Hey guys,
I noticed that the mast base on my H18 was creaking and moaning a fair amount so I pulled the mast base to inspect and found that the crossbar was deformed and there was a crack going from one of the mounting rivets to the hole for the dolphin striker. Earlier this year 2 of the other guys in fleet2 had to replace their xbar for the same reason. Couple questions:
1) Our local H18 expert recommends using the 2 rivet mast base since the rivet holes seem to lead to these cracks, but I also see Matt Miller from Hobie and others recommend moving to the 4 hole mast base
2) how do you tension the mast base? Is there a formula?
For the record, the current mast base is a 4 hole and the replacement xbar is a 2 hole. So obviously I have the parts to do this either way, I just want to figure out which way is better.
Any other tips/tricks/recommendations for how to fix this mast base?
Thanks,
Eric
Hobie 18 mast base
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Posted: Jun 13, 2013 - 10:39 AM
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Posted: Jun 13, 2013 - 11:37 AM
From what I understand, the deformation and cracking comes from the mast base rivets stretching (loosening) from dolphin striker's upward force and allowing the base to work up and down. If the riveted connection remains tight, the cross bar should not deform or crack. The 4 rivet base will resist deforming the rivets better than the 2 rivet model, as there are 2 more rivets to resist the dolphin striker's upward load.
Edited by presto13031 on Jun 13, 2013 - 12:38 PM.
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Jeff
Houston TX
1986 Hobie 18 Sail# 13031
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Posted: Jun 13, 2013 - 05:29 PM
I used larger rivets in my 2 hole base when it got loose. Need a big rivet tool but it is really solid. I agree the cracks develop after the base gets loose.
Edited by pknapp66 on Jun 13, 2013 - 05:30 PM.
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Pete Knapp
Schodack landing,NY
Goodall Viper,AHPC Viper,Nacra I20
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Posted: Jun 13, 2013 - 11:15 PM
That's interesting. My old mast base was a 4 rivet and it still deformed and cracked. I guess it isn't a foolproof fix.
Edited by efinley on Jun 13, 2013 - 11:19 PM. -
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Posted: Jun 14, 2013 - 05:54 AM
Where are you located, I have a front crossbar -
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Posted: Jun 14, 2013 - 06:41 AM
The "creaking and moaning" was probably the mast base working due to the loose rivets.
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Jeff
Houston TX
1986 Hobie 18 Sail# 13031
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Posted: Jun 14, 2013 - 12:11 PM
I'm in NorCal but I actually already have a replacement xbar, thanks for the offer though.
It is tough to say whether the xbar deformed and that caused the looseness or if the looseness caused the deformation. Regardless one of those almost certainly caused the cracking.
I have a hard time believing that the loose mast base caused the mast base to deform like that, there was a noticeable dimple at the leading edge of the mast base in the xbar.
