with the old Tyronsea (just dated myself there) single bolt bases. Never ever had a problem with the Chinooks- rock solid. Actually, as Sav911 alluded to (knowingly or not), it was only really at risk of locking up if the angle between the axis of the pin and the axis rotation at the base plate was great, i.e. as the pin angle approached 90 degrees to the plane of the board. Or in other words, when you've dropped the sail and it's just about to hit the board.

These days I've gone back to tendons (North), but liked using Boge rubber unis for quite a while. Actually the North tendons are quite stiff, and sometimes the board will roll in the same way as when the Cardan uni locked. No big deal really- just means you have to flip the board back then waterstart.

"Boge" is a strange word. Does anyone know where it comes from? Does anyone know how to pronounce it?

Boge is a German rubber and plastics manufacturer. They do a lot of automotive and vehicular suspension components.

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Magic Ride said..

If anyone has had a rubber universal joint break on them, would love to hear from you.

They break from overuse. The rubber fatigues and cracks from the inside - i.e. you can't see the cracks until they fail. I've had 1 break this way in early 2014. I now replace them every 1,500kms.

bic techno use the mechanical base, they seems to outlast rubber bases and its the largest windsurf class so they are well proven for reliability

I think both systems have their merits and it doesn't really matter what type.you use.

A modest discussion here on uni and base choices covering all three:

Well then Lads,

Im starting to think that this is a case of "you cant have your cake and eat it too!".

On one hand, Cardan UJ's do work OK (especially the Chinook design) but its main disadvantage is shock load transmission (bad for the knees and other body joints), but its main advantage is reliability.

On the other hand, the rubber Ujs, have far better shock absorption, but upon failure may wreck your board, injure you , and you may end-up stranded somewhere, and you cant tell pending failure because it deteriorates from inside -out!


Great!

I have not broken a Chinook tendon in the last 15,000kms of sailing. I sail in very rough water 3-4,000 km per year. I have two bases, use them alternately and change the tendons each year. I also change the keeper lines which the Chinook design permits. Preventative maintenance is the key.

Wow that's impressive Shifu, however, In one of the forum discussions, someone had numerous consecutive failures of the tendons because of a "bad batch" (so regular changing doesn't necessarily ensure reliability). I guess the keeper lines are the safe-guard, but are they short enough to stop the sharp UJ frame from ripping into the board?

It was this that I was alluding to, which has nothing to do with windsurfing or shock absorption, just why they don't use these joints in the wheels of your car.