Flying Compass

[Trim50]

Wheel’s adventure reminded me of something I did which was equally stupid with much of the same outcome.

About two years ago when I installed my new genset, I ran all new wiring for the AC on the boat. When I was done with the job, I plugged-in the shore power. As soon the shore power was plugged-in, I heard a humming sound. When I climbed down the companionway, I could smell smoke but couldn’t see any. A few seconds later, I heard a loud WHOOOOMPPPP from the cockpit and I turned just in time to see my compass flying about 15 feet into the air off the helm station pedestal. It was followed by a burst of flames and dark black smoke coming from the top of the pedestal. The compass landed on the deck a few feet away.

I quickly grabbed a fire extinguisher and started spraying it down into the pedestal opening left by the flying compass. When the extinguisher was empty, I jumped off the boat and shut-off the shore power at the breaker panel. When I returned to the Salon and opened the engine compartment, a cloud of thick black smoke filled the entire boat and began flowing in a substantial cloud through the open hatches.

At this point I was in a complete state of panic trying to find my second fire extinguisher. After a few more minutes, it seemed that the smoke had subsided and the root cause was the AC power. By this time 15 or so people from the dock had collected outside wondering if they should call 911.

When things settled down, a group of us stood around for hours trying to explain why the compass blew-off the pedestal.

So here is what happened. I somehow wired the shore power ground to hot (don’t ask). When I plugged the power in, the only path to ground for the AC was through the engine, up the throttle cable making a small arc to the steering chain, down the chain to the quadrant and out the rudder post to the water. The 20ft of nylon sheath on the throttle cable melted in seconds and filled the compartment under the helm until the smoke mixture became combustible. Once the mixture of gasses was sufficient, the electrical arc ignited the gasses in the pedestal and blew the compass off like a projectile from a canon.

A very exciting event and surprisingly, I was able to fix everything for less than $200. My Karma account took a major deduction that day.

[svHyLyte]

So. Did the compass need a bit of adjusting ex post facto?

Cheers,

svHyLyte

[RichT]

Hey Trim,
We all make mistakes, I'm just glad yours was minor and you didn't suffer injury. I told Wheels I would someday relate the story of how I welded an end wrench to the door of a DC9, and this seems an opportune moment.

Working night line one night, and needed to change a major relay in the control panel, which is part of the bulkhead just behind the pilot, and in front of the pax door. Should have shut the power down on the entire a/c, but someone else was working a problem that needed power up, so I figured I would be very careful. First dumb mistake. I had shut off power to that system, but apparently one of the other relays had also failed and was inadvertantly providing power. The relay was a main feed 150 amp breaker, with terminals about the size of a battery cable. I put a wrench on the terminal nut but because it had never been removed before, it was siezed on the bolt. Instead of pulling it toward me, and guarding it with my other hand, I decided to smack it with the palm of my right hand. It gave loose, spun, and because it was a box end and stayed on the nut, went right into the door hinge.The wrench immediately arced, turned red, and welded itself to the door. The relay started smoking. I jumped into the cockpit and killed all the power switches. After a bunch of nasty remarks from the other techs, calling me a dumb****, and the supervisor chewing my butt, I finished the job.

My point is that I learned a lot from that one incident. Mainly, NEVER work on an electrical system until all power is off or safeguarded. The other thing I've learned over the years is that if I turn on power, and I hear, see, or smell anything out of the ordinary, i.e. your "humming", something you wouldn't normally expect or that may portend a problem, first thing to do is KILL THE POWER. It may not prevent all damage, but it would certainly mitigate it, and hopefully, prevent a total disaster (you know, boat going down in flames kind of thing).

Fortunately, I have never had to call someone's spouse, kids, parents, to tell them their loved one is in the hospital, or worse, at the morgue, but it has happened to guys I know, and it isn't easy, or pretty.

So, to all our fellow cruisers everywhere, in the words of that famous TV cop, Phil Esterhouse of NYPD BLUE, "LET'S BE CAREFUL OUT THERE".

RichT.

[Trim50]

The reason that I mis-wired the power is pretty understandable if you have experienced it before. The boat was built in the late 70s and wiring code has changed since then. Unfortunately I wasn't thinking about this when I re-wired and simply copied the old wiring colors at the backside of the plug.

[GordMay]

Originally Posted by Trim50

...So here is what happened. I somehow wired the shore power ground to hot (don’t ask) ...
The reason that I mis-wired the power is pretty understandable if you have experienced it before. The boat was built in the late 70s and wiring code has changed since then. Unfortunately I wasn't thinking about this when I re-wired and simply copied the old wiring colors at the backside of the plug.

I don’t understand.
In North America, Black has been AC “Hot”, White = “Neutral”, and Green has been “Ground”, for as long as I can remember (I’m old enough to have Alzheimer’s).
There has been no significant change in DC colour codes, excepting the “optional” change of DC “Negative” to Yellow (to avoid confusion /w AC Hot).

[Trim50]

My understanding from the surveyor was that older boats circa 70s were not inspected for code. My boat's AC was Black (ground), Red (hot), White (neutral). I guess what I should have said, was that boats were later required to meet code...this is just what I was told. So, you can see why I re-wired the boat.

[Alan Wheeler]

That is just plain haleriouse Trim50. I love it.
Folks, I am also a electronics/electrical qualified. It is all very well to say that this is what should happen or be done or what ever, but in reality when it goes wrong like that, you don't have time to react. The effect and affect is usually so puzzleing, that for a few seconds you are trying to comprehend just what on earth is taking place. So we all stand there like stunned mullets thinking, wha?? coool!!! wha?? oh crap!!!
And as for those working on live circuits, it is often us that have the understanding of electricity that tend to take the biggest risks. For me I suppose, it is because part of my electrical career meant I had to work on live equipment and you learn't to do things in certain way's. But put that into other realms of life, where equipment wasn't meant nor designed to be worked on live, then we tend to take those learn't work techniques and use them as lazy attitudes. Problem is, the two words, lazy and techneques are a a dangerouse combination.

[Maddog]

I have to say that so far I have been lucky. I have always found my mistakes and others before they could kill me. It's that moment of realization where your head tingles and all you can say is, "Sh*t!".

The biggest for me so far. When I got my boat the PO had the AC wired directly to the plug with no main breaker. The surveyour told me it was in danger of burn to waterline as it sits in the dock. (Before anybody gets crazy, I was gifted this boat. I did not buy it, though I have paid for it many times. No, it is not for sale). I installed a 30amp double pole breaker like the book says. Thought I had it right. Was wireing the a gfi outlet with the breaker off. Hands, strippers, screwdriver all over the wires and outlet. I decide to test my work and plug in a radio. Remember, the breaker is still off. Music starts playing before I throw the switch. I think it was Blue Oyster Cult, "Don't Fear The Reaper", (OK I made that part up, but music did play). Once again I had to stop for the day, take a shot of Bourbon and change my shorts.

That was a powerful lesson. Eevn if you thinks it's right, check it again.

[Trim50]

It certainly got the adrenaline rushing. After all, I just finished installing a $5000 genset and all I could imagine was that I had just torched it. Thankfully it was mostly smoke and not much fire. Plus, I was already planning to replace the throttle and shifter cables.

After this, I installed two automatic FireBoy systems and 3 new fire extenguishers.

[Pblais]

Trim50,

We have a lot of confessions of things we have done wrong threads but this one clearly rises above all of them. Exploding compasses just won't be matched without injury (I hope). You only learn from the ones you walk away from. If someone else can make the trip none of us need to repeat it.

The lesson is that there is no limit to what a small error in judgment can do. It also shows there are important small clues prior to bad things happening if you only can stop for a moment and think. There is hope for us all! Everything thing you know can be a warning of greater disasters.

[Trim50]

Only time has made it funny! This is the first time I've shared that story with anyone off the dock.

[TX Sailor]

My wife youngest son and I took his new to him Hobie 16 to a unfamilar lake where a friend kept her boat. It was a nice day and the wife and son were on the Hobie and I was on the friends boat with her. We were trying to keep a eye on the Hobie but there was no way we could keep up and finally lost sight of them. Then the wind came up to about 25 or so mostly gusts. We finally spotted them and they had been turtled several times, the last time a powerboat pulled them back over and somehow jamed the jib halyard and ripped the travler track completely off the frame. They had a main they couldn't use and a jib half way down they they could do nothing with. We got things under control and towed them back to the ramp.

The boy was very discouraged and about in tears about his boat and the wife was trying to keep his spirits up. I told him we would fix the boat. We got it on the trailer at the very busy ramp and the wife ask "where do you want me to go" I said "anywhere out of the way"

The boat was just sitting on the trailer and I was standing on the trailer holding the bridal wires to keep it from sliding off. The wife took off up the ramp and turned into a little lot that looked to be a good place to lower the mast and tie things down. Just as she turned the bridal wires jerked out of my hands along with most of the skin on my palms. The boat hit the ground and the trailer kept going. I had no clue what had happened until I looked up and saw the highline wire she had snagged with the mast.

I think the only reason I wasn't fried was that the boat had a comp mast tip installed just for the reason of not conducting electricity. We had a regular mast at home and had nearly used it.

It was over a year before the boy showed any intrest in his Hobie but he did finally fix it and has sailed it quite a bit since.

[OldYachtie]

Call me a luddite, buy why put AC on a boat at all? Most stories about the premature death of big, expensive house battery banks have to do with AC charger malfunctions. Why not just forget AC, bolt a big second alternator to your engine, have lots of power when off the grid, and have less expense, worry, and complication? See: (I have no connection with them,) Jack Rabbit Tim Dunn, perfectly happy with no AC

[HAwkcharter]

Trim50,
Since this seems to be confession day for electrical.
About ten years ago, I found reason to move my boat 10 minutes from where I was in the Atlantic.

The move went well, but after I stopped the boat, I heard what I thought was the bilge pump running. Thinking it would shut off in a minute or two (it didn't) I wasn't alarmed. Well, I was alarmed when I smelt smoke.

Immediately I started to search for the source of the smell. When I lifted the hatch cover the cockpit sole, smoke bellowed forth. The bilge motor running turned out not to be the bilge motor running; it was the starter motor and now the battery cables were overheating, the motor was still running.

Doing what we all are told to do, I immediately turned off all the batteries at the master switch.

One would think, that would cure it wouldn't they?
Well the motor kept running!! And the smoke was now quite thick. I peered through it trying to see why and how the starter motor was still engaged, and why the battery master switch didn't disconnect all power.

Panic was close at hand now, as the smoke became thicker. The battery cables crossed over each other, and the insulating plastic/rubber around the copper cables had melted and subsequently fused a permanent short circuit, bypassing the battery master switch!

The battery posts were too hot to handle, and I burned my hands when I grabbed them (remember I was close to panic?) in a vain attempt to remove the cables.

The starter was still singing along, the cables were still melting and the smoke was now coloring the sky. Fire was going to be the next thing.
I grabbed the only tool I could find in a hurry, a pair of "nips" (wire cutters) and desperately clipped at the positive cable. When the cable was cut, more like nibbled through, I thought that would end it. It didn't. Recall, I said the cables were fused together, and until I cut the other cables to the second battery, she was still making smoke and sparks. WHEW! The heart was pumping dudes.

Today, I have all my cables run in a manner where they cannot overlay each other if a similar thing occurred.
P.S. The origin of the problem, was the ignition siwtch had not returned and kept the starter motor running, all the while. On board fire, is no fun.

HAwk (a lesson learned)

[Alan Wheeler]

It's bloody scary is all I can say.
Sorry to hear your story, but I am sure glad I am not the only one.