replace/repair hex head bolts front crossbar nacra 570
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Posted: Aug 02, 2017 - 12:47 PM
nacra 570 washes away in big storm, retrieved but front cross bar light weight aluminum(compared to 5.7) front cross bar seemed loose so my friend tries to tighten them up but hex head bolts stripped! we have done this repair before by drilling out bolts, but has anyone just sunk 2 more bolts port& starboard? if there is aluminum bar below cross bar there could be a possibility that new bolts could hold especially since stripped bolts seem to be holding anyway. Ideas suggestions invited -
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Posted: Aug 02, 2017 - 01:16 PM
I don't know the anatomy of your boat but ....
most beam bolts screw into some type of metal plate that is epoxied into (and under) the fiberglass hull
this is what "marries" the beam to the boat
unless the "aluminum bar below cross bar" is glassed into the boat .. it will do no good
if the "aluminum bar below cross bar" is the dolphin striker - this will do NOTHING but secure the striker to the beam (which it already is)
unfortunately - you will probably have to drill out the bolt like before
This is the rear beam plate used by nacra 5.2 - it is similar in size to the one epoxied into the front of my mystere 5.5 and 6.0
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Posted: Aug 02, 2017 - 02:01 PM
I don't think just blindly drilling holes into your boat is a good idea. As stated above, there needs to be some type of backer inside the hull to accept the bolt, and this needs to be threaded so it will give the bolt something to screw into.
Also, your description really isn't clear. When you say the bolts are stripped, does that mean the heads are stripped (i.e., you can't put a wrench on the bolt) or does it mean the threads are stripped (i.e., when you put a wrench on the bolt, it just turns but doesn't tighten or loosen).
You need to figure out what's going on with the bolts and what they thread into (my guess from your description is the bolts just spin and most likely the backing plate inside the hull has broken free and is just spinning). Then figure out a proper solution. Don't just start whacking away at your boat with a drill in the hopes that it will fix the problem.
sm -
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Posted: Aug 02, 2017 - 02:05 PM
This depends what year your boat is. It's not quite as easy as just putting in new bolts but it's not super hard.
New 570s are actually through bolted.
The previous edition has a stainless steel thread insert the can be dug out and replaced.
Can you please email me photos of the area and the year of your boat.
Todd@nacrasailing.com -
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Posted: Aug 02, 2017 - 04:19 PM
If you are talking about the backing plate that the bolt screws to to hold the beams in place there are two ways to I would go about fixing this..
A.) Drill out the backing plate and re-thread (tap out) the hole with the next size up bolt.. this is the easy route but you'll have a Hodge Podge of bolts holing your beam on... plus you'll need to drill out the associated hardware.. just make sure you get the right tap for the thread pitch for the bolts you'll be using
B.)My preferred method would be to get a HeliCoil set, drill out, tap, insert HeliCoil, and done... you can use the original bolts... I have used these on numerous occasions including the front beam of my 5.8.... even had one in a VW engine spark plug hole for about 5 years with no problems.
Which ever route, just be sure to put a snot load of anti-size on the bolts and threads when reassembling
Edited by JohnES on Aug 02, 2017 - 04:21 PM.
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John Schwartz
Ventura, CA
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Posted: Aug 09, 2017 - 07:38 PM
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Posted: Aug 09, 2017 - 10:57 PM
I wish I had dug those bronze lugs out on all of the other positions a year ago when it would have been easy to do and easy to upgrade. Now two are fixed and 14 others with those crazy sharp corners are just sitting there waiting to bite me in the ...............
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dg
NACRA 5.2 #400
This End Up
Original owner since 1975
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Posted: Sep 07, 2017 - 11:28 AM
we r finally going to repair the 570, rear cross bar/beam hex cap bolt snapped off. afraid to disassemble 8 yr old cat, thinking of drilling 7/16 hole through entire beam and pontoon and inserting threaded stainless rod with nuts and washers. does anyone know how big/ dimensions of backing plate, should i drill inboard or outboard of old bolt? good luck to everyone in fla i have a Dart 18 in Oakland Park and hope it weathers Irma having lost 6 cats to hurricanes/n'or easters off fire island ny
