Sextant - Fly Fishing Forum
Stripers and Coastal Gamefish Stripers, Blues, Inshore tuna!

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
  #1  
Old 11-29-2007, 01:01 PM
striblue's Avatar
striblue striblue is offline
President of CAC
 
Join Date: Aug 2000
Location: Plymouth and Chatham, MA
Posts: 7,518
Sextant

My new Davis 25 sextant came today and I am excited about learning how to use it. Obviously I will bring it on board when out with friends since I have no boat...yet ... to learn how it works . I have always wanted to do that. It will go with a new celestron telescope I now have down in Chatham which has a motor driven declination etc.... Despite the GPS technology how many boat owners carry a sextant with them...just curious. I suspect there use is for greater distances off shore, but I was just wondering.
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2  
Old 11-29-2007, 02:33 PM
Smcdermott's Avatar
Smcdermott Smcdermott is offline
Jonesin...
 
Join Date: Mar 2002
Location: Rhode Island
Posts: 1,220
Definitely a cool thing to know but on small boats I don't see much use in reality.

On my boat I have GPS (boat and handheld backup), paper charts and compass. I also have marine VHF (handheld and fixed) and personal location beacon. I think you would need to be pretty far offshore to use a sextant as taking a rough heading in my boat should get you within sight of land and familiar landmarks.

Sean
Reply With Quote Quick reply to this message
  #3  
Old 11-29-2007, 02:43 PM
josko josko is offline
Registered User
 
Join Date: Jan 2000
Location: Cape Cod
Posts: 564
Celestial navigation is a great hobby but it's not practical for actually navigating, especially a small boat. Learning sight reduction techniques is hard enough - doing them aboard a small boat is for those tougher than me.

Still, try standing on a beach, doing some rudimentary sightings and going through the math yourself. For a graduate level treat, get a book on early Polynesian navigation methods and try to piece it together for yourself. Remember, they had no knowledge of compass, no north star, and still managed to hit a 1 mile island dead-on after 2000+ miles of sailing.
If you're starting from scratch, Bowditch http://www.irbs.com/bowditch/ is worth reading.
Reply With Quote Quick reply to this message
  #4  
Old 11-29-2007, 02:49 PM
jfbasser's Avatar
jfbasser jfbasser is offline
Pencil me in.....
 
Join Date: Aug 2002
Location: The Nearside of the Middleside
Posts: 1,070
Quote:
Originally Posted by striblue
My new Davis 25 sextant came today and I am excited about learning how to use it. Obviously I will bring it on board when out with friends since I have no boat...yet ... to learn how it works . I have always wanted to do that. It will go with a new celestron telescope I now have down in Chatham which has a motor driven declination etc.... Despite the GPS technology how many boat owners carry a sextant with them...just curious. I suspect there use is for greater distances off shore, but I was just wondering.
Modern cruise ships have the best electronics in the world with all types of backups, but still carry a sextant. The use of a sextant gives you a perspective on navigation fundamentals, orienteering, and the solar system that you cannot get any other way....enjoy it!..when my radio navigation work bores me I take out the sextant and some sight reduction tables.Remember that on 2 days of the year you can determine your Latitude directly without the use of a chronometer.
__________________
Basser
Certified Stan Gibbs Cape Cod Canal Classic Flyrodder
Reply With Quote Quick reply to this message
  #5  
Old 11-29-2007, 03:03 PM
vtloon's Avatar
vtloon vtloon is offline
Registered User
 
Join Date: Jan 2007
Location: Lake Champlain, VT
Posts: 488
Sextant

John, Celestial Nav is a challenging but fascinating way to get it done. Your sextant will require some other support tools: a precise chronometer and the almanacs (these days that can mean an atomic clock and a celestial nav calculator. Then, charts and a table or flat surface for plotting. Taking sights (even your noon sun sight) from a small boat is usually pretty difficult, but it can be done. A good winter read would be "Mariner's Celestial Navigation", Capt. W.P. Crawford. Let me know if you can't get it locally.

Best backup for GPS: a good set of charts, compass and an RDF for when the fog sets in.
Reply With Quote Quick reply to this message
  #6  
Old 11-29-2007, 04:10 PM
Rip Ryder Rip Ryder is offline
Registered User
 
Join Date: Oct 2002
Location: Chatham Ma.
Posts: 279
Sextant

John,

You can look into a class on that at Mass Maritime Academy in their weekend classes they have for the general public. Go to their website and look up the schedule or you may also be able to get a class at New England Maritime in Hyannis. Again, check their webpage.

Personally, I have never used one.

Capt Keith
Reply With Quote Quick reply to this message
  #7  
Old 11-29-2007, 04:59 PM
striblue's Avatar
striblue striblue is offline
President of CAC
 
Join Date: Aug 2000
Location: Plymouth and Chatham, MA
Posts: 7,518
Thanks Guys for that input. I have also read that a small pocket sextant can also be used when on dry land with the use of the artificial horizon block, providing the sun is out and you can then calculate both longitude and latitude by doing the readings on the local noon meridian passage. I will follow up on all this just to know about it and how to do it. Latitude will require tables, etc....something else to learn whether I use it or not. I know that the GPS does the job, but the history Josko mentions and a book I read on latitude and longitude and the determination of GMT and the difficulties the early voyagers had with determining latitude is interesting to me.
Reply With Quote Quick reply to this message
  #8  
Old 11-29-2007, 05:14 PM
jimS's Avatar
jimS jimS is offline
obsessive/compulsive
 
Join Date: Aug 2001
Location: salt
Posts: 1,202
Send a message via AIM to jimS
John, I admire your retro/brain teasing approach to navigating to distant shores. I too am curious about things I don't understand, but if there is math involved, I'm all thumbs.

Now, if your long range plan is to circumnavigate the globe for purely fishing purposes, I'll volunteer, and defer to others for the techy type challenges. I'm really a good salad maker.

Penguin is, I presume, penning a post on this topic. Since he is a pilot/captain, and you are the navigator, the obvious name for the boat would be...
Reply With Quote Quick reply to this message
  #9  
Old 11-29-2007, 06:25 PM
Penguin's Avatar
Penguin Penguin is offline
d'PhlightlessPhlyPhisher
 
Join Date: Oct 2001
Location: Kape Kodistan, People's Republik of Taxachusetts & Penguinia
Posts: 1,586
Navigation alternatives...

So...Dead reconning of sorts...
Destination Otis ANGB and your navigator is Major Roger Peltier...
You're somewhere over the Atlantic heading west...
28,000' & 350mph...
Landfall...
You see glaciers and icebergs...turn left!
You see palm trees and sandy beaches/bicinis...turn right!
Follow the coast until you see Otis!
John...JUST KIDDING!

Good on you!
The sextant shot is an almost lost art...GPS is like the meteor that doomed the T-Rex!
My navigator had one in my C-130 and it was a pisser to use...'always a sigh of relief when we would hit MidWay or Johnson Island but it works if done properly.
You'll need the special tables and logs and a suspected location to get you in the ballpark and going...Soundz like a fun project on your back deck in July!

Ooops!
What's that?!
A car just drove past the house...'better go check it out!
Reply With Quote Quick reply to this message
  #10  
Old 11-29-2007, 06:52 PM
striblue's Avatar
striblue striblue is offline
President of CAC
 
Join Date: Aug 2000
Location: Plymouth and Chatham, MA
Posts: 7,518
Thanks Pete... I can simply start taking readings at certain locations, even on the beach and then compare to what I come up with by checking my Handheld GPS to see how acurate I can be, But I know I will need tables.... and have a good watch (Rolex Submariner).... so this will be a good start.
Reply With Quote Quick reply to this message
  #11  
Old 11-29-2007, 08:35 PM
Paxton Paxton is offline
Registered User
 
Join Date: Jul 2002
Location: Central Mass and Chatham
Posts: 924
John.....you just made it official.....fishing season is over and winter is near
Seriously......I give you credit in your pursuit of this interest.....lost arts are always a valued find.
I just may dedicate my winter to trying to figure out how Stonehenge was built and why....God knows I will be more successful doing that than I was fishing the fall migration
Ron
Reply With Quote Quick reply to this message
  #12  
Old 11-30-2007, 12:08 PM
gordonh gordonh is offline
Registered User
 
Join Date: Nov 2000
Posts: 37
sextant

Davis offers a "lifeboat sextant" that is considerably less sophisticated than the one John bought, but it's only $39. I bought one of these to learn a little, and for me that's probably good enough. I think you can get to within a few miles with the cheapie and probably within a mile or so with John's, but I haven't gotten into it far enough yet. You certainly can develop a lot of respect for traditional navigators quickly by fooling around with a sextant!

The cheap unit isn't bad for figuring out whether the tree you are about to cut down will miss the house or not, might be worth $39 for that alone.
__________________
GLH
Reply With Quote Quick reply to this message
  #13  
Old 11-30-2007, 01:17 PM
RayStachelek's Avatar
RayStachelek RayStachelek is offline
Registered User
 
Join Date: Oct 2000
Location: Rhode Island & beyond
Posts: 720
Quote:
josko Celestial navigation is a great hobby but it's not practical for actually navigating, especially a small boat. Learning sight reduction techniques is hard enough - doing them aboard a small boat is for those tougher than me.
Josko said it well. Want something simple and hit it dead nuts even in a fog.

What do birds use and they have tiny brains at that ?
Reply With Quote Quick reply to this message
  #14  
Old 11-30-2007, 01:41 PM
striblue's Avatar
striblue striblue is offline
President of CAC
 
Join Date: Aug 2000
Location: Plymouth and Chatham, MA
Posts: 7,518
Ray, what are you talking about? Birds? I did not follow what you are saying
Reply With Quote Quick reply to this message
  #15  
Old 12-01-2007, 07:11 AM
FishHawk FishHawk is offline
Registered User
 
Join Date: Feb 2000
Posts: 2,039
Electronics are great until the batteries go dead. I always have a compass in my pack just in case. Ray the birds have micro sextants built into their brains.
FishHawk
__________________
FishHawk
Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Fly Fishing Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 09:34 PM.



Copyright Flyfishingforum.com (All Rights Reserved)