Hobie Forums

Mast Support Fail
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Author:  fusioneng [ Mon May 13, 2013 7:49 am ]
Post subject:  Re: Mast Support Fail

Has anyone tried shoving a plastic plug into the 1/2 inch dia hole in the bottom of the mast to help shim it up off the bottom (if needed). The mast spins easiest if the contact point on the bottom is as small as possible. (maybe half a plastic ball jammed in there so it spins on a point (like a compass needle)) , or maybe just the head of a stainless flathead screw sawed off and glued into the bottom of the hole with epoxy, (you can call it a jeweled movement like in watches if you use a ruby LOL), (NOTE: you might need to put brakes on your furler cause it spins so fast (just kidding)) just a thought

I had a related problem with my mast where when stepping the mast one time, I shoved the mast into the mast plate (where the bearings are) and accidentally bent it upwards, after which it rubbed when furling. Once I noticed the wear, I bent the aluminum brace back down to it's proper position, and everything has worked fine since.

On several occasions while transporting the mast around I have bumped into things and the collar on the mast has slipped (it doesn't take much to move it, just a slight bump). On more that one occasion this was the root cause of all my problems (slipped collar).

I agree that measuring everything is the best way to find out what is really going on. The exact precise dimension is probably not important, it's the relative comparison dimension that counts (1-2mm difference is ideal)

My 2 cents

Author:  aussieonyak [ Mon May 13, 2013 11:05 pm ]
Post subject:  Re: Mast Support Fail

OK many thanks Slaughter for the detailed explanation, and again Tom for your help - I will get the tape measure out and determine the extent of the issue so I can decide what I need to do to fix. Sounds like the solution either way is easy enough once I figure it out.

Author:  Tom Kirkman [ Tue May 14, 2013 5:57 am ]
Post subject:  Re: Mast Support Fail

There is some side to side play in the mast base. I had thought taking this up would improve things but it actually makes the sail harder to furl and/or extend with any pressure on it at all. I suspect the fairly loose tolerances are there for a purpose.

You need at least 2mm between the bottom of the furling drum and the top of the mast support plate as when under power the mast will lean far enough, and there is enough play in the system there, to allow these pieces to come into contact on whatever the leeward side happens to be.

If the drum is slipping on the mast, then it's not well adhered. This means you're in a good position to remove it and re-adhere it in the proper location.

Author:  fusioneng [ Tue May 14, 2013 7:17 am ]
Post subject:  Re: Mast Support Fail

I'm on my third TI now, and all three had the exact same issue with the loose mast collars. If you bump it at all when walking (it doesn't take much) the collar slides up and down. None have ever rotated, and they are easily bumped back. If I had that problem on 3 out of 3 masts, (all came from the factory that way) it's likely others just might have the same issue, that's the only reason I mentioned it. A quick measurement will confirm if it has slipped, and hopefully save someone all the work of trying to adjust all the wrong things. Now whenever I get a new TI one of the first things I do is confirm and mark the correct position for the mast collar, so I can always bump it back to the correct position.

That was my only point.


Author:  Tom Kirkman [ Tue May 14, 2013 8:39 am ]
Post subject:  Re: Mast Support Fail

Right, I was just saying that if anyone does have a drum that moves when bumped, the adhesive has let go and you might as well take the measurements and re-adhere the drum in the proper location. Done properly, it will never move on you again and since the drum is already "loose" it won't be that hard to get it off.

Author:  fusioneng [ Tue May 14, 2013 10:21 am ]
Post subject:  Re: Mast Support Fail

I agree with you Tom that if found the problem should be corrected (re-glued, as always your suggestions always work the best), I was just trying to point out the possible problem of loose mast collars may be more rampant than what we have been led to believe (based on my 3 out of 3 bad ones).
My observation of the epoxy type used in their production is that it might be possible that they are using a quick set type general purpose type epoxy in production (only Hobie knows for sure what they use), something like ( http://www.loctiteproducts.com/p/epxy_q ... ck-Set.htm ). If you look at most of those quick set grades, most are not typically advised for high moisture areas ( water can and will wick in under that collar and just sit in there), unless it's of course a special marine grade epoxy.
I'm just trying to point out the obvious (based on my 2010, 2011, and 2012 loose mast collars from the factory, and the tell tale white appearance of the failed epoxy (usually means it's been moisture attacked). Knowing Hobie, they will read this and quietly look into it and apply corrective measures if needed (they always do).
I'm only saying anything because I hate to see all these people trying some of these odd fixes and adjustments, to try and correct what might turn out to be a manufacturing oversight in the Hobie factory. Then again this could be all about nothing.

Author:  Slaughter [ Tue May 14, 2013 8:08 pm ]
Post subject:  Re: Mast Support Fail

I wish mine was as easy to remove Bob. If so I would have relocated it and re-glued.

Could I just say that the there is confusion amongst us as to what a mast support plate is. I would say that if the correct Hobie teminology for the plate that Aussie has worn in his photo is the mast support plate, then it needs to be renamed. I thought that plate was called the mast receiver which makes sense. With it's balls, it may provide lateral restraint to the mast but thats about it, it doesn't support anything. The mast support plate in my mind is the stainless steel plate at the base of the mast, which supports the mast through its pin.

Author:  tonystott [ Tue May 14, 2013 10:52 pm ]
Post subject:  Re: Mast Support Fail

Slaughter, the part you are correctly referring to is the #29530001 Mast Bearing Plate, and there is one above and one below the crossbar, and they hold the 24 delrin bearings in place . There is a part #79511101 Mast base which is only shown on the TI parts pages, but I assume it is the same in both Islands. The #79514101 Mast Receiver is the long vertical tube which is bolted to the deck under the mast bearing plates (same on both Islands post '08)

So I think the confusion is not of Hobie's making... The part getting rubbed is the (plastic) Mast Bearing Plate, and the part that the mast rests on at the bottom of the hole is the Base Plate, which I believe is what you are pointing out! :D .

Author:  Slaughter [ Tue May 14, 2013 11:44 pm ]
Post subject:  Re: Mast Support Fail

Thanks mate. Now if Eddie McGuire ever asks those questions we will be set for a Million.

So there is no such thing as a mast support plate ? Good to know ! While you're there Tony, could you point me in the right direction as to where all these part no's are listed !

Author:  stringy [ Tue May 14, 2013 11:47 pm ]
Post subject:  Re: Mast Support Fail

Thanks for clearing that up Tony! :)

Author:  tonystott [ Wed May 15, 2013 7:31 am ]
Post subject:  Re: Mast Support Fail

Slaughter, I found the information on the Hobie website! D'OH!
http://cdn1.hobiecat.com/digital_assets ... 130424.pdf

Author:  aussieonyak [ Tue May 21, 2013 6:49 pm ]
Post subject:  Re: Mast Support Fail

I just got a response back from my Hobie dealer. They said they have talked to Hobie and they said "we can adjust the strut tension on the turnbuckles that are located on the inside of the kayak -- this should do the trick". So it looks like the turnbuckles will be the first attempt to fix it. I will be getting the Hobie Dealer to make the adjustment. Will let you all know what the result is.

The measurements on here have thrown me as mine look different to the others on here - when I measured my TI furling drum I get 11 7/32" or 285mm. The distance from the bottom of the mast receiver to the top of the roller bearing plate is 11.5" or 292mm. From the top of the pin to the top of the roller bearing plate is 10 5/8" or 270mm and the depth of the bore in the mast is 18 mm. So I think that means I need a 5mm adjustment - and if the solution is to use a plug it would need to be 5mm thick to give me a 2mm clearnace would that be right?

Author:  Tom Kirkman [ Tue May 21, 2013 7:11 pm ]
Post subject:  Re: Mast Support Fail

Even the cheapest epoxy formulations aren't usually to blame for such failures - the cause is improper surface preparation.


In a mass production setting it's easy to neglect this all important work in preparing surfaces for adhesion.

Author:  aussieonyak [ Wed May 22, 2013 12:33 pm ]
Post subject:  Re: Mast Support Fail

Tom Kirkman wrote:
I was on the phone with Dan Ketterman yesterday about some things pertaining to the TriFoiler. Somehow we got on the subject of the Island kayaks and discussing the V-Truss he said it wasn't meant to be used for raising or lowering the mast support structure. I mentioned that I set my V-Truss by bringing everything into contact, and then giving the turnbuckles 1/2 turn (expand) to snug everything in place and he said, "That sounds about right."

Using the V-Truss to push the hull up or pull it down only puts undue stress on the hull that can lead to problems. The V-Truss isn't there to serve that purpose.

After thinking about what Tom had said here I asked the Hobie dealer to double check with Hobie engineers the wisdom of adjusting using turnbuckles. They then recommended using small washers under the pin that holds the mast inside the mast receiver to raise it up just a little bit so that is what the dealer will do.
I'll let you know if that corrects the problem.

Author:  fusioneng [ Wed May 22, 2013 1:25 pm ]
Post subject:  Re: Mast Support Fail

Hey I was looking inside my mast hole cleaning it the other night, and noticed that there has never been contact with the plate at the bottom of the mast pocket, and the bottom of the mast, both are like new with no scratches of any kind, yet the bottom of the mast pocket was full of sand (why I was cleaning it out with the wet vac).
What this tells me is that the mast bottoms out on the top of that pin inside the mast pocket, and spins on that pin.

I am not having problems with my mast, the spacing seems to be correct, I did measure the distance from the mast plate to the top of the plate with the delrin balls and it measured 11.4" inches. The measurement from the back of the mast to the collar underside was 11.5", and as mentioned above the end of the mast has never touched the bottom of the plate (no scratches).

I guess what I'm trying to suggest is if you are planning to add spacers, add them to the hole in the bottom of the mast, they will likely work better.

Just my observations

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