Patrick — I wonder if the “orangey” stuff you saw is the same stuff they used between the headliner and the cabin top; some sort of liquid adhesive. Sounds a lot like what I’ve found in the headliner of my boat.
— Fred Fred Street -- Minneapolis S/V Oceanis (1979 C&C Landfall 38) -- on the hard in Bayfield, WI :^( > On Jan 30, 2017, at 9:23 AM, Patrick Davin via CnC-List > <cnc-list@cnc-list.com> wrote: > > Progress! Just to follow up in case anyone's interested or for future > reference, I managed to get one U-Bolt out. I wrote a blog post on the > methods and results: > https://svviolethour.com/2017/01/29/rerig-part-4-stuck-navtec-u-bolt-chainplates/ > > <https://svviolethour.com/2017/01/29/rerig-part-4-stuck-navtec-u-bolt-chainplates/> > > tldr: Lots of heat plus a 24" pry bar / breaker bar. > > I found an Ericson owner who used a similar method - shroud tension plus > heat. He thinks shroud tension was around 1000 lbs, but he had 3/8" Navtec > u-bolts. Using a lever arm calculator, I calculated the upward force it took > on my 1/2" bolts was around 2000 lbs. > > Interesting aspects once I got it out: lots of aluminum corrosion dust from > the backing block, but the SS was spotless. Bedded in butyl, not silicone. > And the deck core here was not wood! Some kind of hard composite I don't > recognize - light orange / peachy in color. Very good news because the core > is pristine. > > I doubt it's an epoxy coring from a prior owner (since A) it's doesn't look > like epoxy, and B) the bolts looked like they'd never been pulled). Around > each U-Bolt the deck has square area about 8"x8" where it's clear something > different was inserted between the fiberglass. I thought it was marine ply, > but I guess they could've used some kind of board of composite or plastic. > > The one question I haven't figured out yet is, if the U-bolts were not > leaking (I've never observed water from them, even in heavy rains), how did > the aluminum corrosion happen? I suspect small moisture over time (interior > cabin moisture? Or small amounts getting in from deck while under sail when > the u-bolts are under flexion / tension?) contributed to it. Just need a > small amount of moisture to get a galvanic medium on the less noble aluminum > next to the SS. The material loss is insignificant however. > > -Patrick > 1984 C&C LF38
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