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Mast Bearing/post
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Author:  pelican [ Tue Mar 27, 2012 6:39 pm ]
Post subject:  Mast Bearing/post

I have two front crossbars for my Hobie 18..... on my older cross bar the mast step/bearing is fully seated to the cross bar eg: no space between it and the bar. On the newer cross bar the step/bearing has about an 1/8th inch gap all the way around, is that normal or should I drill all the rivets out and rebuild that setup?

Author:  jmecky [ Tue Mar 27, 2012 7:57 pm ]
Post subject:  Re: Mast Bearing/post

I have the same exact problem. The newer one is a 4 rivet and the older one is a 2 rivet. And the newer one is up an eighth inch. I have always wondered like you if it was a real big problem.

Author:  srm [ Wed Mar 28, 2012 5:06 am ]
Post subject:  Re: Mast Bearing/post

With the crossbar mounted on the boat, grab the dolphin striker post and try to move it fore and aft. It should be tight. Also you can check the mast step after you've raised the mast and see if it's firmly seated on the mast. If the gap goes away when the mast is raised, then you know the mast step is moving up and down. I'm pretty sure none of my boats have a gap. Certainly not 1/8th inch, that would be a lot. It may be time to re-seat your mast step. Loosen the dolphin striker rod before you put in the new rivets so that the mast step is fully seated. Then re-tension the striker.

sm

Author:  jmecky [ Wed Mar 28, 2012 6:48 am ]
Post subject:  Re: Mast Bearing/post

ss rivets or aluminum.

Author:  wscotterwin [ Wed Mar 28, 2012 7:19 am ]
Post subject:  Re: Mast Bearing/post

Stainless rivets for sure.

I have had replace two of these in the past year on boats I have worked on. Neither fit well as the casting didn't contour well to the cross bar. Also, when I went to put up the mast, I could not place the pin through the castings as the holes didn't line up. I had to drill out the holes to get the pin to fit.

Makes me a little nervous as it looked like I had to remove too much material to get the pin to align between the casting on the mast and the bearing post.

Too many changes to the parts over the years I guess. Make due and make fit I say with an eye on safety.

Author:  srm [ Wed Mar 28, 2012 7:45 am ]
Post subject:  Re: Mast Bearing/post

Yes definitely use stainless rivets.

The mast step pin is notorious for being difficult to insert. It has to do with whether the plastic mast bearing is worn. Sometimes it helps if you take a H16 mast chip, drill a hole in the middle, and install it between the bearing and aluminum mast step. This raises the bearing up so the holes will align.

The other thing you can do is to use a screwdriver in place of the step pin. The screwdriver should have a smaller diameter than the pin (about 3/16") and a handle which makes installing and removing much easier.

sm

Author:  jmecky [ Wed Mar 28, 2012 8:14 am ]
Post subject:  Re: Mast Bearing/post

I had these photos laying around maybe they will help someone.
With this setup the pin fits perfect, and the mast rotator will spin freely.
Image
Image
Image

Author:  dstgean [ Sat Mar 31, 2012 3:05 pm ]
Post subject:  Re: Mast Bearing/post

I jsut got a new to me mast beam with an old style two rivit mast step. I'm having a hard time removing the screw to add a new bearing as show above. Any hints?

Author:  srm [ Sat Mar 31, 2012 4:20 pm ]
Post subject:  Re: Mast Bearing/post

Liquid Wrench.
Impact Driver.
Cut the old bearing off and use vice grips on the screw.

sm

Author:  Harry Murphey [ Sun Apr 01, 2012 9:59 am ]
Post subject:  Re: Mast Bearing/post

Replace the mast base ....

There is a reason why they re-designed the mast base ..... in the "origonal" mast base the mast bearing is held in place by that little machine screw you are having trouble removing ... that's all ... sooooo .... if the screw shears off the mast bearing can "kick-out" .... and that can lead to a brief but extremely exciting event .... also the small surface area of the mast base sometimes "dent" the front crossbar from the concentrated load.

The "new" mast base has a larger footprint to help spread the load out on the front crossbar ... but .... more importantly the mast base is designed so that the dolphin striker post extends completely through the mast base thereby providing a 1/2" SS post for the mast bearing to fit over and hold it in place. Much better ....

And .... you are screwing a SS Machine Screw into a SS Post vs SS Machine Screw into a Aluminum Casting ... similiar metals ... no corrosion/galvantic action .... (that's good too ...)

Author:  dstgean [ Sun Apr 01, 2012 1:25 pm ]
Post subject:  Re: Mast Bearing/post

That'll have to be the direction I take. The one I just tried to remove after liquid wrench and heat sheared the screw head, then after removing the spacer, sheared the bolt flush with the top surface of the old style casting. Sadly, I had one that I used for my other project the Tamanu hulled H18 frankenhobie.

Does the new style come with the SS post for the dolphin striker attached? Any have one they'd be willing to let go? Looks like the p/n 60180011 is 99 bucks at murays, kinda steep for a boat that cost 600 bucks. I still might try to drill out the screw. I hate when projects snowball like this...

Author:  Harry Murphey [ Sun Apr 01, 2012 4:26 pm ]
Post subject:  Re: Mast Bearing/post

Just look at the pic's posted on this thread by Mr "jmecky" ...

The first pic shows the top of the dolphin striker w/ the screw and his solution for a "bearing surface" under the mast bearing that allows it to "spin" freely ... the second pic shows the mast bearing in place having slide down on top of the post ....

You'll need a "new" mast base AND also the associated "new" Dolphin Striker post ....

... try Jeremy at Surf City .... (831) 475-7245 ... he may have something "used" laying around his shop ...

Author:  dstgean [ Mon Apr 02, 2012 5:29 am ]
Post subject:  Re: Mast Bearing/post

Harry Murphey wrote:
Just look at the pic's posted on this thread by Mr "jmecky" ...

The first pic shows the top of the dolphin striker w/ the screw and his solution for a "bearing surface" under the mast bearing that allows it to "spin" freely ... the second pic shows the mast bearing in place having slide down on top of the post ....

You'll need a "new" mast base AND also the associated "new" Dolphin Striker post ....

... try Jeremy at Surf City .... (831) 475-7245 ... he may have something "used" laying around his shop ...


That's what I thought... & the mast beam and what not is actually from Jeremy. Good guy to deal with imho.

Author:  srm [ Mon Apr 02, 2012 7:06 am ]
Post subject:  Re: Mast Bearing/post

I'm wondering if anyone has actually had the mast base kick out due to a mast bearing failure on the old style mast step. The reason I'm wondering if this could actually happen is because the mast base hinge actually overlaps not only the plastic mast bearing but also the aluminum portion of the mast step. So while I could see the mast bearing screw shearing off, it looks to me that the base of the mast would still be captured by the step.
No doubt a failure of any part of the mast base would put a damper on your day of sailing, but I'm not sure whether it would cause a catastrophic failure - i.e., dismasting. Certainly the new style mast base is an improvement in many ways.

sm

Author:  MBounds [ Mon Apr 02, 2012 8:54 am ]
Post subject:  Re: Mast Bearing/post

Harry Murphey wrote:
... try Jeremy at Surf City .... (831) 475-7245 ... he may have something "used" laying around his shop ...


FYI, Jeremy sold the business a few months ago.

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