myiW Current Conditions and Forecasts Community Forums Buy and Sell Services
 
Hi guest · myAccount · Log in
 SearchSearch   ProfileProfile   Log in to check your private messagesLog in to check your private messages   RegisterRegister 
Anybody using Chinook Pro Flex bases?

 
Post new topic   Reply to topic    iWindsurf Community Forum Index -> Windsurfing Discussion
View previous topic :: View next topic  
Author Message
dhmark



Joined: 04 Sep 2007
Posts: 342

PostPosted: Tue Apr 13, 2021 11:48 am    Post subject: Anybody using Chinook Pro Flex bases? Reply with quote

Several months ago Chinook introduced Pro Flex base which the cup or pin swivels on top of the tendon, thus allowing it to flex easily to 90 degrees for ease of attachment. They say it also reduces wear on the tendon (makes sense). It's a "semi" mechanical u-joint in that it only has one swivel dimension rather than 2. Although the pin/cup can form any angle relative to the base without bending the tendon, it requires the tendon to spin at the base to change some angles, whereas a full mechanical u-joint can form any angle without any spinning.

Conceivably this changes the force required for certain rapid movements of the pin, sometimes spinning (low force), sometimes bending the tendon (higher force), or a combination of both. A full mechanical u-joint or tendon u-joint will require relatively uniform force in any change of angle. Maybe that doesn't make any difference because these forces are trivial relative to the torque applied by the rig. Anybody using this product, and is there any downside at all? Price difference is minimal, improvement in tendon longevity would be a great positive.
Back to top
View user's profile Send private message
killeen_john



Joined: 04 Aug 2006
Posts: 60

PostPosted: Tue Apr 20, 2021 1:34 pm    Post subject: Reply with quote

I picked up a Pro-Flex 2-Bolt Quick Release "Upper" US Base Cup from Windance in December but, haven't had a chance to try it out yet. My primary motivation to buy one verses my current mechanical joint was wanting the safety line in the event of a failure as well as a little shock absorption.

I like using the regular mechanical joint on my formula board but, it has no shock absorption whatsoever and the posts about Chinook mechanical joint failure made me a little nervous about them coming undone.

It also feels like there's a certain rotation angle where the mechanical joint binds up ever so slightly and doesn't rotate freely however, this hasn't caused me any problems yet. The Pro-Flex seems to allow a greater range of motion thanks to the tendon although the jury is still out on the actual benefit here.

Lastly, the Pro-Flex joint assembly is a bit shorter overall than the mechanical joint if that matters any.
Back to top
View user's profile Send private message
us85



Joined: 29 Aug 1999
Posts: 41

PostPosted: Fri Apr 23, 2021 11:35 am    Post subject: Reply with quote

I got single-bolt version just to make adjusting the mast base position easier out on the water (for foiling). All my other bases are 2-bolt, so I'm not really sure how much it helps.
Back to top
View user's profile Send private message
dhmark



Joined: 04 Sep 2007
Posts: 342

PostPosted: Sat Apr 24, 2021 11:08 am    Post subject: Reply with quote

I think its too hard to change mast base position on the water with the sail attached, there's just too much friction or bending (of tendon) necessary with various forces. What you want is ease of connecting sail to board on the water with board and sail lying flat. This would be either mechanical or pro flex u joint and Euro-pin system, US cup would be OK but a little harder. Once sail is off, one-bolt is easiest and fastest, and I have always trusted it.
Back to top
View user's profile Send private message
windyjoe



Joined: 04 Jul 2008
Posts: 8

PostPosted: Sat Apr 24, 2021 4:56 pm    Post subject: New joint Reply with quote

Good for foiling when uphauling not good and really sucks when water starting joint hangs up 90 deg from mechanical joint flips board over drove me nuts till I figured out what was going on foil uphauling great joint centers up and works fine[/u]
Back to top
View user's profile Send private message
wsmtbskate



Joined: 09 Jun 2010
Posts: 109

PostPosted: Sun Apr 25, 2021 7:59 pm    Post subject: Reply with quote

I got a single bolt, europin frankenbase for foiling last year.
works great, no complaints
makes getting the rig on and off much easier when board is in the water,
Back to top
View user's profile Send private message
dhmark



Joined: 04 Sep 2007
Posts: 342

PostPosted: Wed Apr 28, 2021 8:48 am    Post subject: Re: New joint Reply with quote

windyjoe wrote:
Good for foiling when uphauling not good and really sucks when water starting joint hangs up 90 deg from mechanical joint flips board over drove me nuts till I figured out what was going on foil uphauling great joint centers up and works fine[/u]


I got a single-bolt version and tried it for the first time. I'd always used rubber UJ before, had tried regular tendon once before, thought it felt the same. The problem noted above is because when the tendon can't spin (or is hindered from spinning due to friction from other forces), certain motions 90 degrees apart require the tendon to bend and others the mechanical joint flexes. In between the joint will want to flex (path of least resistance) putting some odd force on the board. I didn't notice this happening to me sailing my small board in high winds, wind was catching the board all the time (but maybe due to this issue?). When down in the water I could see that the tendon was straight, UJ bending solely with the mechanical joint, while the whole thing spinning at the base, zero stress on the tendon. This bodes well for longevity of the tendon.

I also noticed that the tendon is much shorter than standard Chinook tendon, and the holes drilled parallel rather than at 90 degree orientation. I asked Chinook about this, they said no problem, the tendon doesn't need full flexion. I'm only sort of satisfied by this answer, would rather have the standard length tendon, maybe this causes the board flipping problem that windyjoe complains about.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    iWindsurf Community Forum Index -> Windsurfing Discussion All times are GMT - 5 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You can attach files in this forum
You can download files in this forum

myiW | Weather | Community | Membership | Support | Log in
like us on facebook
© Copyright 1999-2007 WeatherFlow, Inc Contact Us Ad Marketplace

Powered by phpBB © 2001, 2005 phpBB Group