Go Back   Starboard Forums > Ask Our Team

Reply
 
Thread Tools Display Modes
Old 21st February 2007, 02:11 AM   #11
Ola_H
TEAM
 
Join Date: Aug 2006
Posts: 1,191
Default RE: Some Streamlined related....

Geo: Here is an image of the "new" North design:

http://www.surfzone.se/forum/attachment.php?attachmentid=10042&stc=1&thumb=1&d= 1135038221

(remove the linebreak after "?" when copying to your browser)

Just a simple one piece solution. I suppose its still machined but theoretically you could forge it too. Either way, I think it would still easily outlast the mast foot itself.
Ola_H is offline   Reply With Quote
Old 21st February 2007, 02:17 AM   #12
Klint
Member
 
Join Date: Aug 2006
Posts: 66
Default RE: Some Streamlined related....

Thanks for advices!

When assembeling the mastfot agian, should I use something on the screws to make them stick? Roger mentioned the product Never-Seize, but this sounds like a lubricant to me which implies the opposite effect to for instance Loc-tite. Lots of questions from my side, just don't want to be way out with a mastfot failure.

/ Andy
Klint is offline   Reply With Quote
Old 21st February 2007, 03:21 AM   #13
Jean-Marc
TEAM
 
Join Date: Aug 2006
Posts: 1,359
Default RE: Some Streamlined related....

Ola,

http://www.surfzone.se/forum/attachment.php?attachmentid=10042&d=1135038221

I agree a one-piece-single-metal machinated upper cup-Euro pin part will be better than a two-metallic-three-pieces assembly. Forging or soldering is bad because failure usually occurs precisely at the junction between 2 parts...

Klint,

I don't use any Locklite or Never-Seize stuff. Just strong tightening of the 2 screws on each interconnecting axis.

I just make sure all the screws on my gear are tight before each session (footstraps, fin, boom head and mast base/tendon/pin assembly).

Cheers !

JM
Jean-Marc is offline   Reply With Quote
Old 21st February 2007, 03:43 AM   #14
Ola_H
TEAM
 
Join Date: Aug 2006
Posts: 1,191
Default RE: Some Streamlined related....

JM: OK, I got the wrong english word then. Whats it called when you kind of "cold hammer" it to shape?

(And how did you prevent the link from breaking?)
Ola_H is offline   Reply With Quote
Old 21st February 2007, 03:53 AM   #15
steveC
Member
 
Join Date: Aug 2006
Posts: 639
Default RE: Some Streamlined related....

Thanks Ola H. for including the photo of the North universal, as I've never seen one before. I'm presuming that the SS component is machined from a single piece of SS. Although conceptually very similar to Chinook's variant, the solution is a bit different (the tethered plastic component). Also, the plastic component assembly on North's universal does hide the exact constitutes of the bottom assembly. Maybe it remains more traditional in nature integrating metal and molded plastic components together as an assembly.

In Chinook's approach, it's my understanding that they offer a single threaded screw (screw shaft is an inherent part of the machined parent SS component that attaches to the base of the tendon) as a design alternative to the pin type of attachment that I described in my prior post. Does North offer similar variants?

For geo,

While I wouldn't disagree with you in any way concerning Euro Pin designs if different SS components are assembled together to create a universal assembly, I'm inclined to think that one piece machined SS components are superior in design, and as a result, they greatly limit the opportunity for failure.

However, if the machined components do not include the proper stabilization and hardness processing, and particularly if inadequate radii at points of transition and stress are introduced, there is a much higher risk of stress propagation and an untimely failure. Ola H's proposed ultimate solution using a forged shape instead of machining from bar stock would clearly be the optimum way to go. Nonetheless, from what I can discern in Chinook offering, it appears that they have done an adequate job with radii on machined SS parts.

The thing that really disappoints me is that Chinook's pin configuration doesn't necessarily work between different brands (ie: Streamline mastbases). One wonders whether that variance was designed in on purpose.

steveC is offline   Reply With Quote
Old 21st February 2007, 12:05 PM   #16
Roger
Dream Team - School Guru
 
Join Date: Aug 2006
Posts: 2,110
Default RE: Some Streamlined related....

Hi Klint,
Yes, the Never-Seize is a lubricant and prevents galvanic corrosion.
I'm not sure if there's "lock-tite" on the little screws that hold the cross pin in a genuine Streamlined tendon joint or not, but I do know that I often find a little corrosion on the threads of the small screw, and there is often evidencs of a little galvanic corrosion between the stainless steel crosspin and the aluminum alloy of the cup the tendon seats in.
So, the Never-Seize is there to prevent all types of corrosion.
The way that Dave Dominy has set up the cross pins in the genuine Streamlined tendon bases, the cross pin does all the work, and has all the shear strength, the two small screws are just "retianers" to ensure that the pin does not fall out or shift off center.
So, lubricant is better here, as it makes the screws easy to get out when you want to inspect them next year.
Just tighten the 2 small screws nice and snug, and they will do their job of holding the much stronger cross pin in place, but since there is no stress or load on the screws they also will not fall out.
That's why it's important to get some really long screws to use when tapping the cross pin out. These screws should be screwed all the way in until they bottom out in the threads in the cross pin, so you don't damage or distort the ends of the cross pin.
Hope this helps,
Roger is offline   Reply With Quote
Old 21st February 2007, 01:55 PM   #17
geo
Member
 
Join Date: Aug 2006
Posts: 327
Default RE: Some Streamlined related....

Quote:
Ola_H wrote:
Geo: Here is an image of the "new" North design:

http://www.surfzone.se/forum/attachment.php?attachmentid=10042&stc=1&thumb=1&d= 1135038221

(remove the linebreak after "?" when copying to your browser)

Just a simple one piece solution. I suppose its still machined but theoretically you could forge it too. Either way, I think it would still easily outlast the mast foot itself.
Ola,

the design looks tough, by sure a great move from the usual two part with threaded pin that I see around. The threads were the weak point there.
By sure, this will be way safer. In this case, as any mechanical engineer will tell you, the weak point is where diameter abruptly changes from the "pin" part to the wider "tendon cup" part. Stress will concentrate there and, in case there is surface uneveness of any kind (scratches, corrosion, machining defects) fatigue will have its way. The bevel on top of the "cup" section will help for this, but not avoid it. Only, with such a thick part, it will take quite a lot of time for a crack to develope. I still can't see any reason to prefer this over a two-pin cup that simply is not subject to such issues. And that, I guess, is times cheaper and lighter.

SteveC,

that's the point: everything can be done, but...
Stabilization, hardening, forging, dealing with tapering radius and bevels... why? Why mess with expensive, heavy, complicated mechanical engineering to produce parts that have the habit to cleverly hide their integrity status, when you can have a simple plastic part that simply can not break (unless maybe it's so worn out that shows very clearly its state and you would never dare to use use it, and probably nevertheless it would never break even that way)?

These new parts seem OK, I guess the Chinook one is OK too, but a) in the meantime probably thousands have had to do the swim in, and 2) anyhow a simple inexpensive plastic cup will do the same job or better and be lighter and inexpensive.
geo is offline   Reply With Quote
Old 24th February 2007, 05:05 PM   #18
Klint
Member
 
Join Date: Aug 2006
Posts: 66
Default RE: Some Streamlined related....

I did the mast foot check on my Streamlined and was quite surprised when noticing a clearly visible crack running all the way down the lower tendon retaining pin. The pin was also bent into a slight banana shape. Will have this replaced, just a matter of time before the pin would snap completely. No fun, especially if you go for longer cruises as I normally do. Suppose there’s an aftermarket for theses spare parts. Another weak part on the Streamlined is the screws that holds the pin which are out of rather soft steel and easy to ruin when undoing.

I also realized in case of a Streamlined mastfoot failure, the rigg would dance around on my Starboard wooden deck and eventually ruin it. This due to the single safety marlow line which is quite long. Think a better solution would be the one Chinook applies, with two safteylines which limits movement in case of a breakage.

If I’m now ordering a Chinook mastfoot with US cup, will this be a good match with my Streamlined extensions? SteveC implied that the Streamlined pin system will not work with Chinook. Hope this doesn't go for the US system. And finally, would it be possible to retrofit a Chinook mastbase with a Streamlined joint?

All the best,

// Andy
Klint is offline   Reply With Quote
Old 24th February 2007, 10:52 PM   #19
Ola_H
TEAM
 
Join Date: Aug 2006
Posts: 1,191
Default RE: Some Streamlined related....

Actually, there are two versions of US cup too, some are just a tad larger diameter (I think this applies to fx NP) but the difference is not bigger than some light tinkering can take care of. If I recall, Streamlined and Chinook are perfectly compatible though.
Ola_H is offline   Reply With Quote
Old 25th February 2007, 12:17 AM   #20
steveC
Member
 
Join Date: Aug 2006
Posts: 639
Default RE: Some Streamlined related....

Hi Andy,

I must emphasize that the incompatibility between the Streamline mastbase and the Chinook universal was limited to the Euro Pin configuration, and the source of the problem was Chinook's version of the Euro Pin. Also, just for the record, my Chinook Euro Pin universal was an early model that I bought when they first released the SS design. More than a year and a half that have passed since I bought the universal, and it could be possible that Chinook has corrected the configuration of their pin, so it would be prudent to check before you buy.

I doubt very seriously that there would be a problem integrating the two pin cup configuration components between Streamline and Chinook. Although I don't own a Streamline mastbase, I know that both the Streamline and Chinook two pin cup universals work well in my older Fiberspar SDM configuration mastbases, and also in a Gulftech skinny mastbase that I have.
steveC is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +7. The time now is 05:13 AM.