Celestial Navigation? Forget it! - Page 22 - SailNet Community
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post #211 of 330 Old 04-08-2008
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You bring the star down to its reflection in the water, but you have to divide the resulting angle in half--since you're actually measuring twice the angle of the object's elevation. Generally using a thicker darker liquid will work better. I've used blackstrap molasses. I've also used motor oil... but the molasses is easier to get rid of.


Thanks sailingdog and tjaldur for them answers. I'll have to try that some time.

But isn't that sort of a misnomer?
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post #212 of 330 Old 04-20-2008
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Food for thought:

2 days ago I was typing away on sailnet when "KABOOOM!" all my portlights were filled with yellow light and instantly the sound of thunder rocked the boat. It was right on top of us.

My neighbor 4 boats away is missing an antenna at the masthead and his other is bent, as is his windex. My next door neighbor's GPS booted up spontaneously, though it seems undamaged.

For my part, my shorepower cord has a blackened charred connector, as does the dock receptical. Shorepower is out, though neither the dock side or boat side breakers tripped. My wireless internet antenna/amplifier is Wi_FRYED.

Haven't checked all the rest of my electronics but I seem to have fared pretty well, though I don't think I got anything near a direct hit. It was a reminder to me the big metal stick that points to the sky (I have 2) is a fine lightning attractor and when lightning is even close it can fry electronics.

MedSailor

PS, my cat's hair seems frizzier too.
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post #213 of 330 Old 04-20-2008
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WOW Med, that sounds frightening!

You are the first person I have ever talked to who had an actual strike on their boat. Look forward to hearing more details about what happened or at least what damage there is if you find anything else is broken. I think some extra Pounce treats for kitty, and maybe even a catnip toy!

What are you pretending not to know ?

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post #214 of 330 Old 04-21-2008
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A new Hunter 44 (or 42, anyway, it was big and fresh from the factory) was at a mooring at our club when we were having lunch and looking out the second floor windows. Storm rolls in...KABOOM...and I see an eight-foot browish plume of smoke from the mast of the Hunter, which is apparently an artifact of Nature's spot welding.

We went out later and saw that an irregular line of blackened holes, about the size of quarters, had been punched out of the forward starboard hull a couple of inches above the waterline. None AT the waterline, but the holes were patched with tape and back went the boat to the shop, having never been sailed.

Apparently, it started fine and all electrical parts worked and the motor turned over immediately. The charge went down the mast and somehow into the hull (instead of into the keel, which is what I thought that big plate was for), where it meandered out the bow.

I think lightning is essentially chaotic when it hits fibreglass boats, and sometimes you get off lightly and other times every wire on the boat melts or you get a fist-sized hole out the bottom. A couple of guys at the club have been struck (the boat, not them) while sailing and have been knocked flat and bruised but not actually electrocuted. They both said that it's quite an overwhelming experience and that no dramatic depiction does it justice.
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post #215 of 330 Old 04-21-2008
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Quote:
Originally Posted by MedSailor View Post
...
For my part, my shorepower cord has a blackened charred connector, as does the dock receptical. Shorepower is out, though neither the dock side or boat side breakers tripped. My wireless internet antenna/amplifier is Wi_FRYED.
That's interesting.. if only because it shouldn't have happened. You could have had a dockside fire on your hands!!...

It sounds to me like the surge would have come through the earth wiring - not the power supply circuit and that you and your neighbour were on the same shorepower circuit and that your connection was earthed and his wasn't - meaning his system was earthed through your boat!?!

I'm guessing that there were no GFI's in use anywhere - not that they would necessarily have tripped anyway, but they might have helped.

Bad luck about your Wifi... I'd suggest you go buy a surge diverter for your shorepower connection ASAP. You might not be so lucky next time.

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"Honestly, I don't know why seamen persist in getting wrecked in some of the outlandish places they do, when they can do it in a nice place like Fiji." -- John Caldwell, "Desperate Voyage"
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post #216 of 330 Old 04-21-2008
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So what this really means that a lightening strike at sea will mean that you are doing celestial, whether you want too or not. Wiping out your electronics will be a bummer.
And the 4 day arrival announcing rule 'down under' added on top of this will really make your day the pits.
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post #217 of 330 Old 04-21-2008
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So what this really means that a lightening strike at sea will mean that you are doing celestial, whether you want too or not. Wiping out your electronics will be a bummer.
And the 4 day arrival announcing rule 'down under' added on top of this will really make your day the pits.
I guess these days if something like that happened and you had to go 'down under' without a radio it's best to check in with the national media as soon as you get there too to plead your case lol.

"Hello australia! I'd like to check in ..."
"You're going to jail sir ..."

"Hello media! I was struck by lightning and couldn't check in before getting to aussie and now they're going to throw me in jail ..."
"I'll transfer you to our international incident department, please hold ..."

What are you pretending not to know ?

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post #218 of 330 Old 04-21-2008
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I guess these days if something like that happened and you had to go 'down under' without a radio it's best to check in with the national media as soon as you get there too to plead your case lol.

"Hello australia! I'd like to check in ..."
"You're going to jail sir ..."

"Hello media! I was struck by lightning and couldn't check in before getting to aussie and now they're going to throw me in jail ..."
"I'll transfer you to our international incident department, please hold ..."
Well.. we do like to keep people out unless they have a valid excuse.

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"Honestly, I don't know why seamen persist in getting wrecked in some of the outlandish places they do, when they can do it in a nice place like Fiji." -- John Caldwell, "Desperate Voyage"
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post #219 of 330 Old 04-21-2008
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A friend of mine said, "forget the sextant, if your GPS fails, just follow the airliner contrails or the cruise liners, and you'll make it to port."

What do you think of that philosophy?

Hud
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post #220 of 330 Old 04-21-2008
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A friend of mine said, "forget the sextant, if your GPS fails, just follow the airliner contrails or the cruise liners, and you'll make it to port."

What do you think of that philosophy?
Interesting... If you're sailing in the Carribbean or the Med, maybe this would work, but if you're doing the Sydney-Hobart or in the Roaring Forties you'll be an icy-pole before you see any of either mode of transport.

On the other hand, if you followed the Japanese whaling fleet...

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"Honestly, I don't know why seamen persist in getting wrecked in some of the outlandish places they do, when they can do it in a nice place like Fiji." -- John Caldwell, "Desperate Voyage"
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