NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Teaching seamanship
From: Dave Weilacher
Date: 2004 Oct 14, 16:23 -0500
-----Original Message-----
From: Frank Reed
Sent: Oct 14, 2004 3:19 PM
To: NAVIGATION-L@LISTSERV.WEBKAHUNA.COM
Subject: Re: Teaching seamanship
Derrrick Y wrote:
"Is CN a good backup to GPS; is it a worth while study? Each of us has our own answer. For me, it is - because I never want to be in a situation where I lose all my electronics because of a short circuit in the battery compartment."
Do you carry a handheld GPS unit as a backup? In an emergency kit? Regardless of one's enthusiasm for celestial navigation, if the concern is safety, a spare GPS receiver is likely to be far more valuable than a sextant.
You mentioned Murphy (as in Murphy's Law). That "everything that can go wrong will go wrong" logic applies to cel nav every bit as much as it applies to GPS. A simple scenario: you are crossing the Atlantic and you're one day from Antigua. You're under a tropical depression. The sky is covered with clouds for hundreds of miles. And you're hit by lightning. None of this is exotic or low probability, right? Your main GPS system is now fried. The sky is overcast. You're heading for land. So you get out your sextant and...
1) trade it for a $50 handheld GPS unit from a passing freighter.
2) wait out the storm until you can take sights with it.
3) toss it overboard as an offering to Neptune and sail on carefree.
Frank R
[ ] Mystic, Connecticut
[X] Chicago, Illinois
From: Dave Weilacher
Date: 2004 Oct 14, 16:23 -0500
Frank;
You pose a fascinating question deserving of thought.
I would guess the following.
1. heave to and see if it blew out a through hull.
2. clean pants
3. fix a drink
4. stop shaking (what the drink was for)
5. check paper charts for hazards to approach Antiqua. (like I hadn't done this a gazillion times already)
6. Plot DR from log of waypoints I've been religous about recording.
7. Get boat back on ships compass course that I was recording along with GPS bearing and track.
At a day out of Antiqua, I'd expect to be able to see it on DR nav alone. Interesting though, that you must know where you are AND where you are trying to go for any kind of navigation to do you good.
Dave W
-----Original Message-----
From: Frank Reed
Sent: Oct 14, 2004 3:19 PM
To: NAVIGATION-L@LISTSERV.WEBKAHUNA.COM
Subject: Re: Teaching seamanship
"Is CN a good backup to GPS; is it a worth while study? Each of us has our own answer. For me, it is - because I never want to be in a situation where I lose all my electronics because of a short circuit in the battery compartment."
Do you carry a handheld GPS unit as a backup? In an emergency kit? Regardless of one's enthusiasm for celestial navigation, if the concern is safety, a spare GPS receiver is likely to be far more valuable than a sextant.
You mentioned Murphy (as in Murphy's Law). That "everything that can go wrong will go wrong" logic applies to cel nav every bit as much as it applies to GPS. A simple scenario: you are crossing the Atlantic and you're one day from Antigua. You're under a tropical depression. The sky is covered with clouds for hundreds of miles. And you're hit by lightning. None of this is exotic or low probability, right? Your main GPS system is now fried. The sky is overcast. You're heading for land. So you get out your sextant and...
1) trade it for a $50 handheld GPS unit from a passing freighter.
2) wait out the storm until you can take sights with it.
3) toss it overboard as an offering to Neptune and sail on carefree.
Frank R
[ ] Mystic, Connecticut
[X] Chicago, Illinois
Dave Weilacher .IBM AS400 RPG contract programmer