Weird (wired) situation

[DannyS]

I ran into a weird situation today on a friend's boat. I was looking over his very nicely done re-installation of custom dinghy davits after a corroded weld gave way last summer. He had the davits rebuilt and added a short reinforcing shroud from the davit to an unused chainplate meant for a mizzen mast that was never installed on his particular boat. While oooing and aaahing at the new setup, I touched the shroud and it was really warm, not too hot to touch but close! The other shroud was fine. The chainplate seemed to be the culprit with the heat conducting up the shroud. We went around and touched all of the chainplates on the boat and only one was really warm, one was kind of warm and the rest were cool. It was about 9 am in the morning so the sun had not been beating down on anything just yet so that was not the issue. I assume the chainplates are all bonded to the keel. Any ideas as to the cause?

 

[Bill Roosa]

Well that is pretty thin info to go on.
My guess would be differential heating. the sun was up and that particular chain plate was facing it (or one of the surfaces) directly. The rest were at greater angles and still reflecting most of the sun's energy.
However, is there something below that might be getting hot and transferring the heat up?
also did the rest of the plates heat up eventually and did that one cool down after sunset?

 

[DannyS]

Yeah Bill, I know there's not much info there to accurately diagnose, just wondering if anyone had a guess. I know it definitely was not from the sun. Everything was shaded on that one and the shrouds that were in the sun were not hot.

 

[Skipper]

Is the chainplate fully external?

How close is the shorepower entry to the chainplate? Or, since the chainplate is aft likely at the engine room, is the water heater output pipe touching the (if internal) chainplate? Or any other non-engine heat source, assuming the engine had not been running.

Also, had you been running the davit motor? ...if motorized. IE is it properly grounded, etc.

 

[DannyS]

Is the chainplate fully external?

How close is the shorepower entry to the chainplate? Or, since the chainplate is aft likely at the engine room, is the water heater output pipe touching the (if internal) chainplate? Or any other non-engine heat source, assuming the engine had not been running.

Also, had you been running the davit motor? ...if motorized. IE is it properly grounded, etc.

Shore power is close but not that close. Not sure how it's configured down below. Water heater is an interesting thought. The chainplate is not external, it pops up through the teak toerail. No engine had been running and no davit motor.