Circumnavigation without instruments - Page 5 - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > General Interest > General Discussion (sailing related)
 Not a Member? 


Like Tree29Likes
Reply
 
LinkBack Thread Tools
  #41  
Old 02-28-2013
smurphny's Avatar
Over Hill Sailing Club
 
Join Date: Feb 2009
Location: Adirondacks NY
Posts: 2,637
Thanks: 47
Thanked 52 Times in 51 Posts
Rep Power: 6
smurphny is on a distinguished road
Re: Circumnavigation without instruments

It was not all that long ago when everyone used DR. The use of RDF and LORAN are fairly recent although they seem like ancient stuff now. I used to enjoy the challenge of navigating in poor visibility across the gyre in Block Island Sound, trying to avoid the Sow and Pigs It's probably only in the last 30 years that sailors have slacked off in their use of DR with the incredible marvel of GPS integrated into plotting gadgets.
__________________
Alberg 35: With a philosophical flourish Cato throws himself upon his sword; I quietly take to the ship.
Reply With Quote Share with Facebook
  #42  
Old 02-28-2013
Capt.aaron's Avatar
KNOT KNOWN
 
Join Date: Dec 2011
Location: Guanaja, Bay Islands, Honduras
Posts: 1,320
Thanks: 1
Thanked 19 Times in 19 Posts
Rep Power: 3
Capt.aaron is on a distinguished road
Re: Circumnavigation without instruments

Quote:
Originally Posted by flandria View Post
Boasun.... Yes, you are correct. However, things are a little more complicated and uncertain when you add drift (current) and leeway (especially when traveling under sail). After a few miles, depending on conditions, your actual course vs. DR course may start to diverge noticeably. I'll omit small "discrepancies" in steering the course... Your point that you may well be without celestial observations for a prolonged time is certainly valid and thus one should always be prepared for "the worst" and keep a DR log up at all times, regardless of other gadgets available.
That's true. I cross the straights of Fla. and then the Yucatan Channel all the time under sail. The currents are on the paper chart and I make a vector, calculate the set and drift, average my steering course based on compass swing. The trick is to do it often, twice an hour when you are really in the throws of the strongest currents and running down a big sea. I DR and look at a hand held GPS a couple of times a day to see how close I am to correct. Never been more than a few miles off which is close enough to get with in sight of land, at which point you are piloting by points of land, LOPS off of land marks etc.
__________________
" Some are boat wise and some are other wise"
Reply With Quote Share with Facebook
  #43  
Old 02-28-2013
Junior Member
 
Join Date: Feb 2013
Location: West coast of Canada.
Posts: 7
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
JimAndTricia is on a distinguished road
Re: Circumnavigation without instruments

I agree with Shandk25. Let's not diminish his accomplishment. Anyone who steps off the end or normalcy for whatever reason, as long as they don't hurt anyone else by doing so, has my respect. We need more people in this world who are willing to be different. I would think that back in the days of the Vikings, anyone who pulled out a little piece of plastic with a bunch of numbers on it and relied on it to cross oceans would be considered pretty out there too.
Reply With Quote Share with Facebook
  #44  
Old 02-28-2013
krisscross's Avatar
Senior Member
 
Join Date: Feb 2013
Location: NC
Posts: 1,436
Thanks: 22
Thanked 75 Times in 75 Posts
Rep Power: 2
krisscross is on a distinguished road
Re: Circumnavigation without instruments

If we ever get another solar flare like this one (or close):
all the satellites will be toast, rendering our GPS systems totally useless. Knowing at least the minimum about traditional navigation seems like a must for any open sea sailor.
smurphny likes this.
Reply With Quote Share with Facebook
  #45  
Old 02-28-2013
Classic30's Avatar
Once known as Hartley18
 
Join Date: Aug 2007
Location: Melbourne, Australia
Posts: 4,404
Thanks: 23
Thanked 30 Times in 30 Posts
Rep Power: 8
Classic30 will become famous soon enough Classic30 will become famous soon enough
Re: Circumnavigation without instruments

Quote:
Originally Posted by Capt.aaron View Post
That's true. I cross the straights of Fla. and then the Yucatan Channel all the time under sail. The currents are on the paper chart and I make a vector, calculate the set and drift, average my steering course based on compass swing. The trick is to do it often, twice an hour when you are really in the throws of the strongest currents and running down a big sea. I DR and look at a hand held GPS a couple of times a day to see how close I am to correct. Never been more than a few miles off which is close enough to get with in sight of land, at which point you are piloting by points of land, LOPS off of land marks etc.
FWIW, it is simply very unsafe (and might even be considered extremely stupid!) to approach the southern coastline of Australia without an accurate fix and using DR only... at any time in history, including now.

IMO, if you must do it because you have no other alternative about the only way to approach is the way this guy did, but even then, given that you're entering what is effectively a big bay on a lee shore it's a pretty risky business, because as soon as you fix your position (and there are no landmarks to do that with) you need to turn around and get the hell outa there ASAP - and, congratulations, you just added hundreds of miles to your course.

The alternative is to stand on and hope for the best.. but very few who have tried this survived. They don't call this the "Shipwreck Coast" for nothing.


This is what it looks like at low tide on a nice day:
__________________
-
"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"

Last edited by Classic30; 02-28-2013 at 08:03 PM.
Reply With Quote Share with Facebook
  #46  
Old 02-28-2013
Omatako's Avatar
Senior Member
 
Join Date: Sep 2003
Location: Auckland New Zealand
Posts: 2,371
Thanks: 0
Thanked 25 Times in 22 Posts
Rep Power: 11
Omatako will become famous soon enough
Re: Circumnavigation without instruments

Quote:
Originally Posted by Boasun View Post
So learn DR Navigation. And practice it always when underway. It will help you find the port you are shooting for without all of those modern gadgets.
You only need to know: Time, Speed and Course to find your way.
Yes but the guy we're discussing never had any instruments. How do you get time, speed and course without instruments? DR without instruments is like a party without people. It ain't gonna happen.

Statistically, the current that runs along the equator moves more water than the collective volume of every river in the world. How do you DR that without instruments?

I said it in one of my earlier posts and I agree with SimonV, this voyage had a great deal of luck involved. And Simon, your checking "once or twice a day" amounts to over 500 possible checks that the instrument-less circumnavigator couldn't do. Remember he was at sea for one and a half years. Go figure.

Thor Heyerdahl did a significant voyage on a papyrus (or something) raft and was also declared a super-navigator. But if he hadn't of drifted into the island his voyage ended on, he would have drifted into another with the same claim to fame - eventually he had to hit something. He may have been dead by then but he would have made landfall somewhere .

DR is a science that requires numbers - no numbers, no DR. Simple.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

__________________

"Two possibilities exist: Either we are alone in the Universe or we are not. Both are equally terrifying."

Arthur C. Clarke
Reply With Quote Share with Facebook
  #47  
Old 02-28-2013
Classic30's Avatar
Once known as Hartley18
 
Join Date: Aug 2007
Location: Melbourne, Australia
Posts: 4,404
Thanks: 23
Thanked 30 Times in 30 Posts
Rep Power: 8
Classic30 will become famous soon enough Classic30 will become famous soon enough
Re: Circumnavigation without instruments

Quote:
Originally Posted by Omatako View Post
Yes but the guy we're discussing never had any instruments. How do you get time, speed and course without instruments? DR without instruments is like a party without people. It ain't gonna happen.
Well, the guy did have an hourglass... and presumably enough pencils and paper to keep track. Therefore it is possible to get your numbers like this:
* Time: a really rough idea of the time of day by picking local noon on a good day using a stick at arms length as a home-made crossstaff and re-setting your hourglass-chronometer by that. (worked for the Polynesians..)
* Speed: a WAG using the old method of occasionally dropping something overboard and counting how long it takes to pass a known distance along the hull. (well you'll get a number to write down, anyway!).
* Course: Knowing the sun's track across the sky for the time of year during the day and picking your angle to the Pole Star/Southern Cross by night ("two points off the starbd crosstree!") it is possible to know roughly where you're headed.
.. none of this will give you an accurate DR position by any means - but it's better than nothing.

Yep, he certainly needed a lot of luck - and, like Thor Heyerdahl, would have relied on eventually running into something, but don't forget that common practice for hundreds of years before the sextant was invented was to "run your easting down"...


EDIT: One thing about hourglasses is that they do wear out with repeated use and get more and more inaccurate every day. I assume he took a box of them and had some system for swapping them out.. like the old windjammer captains did.
__________________
-
"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"

Last edited by Classic30; 02-28-2013 at 08:21 PM.
Reply With Quote Share with Facebook
  #48  
Old 02-28-2013
Capt.aaron's Avatar
KNOT KNOWN
 
Join Date: Dec 2011
Location: Guanaja, Bay Islands, Honduras
Posts: 1,320
Thanks: 1
Thanked 19 Times in 19 Posts
Rep Power: 3
Capt.aaron is on a distinguished road
Re: Circumnavigation without instruments

As far as the south coast of Australia goes, just don't go there. Sail past it and turrn north when you don't see it any more. Drive down there from Sydney and have a look from the top. ( at low tide, that is an awesome photo)

Speed, I still use a chip log my Grandfather built. Thorw it off the stearn and count.
Direction, well the sun comes up and goes down and if the stars are out Pleadease (sp) alway's points east. ( I use this all the time because my compass light is still broke.)

Thor Hyeredahl. Who here has besides me worked for him. I know his niece and dated her Daughter as well. He was a freak'n genius. And he broke the mold on isolation vs. transmigration through observation and proof through re-enactment voyages.

The argument here is more about not having a foundation in the art/science
of basic simple deductive reasoning. Using what you have available in nature, coupled with some simple and non-problamatic instruments, like a compass and an Timex. Not needing 10,000 people to get up and go to work keeping the interactive systems in check just so you can know where you are.
smurphny and ShoalFinder like this.
__________________
" Some are boat wise and some are other wise"

Last edited by Capt.aaron; 02-28-2013 at 09:01 PM.
Reply With Quote Share with Facebook
  #49  
Old 03-01-2013
Classic30's Avatar
Once known as Hartley18
 
Join Date: Aug 2007
Location: Melbourne, Australia
Posts: 4,404
Thanks: 23
Thanked 30 Times in 30 Posts
Rep Power: 8
Classic30 will become famous soon enough Classic30 will become famous soon enough
Re: Circumnavigation without instruments

Quote:
Originally Posted by Capt.aaron View Post
As far as the south coast of Australia goes, just don't go there. Sail past it and turrn north when you don't see it any more. Drive down there from Sydney and have a look from the top. ( at low tide, that is an awesome photo)
Hey, it ain't that bad!.... (actually, on second thought, maybe it is) but it's all that some of us have to play in.

To be safe you just need to:
1. Have checked the weather forecast AND the tides before exiting "The Rip".
2. Have nice day (for the purposes of this exercise, storms, rain, high winds, night and/or fog are NOT classed as "nice days"!)
3. Hope like H*** you know EXACTLY where you are in relation to those cliffs at all times!




EDIT: Please ignore Aaron's well-meaning advice to just "sail past it and turrn north when you don't see it any more". Here's a listing I found of a few who've tried that over the decades...
__________________
-
"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"

Last edited by Classic30; 03-01-2013 at 12:41 AM.
Reply With Quote Share with Facebook
  #50  
Old 03-01-2013
Capt.aaron's Avatar
KNOT KNOWN
 
Join Date: Dec 2011
Location: Guanaja, Bay Islands, Honduras
Posts: 1,320
Thanks: 1
Thanked 19 Times in 19 Posts
Rep Power: 3
Capt.aaron is on a distinguished road
Re: Circumnavigation without instruments

Quote:
Originally Posted by Hartley18 View Post
Hey, it ain't that bad!.... (actually, on second thought, maybe it is) but it's all that some of us have to play in.

To be safe you just need to:
1. Have checked the weather forecast AND the tides before exiting "The Rip".
2. Have nice day (for the purposes of this exercise, storms, rain, high winds, night and/or fog are NOT classed as "nice days"!)
3. Hope like H*** you know EXACTLY where you are in relation to those cliffs at all times!




EDIT: Please ignore Aaron's well-meaning advice to just "sail past it and turrn north when you don't see it any more". Here's a listing I found of a few who've tried that over the decades...
Indeed, and with any luck I will have the opportunity to ignore my own advice and visit the area. If I find my self there I will certainly have 2 chart plotters, a radar, ais, paper chart, 3 compass', rdf, and a flock of caged sparrow's to let fly free and follow!
Classic30 likes this.
__________________
" Some are boat wise and some are other wise"

Last edited by Capt.aaron; 03-01-2013 at 08:09 AM.
Reply With Quote Share with Facebook
Reply

Tags
circumnavigation , marv creamer , new jersey , no instruments , sailing


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Then she said how about a circumnavigation? killarney_sailor General Discussion (sailing related) 11 01-07-2010 07:18 PM
Circumnavigation Chapterone Cruising & Liveaboard Forum 9 04-24-2009 03:00 PM
Circumnavigation WannaSail14 Seamanship & Navigation 40 11-01-2006 11:03 AM
circumnavigation CindyC Cruising & Liveaboard Forum 0 01-09-2006 04:07 PM
A circumnavigation? jerryrlitton Boat Review and Purchase Forum 12 06-28-2004 12:56 PM


All times are GMT -4. The time now is 05:32 PM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012