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Mast bob alternative
http://www.hobie.com/au/en/forums/viewtopic.php?f=14&t=38388
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Author:  pyroboy08 [ Fri Sep 09, 2011 5:36 pm ]
Post subject:  Mast bob alternative

Has anyone experimented with an alternative to buying a hobie mast bob? I could easily slap together something, but I want something that won't look like I slapped it together. I am 16, no real job and therefore tight on cash. I would rather spend that money on a trap system. Thanks.

Author:  ronholm [ Fri Sep 09, 2011 7:11 pm ]
Post subject:  Re: Mast bob alternative

seal the mast you have so it does not leak.. you won't need a bob...

SS rivets are not that expensive

:P

Author:  jsloan999 [ Mon Sep 12, 2011 12:17 pm ]
Post subject:  Re: Mast bob alternative

In the past I have seen a tether ball tied to the top of the mast. Did not look that great, but worked.

To test the mast for leaks - Put the mast in a pool or lake and look for bubbles.
If it leaks from the top or bottom of the mast, one of the mast end foam plugs (one at each end) will need to be sealed. You would need to remove the mast base or mast head. I would think filling the area with expanding foam would seal it.
If it leaks around any rivets, you can seal with silicone or better yet replace the rivet using ss rivet w/ a casing.

Author:  pyroboy08 [ Mon Sep 12, 2011 2:41 pm ]
Post subject:  Re: Mast bob alternative

Thanks guys, I've yet to capsize my Hobie but I was trying to be preventive. I was not aware that a sealed mast is buoyant. From looking at it, I would be willing to bet that my mast would leak.

Author:  ronholm [ Tue Sep 13, 2011 12:19 pm ]
Post subject:  Re: Mast bob alternative

And if your mast leaks.. and you put bob up there to fix it.. the mast is still going to leak... making the boat very hard to right...

Give a Hobie dealer a ring.. less than 25 bucks in rivets,sleeves and some quality silicon and you will be good to go...

Author:  culpyy [ Tue Sep 13, 2011 2:44 pm ]
Post subject:  Re: Mast bob alternative

Question: Besides turtling after capsizing and the fun of getting your hobie right side up again, how does determine if the mast is properly sealed? I would prefer to know before I go. Thanks for the help!

Author:  56kz2slow [ Tue Sep 13, 2011 2:45 pm ]
Post subject:  Re: Mast bob alternative

Put your mast in a pool or a lake and watch for bubbles.

Author:  culpyy [ Tue Sep 13, 2011 2:46 pm ]
Post subject:  Re: Mast bob alternative

Thanks John. I should not be so hasty in the question asking....I'll try the lake test.

Author:  culpyy [ Tue Sep 13, 2011 2:46 pm ]
Post subject:  Re: Mast bob alternative

Thanks 56kz2slow!

Author:  fastcat [ Tue Sep 13, 2011 6:13 pm ]
Post subject:  Re: Mast bob alternative

The lake test may or may not answer your question. If you put the mast horizontally in one foot underwater the pressure is only 1.03 atm, but at 26 ft deep the pressure is 1.79 atm. Another test is to intentionally turtle the boat and let it stay that way 10 minutes (you may want back-up for the righting in-case you have a substantial leak). Right the boat, get it back on land, drop the mast and shake it. If there is sloshing, you got a leak. That is how I found I had a leak in my H16 mast. Then to find where the leak was I did the following. On my mast I had installed a sail guide to help feed the main sail up the slot. I removed the guide (2 screws), then replaced one of the screws and pressurized the mast with a bicycle pump throught the other screw's hole. The leak turned out to be at 3 tang rivets. I drilled out the 3 leakers, installed new casings and rivets. Presto - no leaks. Easy peezy. :wink:

Author:  culpyy [ Tue Sep 13, 2011 11:16 pm ]
Post subject:  Re: Mast bob alternative

Beautiful! Certainly the deeper you go, the greater the force of water is to violate the mast air space. Makes sense. If your leak is small, like I would think a few leaky rivets would be, would capsizing always lead to turtling? With the flow of water being so small and the mast located just under the surface even a "leaky" (albeit small) mast would be hard to diagnose if you righted the boat quickly after capsizing. I guess I could place the mast in a lake, remove one of the screws that secure a Cleat and pressurize as you described and look for bubbles. What'd ya think?

Didn't mean to hijack this thread. New to the forum thing. Sorry! Hope the info is helpful anyway.

Author:  fastcat [ Thu Sep 15, 2011 1:01 pm ]
Post subject:  Re: Mast bob alternative

culpyy - no a capsize does not always lead to a turtle, but in my experence, it usually does. That mainly is because I pretty much only flip when going fast on a reach or after a high wind jibe. In each case I pitchpole and the boat is turtled within seconds (I do not use a BoB). In some cases I prefer to turtle. I mostly solo and turtled the boat is very stable so I have time to get my fecal matter together, release all sheets, release the traveler and make sure the hiking stick is not fouled. Then I can pick the leeward hull to stand on and unturtle/right the boat. The wind pressure on the tramp helps get the boat on it's side and many times it continues to a full righting.
As for testing, that is why I suggested a 10 minute wait while turtled. That should be plenty of time for leak to allow enough water in to do the slosh test. Good luck, I'm off to the ramp to launch - the winds are 10 - 20 today. 8)

Author:  culpyy [ Thu Sep 15, 2011 1:18 pm ]
Post subject:  Re: Mast bob alternative

Thanks again for the info! Enjoy that great wind!

Author:  jsloan999 [ Thu Oct 27, 2011 1:09 pm ]
Post subject:  Re: Mast bob alternative

I had heard of attaching fenders. I took this pick in France last month. I am trying to rember the model of Hobie cat - Avalanch maybe?

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