Celestial Navigation? Forget it! - Page 5

piclarke · #41 (**permalink**) 10-08-2002

Thanks I agree - but I''M selling mine. I have not used it in 15 years. It is in mint condition.The sight reduction tables make room for instruction manuals.

Most of the time one can''t get a horizon because another Island is in the way and as you have stated I find there are to many over cast days.The G.P.S. gives me the answer in 1 second flat. Star and moon shots I can''t see the horizon once the bright light hits the mirror, accordingly I have never been able to take a night sight. However I believe there are people who can, I''M not one of them.

Mental stimulation - I prefer to play chess with the crew or read a Tom Clancy book.
All the best with your sextant.
<img src="http://members.sailnet.com/profile/uploads/piclarke/PhillipClarke_pic.jpg">
CHEERS,
Have a better than average day:
PHIL:

feprice · #42 (**permalink**) 10-14-2002

Come on you guys. What''s all this either/or crap? GPSs are so cheap and sextants so fundamental, why would a serious offshore sailor be without both? I''m not an offshore sailor and don''t own a sextant. I am on my second GPS. My first went defunct in rather desperate straits in the middle of the proverbial dark and stormy night, forcing me to rely on dead reckoning in a 30-40 knot wind with rocky shores all about. A sextant would have been useless and the GPR crapped out when it got wet (inside the wheelhouse). You can bet when I go offshore I will have GPS and sextant.
It''s just cruising.
Cheers, Frank

piclarke · #43 (**permalink**) 10-15-2002

Good on you mate: This is tremendous news, please take my details, keep them on record and contact me when you decide to go offshore. I''M sure my sextant which is in mint condition would love to come out of it''s box and see the sun, moon and stars.

Sales of new ones have dropped dramatically in the last 8 years manufacturers are considering going out of production.

I look forward to hearing from you.

conradconrad · #44 (**permalink**) 10-16-2002

SO WHAT KIND OF A SEXTANT DO YOU HAVE AND HOW MUCH DO YOU WANT FOR IT ????? SEND ALONG A COUPLE OF THOSE BACK UP FOOD CONTAINER BATTERY RIGS ALSO THANKS CONRAD(EL RATON)

markcash · #45 (**permalink**) 10-19-2002

As a political scientist and not a sailor (yet), I have to say some word of caution to those who rely solely upon GPS for navigation. Electromagnetic pulse from an nuclear explosion in space can knock out all unshielded electronics on the earth below. Military GPS might survive, but those fragile things we use are very susceptable. With the proliferation of nuclear weapons into the hands of "rogue" states and possibly terrorists groups, it might be wise to have a backup form of navigation handy. Anyone who reads Tom Clancy novels should know that! Without a sextant, you might not be able to find your way home.

tsenator · #46 (**permalink**) 10-21-2002

Uh Oh !.....Tell you what. If there was a nuclear blast I think finding your way home would be the least of your worries. I would think that might be the last place I''d go towards.....

BTW a simple and easy (and mostly effective) way to help protect against EMP for delicate electronic instruments is to encase them totally in a "Faraday Cage" which for all practical purposed is a fully enclosed metal box. What you could do is buy an inexpensive handheld GPS for under $200 and wrap it in Aluminum foil and place it in a metal box (I have heard people place them in the oven temporarily and that might work).

But the reality is that in case of a nuclear war the military GPS satelites most likely would either be knocked out or turned off ..... BUT the method I talked about (Faraday cage) can help protect delicate electronic instruments in case of a lightening storm.

Ok.....with all that said, I would probably have a sextant and manual/tables to work one in case of a real dire emergency if I was blue water sailing.

redwoodtree · #47 (**permalink**) 10-27-2002

This is a very interesting thread. As a new member of sailnet, I agree with MaryBeth that these discussions are especially useful to new sailors.

But, seriously why would you sell your sextant?? I mean, Phil, I have this image of you selling your sextant and then regretting it sometime in the future. With barrells of batteries on board what difference does it make if a sextant is stored away in a box in there as well?

Hopefully you''re just exaggerating. But remember, never sell you sextant in anger and never say "I haven''t needed it in 15 years" because that''s just like ASKING murphy to come and prove you wrong ;-)

jmachelski · #48 (**permalink**) 10-28-2002

You state that "Today''s charts are far better than those used in the past." Not always true. Check your chart and you will find that many of the surveys used were performed years ago. This is a good reason not to rely on electronics without a healthy dose of common sense. One of the problems now is that a GPS is often more "accurate" than the chart, so we sail blithely on unaware of the rock about to rip our bottom out. No matter what method used, GPS or sextant, we must always be aware of what''s around us and exercise caution. Belts and suspenders ain''t all bad, so why not have all reasonable tools on board for safety? If you are coastal cruising, up to date charts, tide tables, good compass, etc. are probably sufficient, assuming you can take bearings. If you are offshore, redundancy, including electronic and nonelectronic means of navigating, should be the standard. After all, it''s only your life you''re gambling with, right?

jmachelski · #49 (**permalink**) 10-28-2002

You state that "Today''s charts are far better than those used in the past." Not always true. Check your chart and you will find that many of the surveys used were performed years ago. This is a good reason not to rely on electronics without a healthy dose of common sense. One of the problems now is that a GPS is often more "accurate" than the chart, so we sail blithely on unaware of the rock about to rip our bottom out. No matter what method used, GPS or sextant, we must always be aware of what''s around us and exercise caution. Belts and suspenders ain''t all bad, so why not have all reasonable tools on board for safety? If you are coastal cruising, up to date charts, tide tables, good compass, etc. are probably sufficient, assuming you can take bearings. If you are offshore, redundancy, including electronic and nonelectronic means of navigating, should be the standard. After all, it''s only your life you''re gambling with, right?

jklewissf · #50 (**permalink**) 11-21-2002

I sailed my boat from san francisco to hawaii in 94. The first 13 days were overcast and I would not have had a clue about where I was if I did not have a functional GPS on the boat.

Navigating off shore without GPS is much more irresponsible than heading to sea without a sextant.

I keep my old sextant on board and a current copy of the almanac (which contains adequate sight reduction tables for emergency use.) But, I would not go out and buy an expensive sextant if I had it to do today. I''d get a cheap plastic one.

Another good way to do emergency navigation is with a cheap am radio that can be found at radio shack for uner $10. It has to be a cheap one with a very directional antenna. Just put the radio on a compass rose on your chart and rotate it until the signal nulls (positions of am stations are on many charts). That gives you a line of position that is not to bad. If you get a rock lop, a cw lop, and a classical lop you will probably know where you are within 5-10 miles if the stations are spread far enough apart.