Check your chain plates, thats pretty simple. The aft lowers on my h37c looked fine 6 months ago at survey. then we broke one. careful examination of the lower made the problem clear. the aft chain plates are mounted strait up and down. but the load on the chainplate is not vertical in line with the chain plate. this caused the chain plate to bend and finally break. I have replaced mine with a new chainplate and changed the angle of the chainplate so as to line up with the load. We moved the bottom end of the plate outboard about 2 inches or so and redrilled and mounted the chainplate. All of the damage was hidden in the core one could not see the damage unless the plate was removed. So given that my boat an 84 is newer than most of the 37c,s out there i suggest everyone should look at these plates. The surveyor did not catch it and neither did I.
- Status
Thanks Ed.
Good reminder. Gene and Tom wrote about this a few years ago. I forget what Gene did but Tom replaced his with heavier stainless custom chainplates. He also upgraded the shrouds from 1/4" to 9/32" at the same time. I remember that Tom mentioned that angle problem also.
Good reminder. Gene and Tom wrote about this a few years ago. I forget what Gene did but Tom replaced his with heavier stainless custom chainplates. He also upgraded the shrouds from 1/4" to 9/32" at the same time. I remember that Tom mentioned that angle problem also.
I think its a pretty important one
to investigate and to change. the loads on the chain plates should be as straight down the plate as possible. What really was eye opening was that i could not see any of the faults untill i removed the plate form the boat!
to investigate and to change. the loads on the chain plates should be as straight down the plate as possible. What really was eye opening was that i could not see any of the faults untill i removed the plate form the boat!
Everyone who owns stainless
Should know that stainless will rot away when sealed away from oxygen in a salt water environment. At least, that's what they told me when I worked on submarines. We used monel hardware below the waterline & in areas that would trap water. The chainplate and the deck and the caulking could conspire to seal oxygen away from the metal. I think monel is too soft to be used as chainplates so the best bet is to pull & inspect chainplates every few years. Also, as I recall, stress causes corrosion in stainless. All the pull should be straight line. I think I better go drillsome new holes in my boat.
Should know that stainless will rot away when sealed away from oxygen in a salt water environment. At least, that's what they told me when I worked on submarines. We used monel hardware below the waterline & in areas that would trap water. The chainplate and the deck and the caulking could conspire to seal oxygen away from the metal. I think monel is too soft to be used as chainplates so the best bet is to pull & inspect chainplates every few years. Also, as I recall, stress causes corrosion in stainless. All the pull should be straight line. I think I better go drillsome new holes in my boat.
It's a problem!
I guess I haven't been dilligent in posting in a while - the chainplates are one of the most serious potiential problems I've found. I didn't angle mine, although that seems like a pretty good idea. I did make new ones out of 3/8" stock to replace the 1/4" original ones. It's not difficult to do yourself, which I dod for most of them. The first 2 I replaced were done when we were getting ready to go cruising and I had no time. A local machine shop did them for me at $40 each. He had no idea what a chainplate was, but simply duplicated what I took him. I upgraded all my shrouds to 5/16" from the 9/32" that were installed when I bought her.
I guess I haven't been dilligent in posting in a while - the chainplates are one of the most serious potiential problems I've found. I didn't angle mine, although that seems like a pretty good idea. I did make new ones out of 3/8" stock to replace the 1/4" original ones. It's not difficult to do yourself, which I dod for most of them. The first 2 I replaced were done when we were getting ready to go cruising and I had no time. A local machine shop did them for me at $40 each. He had no idea what a chainplate was, but simply duplicated what I took him. I upgraded all my shrouds to 5/16" from the 9/32" that were installed when I bought her.
H33 chainplates
During a major refit of my 79 H33, I removed all of the chainplates, and examined them. Perhaps because in the H33, the chainplates are pretty well aligned with the shrouds, there was no cracking or any other deterioration of the chainplates. On the other hand, the stem fitting to which the forestay turnbuckle is attached had a distinct egg shaped hole where the clevis pin had deformed the fitting. To remedy apparent result of stress concentration, I had washers welded on each side of the fitting as whown in the photo to spread the load to the pin. It was quite curious that the six chainplates of the H33 already had this stress distributing washer welded to the fittings.
During a major refit of my 79 H33, I removed all of the chainplates, and examined them. Perhaps because in the H33, the chainplates are pretty well aligned with the shrouds, there was no cracking or any other deterioration of the chainplates. On the other hand, the stem fitting to which the forestay turnbuckle is attached had a distinct egg shaped hole where the clevis pin had deformed the fitting. To remedy apparent result of stress concentration, I had washers welded on each side of the fitting as whown in the photo to spread the load to the pin. It was quite curious that the six chainplates of the H33 already had this stress distributing washer welded to the fittings.
Attachments
- Status