Finding Cabin Lights Electrical Short

[FastOlson]

The OP appears to moor in an area of warm temps and salty air. After decades have passed it's probably time to pull new tinned "boat cable" thru the boat and start over. What is an inconvenience today, with electrical circuits, may be a fire tomorrow.
Way safer/better to do some restoration.
(just my .02 worth....)

Speaking of older circuits, it's interesting that his boat was built in 1771 !

 

[Project_Mayhem]

The OP appears to moor in an area of warm temps and salty air. After decades have passed it's probably time to pull new tinned "boat cable" thru the boat and start over. What is an inconvenience today, with electrical circuits, may be a fire tomorrow.

Thanks for the search idea, and I'll start on that next weekend. I've had the boat about five years, so I can't blame those pesky PO's. Boat just recently moved down to salt water, so perhaps some growing corrosion in the past few months.

Recent move to saltwater

 

[Parsons]

Speaking of older circuits, it's interesting that his boat was built in 1771 !

Catalina's are well-built boats. Actually, 1771 is my sail and hull number (I didn't spring for the official U$ Sail number). At one time, it asked a bunch of stuff on your profile, which I dutifully filled, and now I cannot edit it. Also, it just displays parts of that profile over there on teh left, for some reason. Don't think anyone else ever noticed this, so ...

 

[RoyS]

In general, short circuits immediately trip a breaker and overloads trip a breaker after some time has passed. This problem appears to be an overloaded circuit and not a short circuit.

 

[FastOlson]

Catalina's are well-built boats. Actually, 1771 is my sail and hull number (I didn't spring for the official U$ Sail number). At one time, it asked a bunch of stuff on your profile, which I dutifully filled, and now I cannot edit it. Also, it just displays parts of that profile over there on teh left, for some reason. Don't think anyone else ever noticed this, so ...

Ah So! You are right about an unannounced change to the site. What was once personal info sorted out in individual lines and questions that I had filled in, is now all run together and hard to read. No editing function that I can find.
Is your Catalina a Mk 1 or 2?

Also, Roy's note about an "overloaded" circuit is worrisome. We do not want your boat to fail the "smoke test"...

 

[SycloneDriver]

Thermal camera. You may have to do the light bulb trick to allow it to build a little heat.

 

[Parsons]

Worked on this problem over the weekend - Why do we call them "sailboats" when they should be called "work boats"?
Like all boat problems, it was a combination of things, all linked to water getting into the boat. The overhead "eyeball" lights had some water behind them which caused a short. I don't know where it came from as the deck above is not damaged or bolted through, so it must have run along the plastic liner between the deck and head liner. The farthest back overhead light above the sink (shown in the background of this photo), was fine but no power. The jacketed line between the two lights is shorted, and it is sandwiched between the headliner and deck so cannot be removed. The negative (black) is not continuous, but the positive (white, which somehow is not on the ABYC color chart!) is connected to both the power and negative, somewhere along the line.

Considering that I cannot repair the only line to the after light, I'm going to abandon that light and cover the headliner hole with a plate, already taped off the abandoned line ends. The forward light is fine (except for water leaking on it). I'm going to just clean and replace, and hope it doesn't rain! Actually, I'm more worried about deck rot now than bad lights. Perhaps I'll buy a waterproof light from Marinebeam.

PS - for all the folks on this board that made me feel bad about "branching" off of an existing power line for a 12v outlet or tank monitor using those clip-on insulation cutters, this is how the professionals at Catalina did the power take-off for those overhead lights I'm talking about (inside the head locker):

Thanks for all of the help and advice on my little problem!

 

[uncledom]

That is some scary stuff. Glad you found the problem, good luck finding the leak.

 

[JamesG161]

Here is a wild guess where the water is entering in....

Base of mast drainage!

If that area is not clean, water level rises and enters the boat, where masthead wiring comes into the boat.
Jim...

 

[Parsons]

Base of mast drainage!

Sounds like some painful experience - but not applicable in my case. Keel stepped mast, so my "base of mast" and wire exit is a good 6 feet below those lights! Unfortunately, the closest piercing of the deck in that area is the central opening port under the boom vang. Not looking forward to investigating such a big job.

 

[jssailem]

It is referred to as "Mission Creep", "Project add on's" or "Change Work Orders". Working on an older boat, in my experience, is always blessed with discovery of more work to do then anticipated.

 

[Parsons]

Someone on one of these boards has the signature, "If you own a boat, you'll never be out of work". Applies in this situation.
Anyone know how hard it is to re-bed a Lewmar hatch? I've got all the stuff, just need to figure out how to remove the trim to get at the screws.

 

[jssailem]

Picture please. There are so many different designs. On mine the screws are easily accessed from above with the hatch open.

 

[Capt jgw]

This sounds to me like a device, not a wire. I'd start with disconnecting/removing all bulbs and other loads (if any) then add them in, one at a time, while taking ammeter measurements.
Edit: If the breaker trips with all loads disconnected, it would prove it's a wire or socket/switch.

My thought too. The delay sounds like something getting hot then shorting out. Like a light bulb.

 

[Parsons]

Thanks for the encouragement, @jssailem - Lewmar hatch with a dozen #12 screws easily accessible from the top. Unscrewed, cleaned out old butyl tape and polished both surfaces, renewed butyl tape (thanks Mainesail), and re-screwed. Probably an hour's work, with most of it being cleaning. Hopefully, no more water on the lights.