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  Topic Review (Newest First)
10-19-2015 07:17 PM
Re: Coronado 41

Originally Posted by Osprey2015 View Post
Thanks so much Jeff !....
Point of order, Adrian... those were JonB's images, not Jeff's
10-19-2015 07:04 PM
Re: Coronado 41

Thanks so much Jeff ! Especially for the "Keel Prepped for Mounting" image. I am Cast Iron. Sand Blasted keel, removing all gelcoat to expose metal in 1996. Found it to be a bad casting with void holes at bottom that had been packed. Treated everything with corrosion inhibitor and recovered with epoxy and faired. Time has probably arrived to do what you have done. You've helped identify the path forward.
Many thanks,
10-19-2015 06:37 PM
Re: Coronado 41

I would first ascertain if the keel is lead or iron - I was unaware that any but the Mk III Columbia 43's had lead and my comments only apply to iron keels..

Mine came out with the boat out of the water since they were so wasted - didn't want to chance removing anything in the water - yours sound the same or worse. As bad as mine were (see pics) the boat didn't leak a drop and it had motored up from Santa Monica to San Rafael like that

The studs came out quite easily and the threads in the keel only required chasing - I used a bottoming tap to get that little extra bit of thread. I thought the bolts looked kind of skimpy for a 10K Lb keel but upon checking I found they were more than adequate and well within standard engineering practice - many multiples of safety factor re: breaking strength. FWIW, while it was off, the boatyard picked it up and moved it around, flipped it over etc. using only a couple of "grade nothing" bolts to hold the forklift lifting brackets on it.

If I were one of your kids I'd pull the boat, drop the keel, not caring if the nuts sheared off, pull the studs with a stud puller - when the keel is off there is lots of exposed stud to grab - the bottom of the boat was very thick, like 1 1/2" IIRC. Then examine the state of the threads in the keel to see if they can be re-used. If not, I'd go up to the tap drill size that would prep the holes cleanly for bigger studs - whatever that size would be (I suspect 1"). Then re-tap the holes, reinstall new studs, sandblast, epoxy seal and fill & fair the fin while it's off, put it back on with new S/S floors and re-fair the joint on the hull.

That's what I did, minus oversizing the studs. Pics attached

It's a big job in the sense that you're dealing with huge weights and heavy equipment (pro's for that) but it's not difficult or technical - the worst part was fairing the hull joint - a very awkward position in which to do a lot of sanding & filling.
10-19-2015 05:49 PM
Re: Coronado 41

Understood. It appears that I have same attachment system and arrangement as shown in your thumbnails, with an additional two stainless bolts that were tapped after drilling new holes, between the existing front three pairs of keel bolts, 20 years ago. The plan would be to attempt extraction, if I can get enough metal in a pipe wrench to bite, and turn the bolts out, after soaking with anti seize fluids. Can't imagine though, that any cast iron metal threads would remain for new bolts after 43 years of water and galvanic activity. Have also always been concerned about integrity of the newer bolting. Is there a best path forward from your experience for this predicament? My cargo is my children.
10-19-2015 04:58 PM
Re: Coronado 41

It is my understanding that Coronado 41's began life as a Columbia 41 (bubble cabin version) and were designed with lead ballast. The few California ones had lead ballast. The east coast ones listed lead ballast as an option, but I have no idea whether any were built that way.

SS J-bolts were the standard keel bolt attachment method on lead keels, but galvanized steel thru-bolts were the standard on cast iron keels. The thru bolts generally terminated in a pocket that was sealed shut after the nut washer was installed. Some cast iron keels have a flange and the keel is through bolted through that flange using what was essentially a flat head carriage bolt. That type of bolt is an easier bolt to replace, but it is unlikely to be found on a boat this large.

Drilling and tapping cast iron for a replacement keel bolt is considered bad practice since iron castings tend to be inconsistent in hardness and may contain air spaces.

10-19-2015 04:30 PM
Re: Coronado 41

This is great news. The argument you make had been my own thinking for years. The problem is my memory of the owners manual for Hull #23, which clearly showed Jbolts in the keel, for the Coronado 41. Possibly this was a "typical", or sloppy editing, and meant for lead keel constructions; or maybe they had used epoxy in a void cavity for bolting. Met a homeless guy once who claimed to have worked in the Portsmouth yard that built the 41's. He said there was a lot of glass holding that keel in place. You couldn't drop it. My concern is worst case scenario storm and wave forces. (Don't know why they claimed Jbolting. Might find owners manual on board and try to finally resolve this contradiction) Problem is that there is nothing left of the nuts on the forward 3 pair. How did you remove studs, and did you retap with larger bolts??
Capt Pops
10-19-2015 01:12 AM
Re: Coronado 41

They were tapped. Iron keels always have tapped holes for the bolts because you can't put J-bolts in an iron keel. J-bolts have to go in the molten metal hence they would melt. Lead melts at so much lower a temp than steel that it can be done but iron & steel have essentially the same melting point.
10-19-2015 12:37 AM
Re: Coronado 41

Thanks for the thumbnails. And the comment that bolt replacement was doable in the water. I have owned my Coronado 41 for 32 years. Always thought the keel was attached with J Bolts. Tapped two sistered SS bolts in the 90's. Don't have owners manual. Were your bolts tapped or broken J's ??
Best Regards,
10-07-2015 04:50 AM
Re: Coronado 41

Only two Coronado 41's have sold through Yacht World in the last few years. The second one had all the major work done and looks quite nice inside and out except for the engine which is a bit of a mess.
The second one is much more typical .... an 8k boat that will cost 100k to make right.
10-07-2015 02:17 AM
Re: Coronado 41

This is my first post on I have been boating since I was a kid in the 50s' and lived aboard different sailboats for a few years in the past as well. I recently saw an early 70s Coronado 41 for sale on line for a very reasonable price and want to know the most likely problem areas. I saw several posts mention that the decks, mast step, keel attach bolts and floors are potential problem spots (like many other boats). I am handy around boats having worked on and maintained several sail and power boats over the years. The Coronado 41 looks like it would make a nice live aboard and the shoal draft model would make a nice ICW cruiser. Anyone have any other info on them? I look forward to any replys.
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