sextant??

[Joe Pyrat]

Wasn't it one of these that Tania Aebi used to start with because it looked less intimidating then discovered it was warped and that's why she couldn't get consistent readings or even readings that made sense?  Once she switched to the more complex looking better sextant things started working just gine.

[dnice]

Wasn't it one of these that Tania Aebi used to start with because it looked less intimidating then discovered it was warped and that's why she couldn't get consistent readings or even readings that made sense?  Once she switched to the more complex looking better sextant things started working just gine.

Yeah she had a warped one she got used (i think it was the one her dad used on their previous atlantic crossing), I don't think it was less intimidating... just free/cheap.

I also think her book is what started the whole fear and rumors of plastic sextants. They are precise enough for navigating a small boat as long as they are not warped... the only way to warp them is to leave them sitting out in the sun (or other heat sources). Other than that you can damage them in any of the same ways you can damage a metal one.

And just as a side note: Tania had taken an online course and pretty much failed it... Her father had taken a class and she had his books from it...she understood the math, but had never used a sextant on a boat before leaving NY. She managed to navigate all the way to the pacific using DR and getting positions from passing ships, and occasionally using her Radio beacon locator thing.
Finally somebody pointed out the problem with the sextant and she got a new one (used) and was then able to become confident with her skills.

Not that I recommend navigating by DR and radio only  :)  I just think that shows how much people over-think everything instead of just getting out there and doing it like tania did. I think what makes a person a good sailor is their ability to improvise and adapt to whatever is thrown at them, it has nothing to do with being an expert at anything before you leave. Tania is a perfect example of this, she had every intention of navigating by sextant, but she also had never used one at sea before... she made due with what she had at the time, and the rest is history.

[AdriftAtSea]

Actually, IIRC, she left it out in the sun and the heat of lying in the sun allowed it to warp.  That's what I believe it said in her book, Maiden Voyage.  She got an old Frieberger sextant after that, and that worked just fine.

[Joe Pyrat]

Seems like I remember her RDF being an old transistor radio.  She had no idea where she was on her way to Bermuda but was able to tune in a Bermuda radio station and would just sweeping the horizon with the radio until the signal peaked and sailed in that direction.  She was lucky, but also creative which got her through.

[thistlecap]

Just a couple points, if I may.  The sextant I've used for the last 35-40 years has been a Simex Jr.  It has been an outstanding instrument.  At the lower end of quality sextants, it has a telescope, verier micrometer, four shades, and 120-degree limb, and has done everything I've ever needed.  I doubt the purchase of a Plath can be justified for use from the deck of a small boat IMHO, eventhough they are beautiful, unless you just need something to go with your caviar, champagne, and Rolls.
(2) For those who would like to master celestial, rather than just trying to learn enough to get by, I cannot recommend strongly enough taking the U.S. Power Squadrons courses.  They're comprehensive, and beyond minimal cost for materials, are free.  After taking those, I passed both elements of the Coast Guard celestial exams with perfect scores---a tribute to the courses, not me.
(3) To perfect the 'art' of celestial, the only way to do that is take several hundred sights from the beach so you can compare your LOP's with a fixed, known position.  This perfects your technique and shows what discrepancies are being created by what errors----not swinging the arc properly, not kissing the horizon or dipping the body, improper timing or recording techniques, using the sextant upright or inverted until you reach the last micrometer adjustment, sextant adjustment errors, getting equally reliable positions with sun, moon, planets or stars, etc.  Yes, I know people have taken off on a wing and a prayer, but I know a lot whose prayers weren't answered.  I know of one who set off from the West Coast in a 19-ft. boat.  He had a sextant and some books, and while he didn't even know pilotage, let alone navigation, he reasoned if he started sailing west and began reading, before he passed the Hawaiian Islands, he could figure out where he was and navigate the rest of the way.  While he was a great friend and I wouldn't disparage his accomplishment, I feel there's way too much luck needed there for the prudent navigator. 

[dnice]

Just out of curiosity... Where did he end up sailing to?

I certainly don't mean to tell anybody they shouldn't learn celestial.. I plan on learning it, and I plan on having a decent sextant aboard. By all means, learn as much as possible and, if you have the money, get a decent sextant. I just don't think you should stay home just because you don't have the $500 for one, or if you haven't 'mastered' it yet.

Tania was indeed lucky to make it to bermuda, but after that, she knew that her DR and her previous success in obtaining positions was enough to keep going. It was an informed decision. It wasn't until somewhere around the panama canal that she got her new sextant, making it that far was not luck. And I don't think she left NY relying soley on luck either, it just happened that way.

I would never recommend relying completely on luck in any situation, and I don't know anybody else who would...

[Captain Smollett]

I have a Davis Mk 15, and my personal best fix with it is 2 nm from a FIXED position on land.

With a plastic sextant, check the index error before each site.  That's what I do, though I've not noticed a LOT of problems with warping so far.

I'll second (or third, etc) the comment that to become proficient with it, you need to take HUNDREDS of sites from known locations.  It's a skill that demands practice.

But I find celestial extremely fun...the traditionalist in me, I guess.

Best of luck.       :)

[chris2998]

thanks guys yes the Davis Mk 15 I have read lots of good things on this one and I will probally order it next week so I can start practicing.
Thanks for the input

Chris

[Oldrig]

Wow! Looks like the Davis Mk 15 is available on sale for under $130!

Too bad I'm spending boat points this season on an emergency gas generator for the house (after being without power for 2 1/2 days during the last ice storm).

It looks like a much nicer unit than my antique Heath--which I guess I'll keep at home as a relic of an earlier time.

Merry Christmas!

--Joe

[thistlecap]

Response to dnice's inquiry.  He left Southern California, and if I remember correctly, landed on O'ahu.  The original boat was sold in Hawaii. He acquired an English pilot cutter by John Alden, and later sailed back through the Panama Canal, all of the East Coast, Azores, Med, Madeira, Canaries, Cape Verdes, Caribbean.  I won't mention his name or his boat's name.  I made the mistake of doing that once, and he got really upset.  He doen't like publicity.  However, he's a really neat guy that I feel privileged to have known.  In fact, one of our granddaughters is named after his daughter. 

[thistlecap]

Just another note related to the discussion of sextants and celestial navigation.  This is an all too common scenario.  I had stopped in Bermuda for one leg of a delivery and learned of a boat that was missing.  After it was towed in, I talked with the skipper.  We all make mistakes, so I'm not denigrating him or his problems in any way, but we all need to learn from mistakes, ours or others, rather than emulating them.  One of the big mistakes is relying on electronics rather than fundamental skills.  He and his wife had dreamed of buying a boat, retiring, and following the sun.  Life got in the way, and he never seemed to find time to learn celestial.  But, what the heck, the boat had loran and satellite navigation, and he could always study celestial as he went.  They took off for Bermuda.  Of course everyone knows, depending on installation, it's rare that loran will get you all the way to Bermuda.  He followed the loran to Bermuda, and Bermuda wasn't there.  He then followed the satellite navigation to Bermuda, and BERMUDA WASN'T THERE EITHER!!!.  I don't know what the problem was there.  Anyhow, he set up a search grid looking for the islands, a dangerous idea considering some of the reefs extend out to or a bit beyond the limit of visibility for the low-lying islands.  Three days into this search grid his wife mutinied, and said, "You will put out a distress call."  The navy homed in on his signal, and dispatched a plane, finding him 150 miles NE of the islands.  A ship went out and took him in tow, but of course the navy isn't going to spend two days towing him back at 6 knots.  Bounding through the seas at well above hull speed, the bower anchor unshipped and hung over the side with each wave slamming the anchor into the topsides.  It was indeed a sad sight to see a brand-new Cabo Rico with the hull stove in---a terribly expensive lesson, far above the cost of learning celestial.

[AdriftAtSea]

ouch...  having multiple, independent and redundant ways to confirm your position is a good thing.  Just curious as to how someone could be 150 miles off using satellite navigation, whether it was the older kind or GPS.

[chris2998]

Just another note related to the discussion of sextants and celestial navigation.  This is an all too common scenario.  I had stopped in Bermuda for one leg of a delivery and learned of a boat that was missing.  After it was towed in, I talked with the skipper.  We all make mistakes, so I'm not denigrating him or his problems in any way, but we all need to learn from mistakes, ours or others, rather than emulating them.  One of the big mistakes is relying on electronics rather than fundamental skills.  He and his wife had dreamed of buying a boat, retiring, and following the sun.  Life got in the way, and he never seemed to find time to learn celestial.  But, what the heck, the boat had loran and satellite navigation, and he could always study celestial as he went.  They took off for Bermuda.  Of course everyone knows, depending on installation, it's rare that loran will get you all the way to Bermuda.  He followed the loran to Bermuda, and Bermuda wasn't there.  He then followed the satellite navigation to Bermuda, and BERMUDA WASN'T THERE EITHER!!!.  I don't know what the problem was there.  Anyhow, he set up a search grid looking for the islands, a dangerous idea considering some of the reefs extend out to or a bit beyond the limit of visibility for the low-lying islands.  Three days into this search grid his wife mutinied, and said, "You will put out a distress call."  The navy homed in on his signal, and dispatched a plane, finding him 150 miles NE of the islands.  A ship went out and took him in tow, but of course the navy isn't going to spend two days towing him back at 6 knots.  Bounding through the seas at well above hull speed, the bower anchor unshipped and hung over the side with each wave slamming the anchor into the topsides.  It was indeed a sad sight to see a brand-new Cabo Rico with the hull stove in---a terribly expensive lesson, far above the cost of learning celestial.

good story I was telling a friend I was wanting to learn to use a sextant and he was like get a GPS and I was like what if it failed.. People these days just rely on electronic devices way way to much. I am guilty of this one to I have a cell phone. I have wonderd what happend if all cell phones died just for a day what on earth would people do.
I'm gonna order the mark15 sextant next week, I think it is very important to learn to use it, if I can only remember what website sold it for under 130 LOL

[s/v Faith]

Chris,

  Might want to take a look at this thead too;

  Okay, so the GPS is broken... Anyone teach me the sextant?

Lots of good lesson material, and links you might find helpful.

(and go back and read this thread from the beginning.  I think the KISS sextant is a cool idea you might want to take a look at.

[dnice]

Just another note related to the discussion of sextants and celestial navigation.  This is an all too common scenario.  I had stopped in Bermuda for one leg of a delivery and learned of a boat that was missing.  After it was towed in, I talked with the skipper.  We all make mistakes, so I'm not denigrating him or his problems in any way, but we all need to learn from mistakes, ours or others, rather than emulating them.  One of the big mistakes is relying on electronics rather than fundamental skills.  He and his wife had dreamed of buying a boat, retiring, and following the sun.  Life got in the way, and he never seemed to find time to learn celestial.  But, what the heck, the boat had loran and satellite navigation, and he could always study celestial as he went.  They took off for Bermuda.  Of course everyone knows, depending on installation, it's rare that loran will get you all the way to Bermuda.  He followed the loran to Bermuda, and Bermuda wasn't there.  He then followed the satellite navigation to Bermuda, and BERMUDA WASN'T THERE EITHER!!!.  I don't know what the problem was there.  Anyhow, he set up a search grid looking for the islands, a dangerous idea considering some of the reefs extend out to or a bit beyond the limit of visibility for the low-lying islands.  Three days into this search grid his wife mutinied, and said, "You will put out a distress call."  The navy homed in on his signal, and dispatched a plane, finding him 150 miles NE of the islands.  A ship went out and took him in tow, but of course the navy isn't going to spend two days towing him back at 6 knots.  Bounding through the seas at well above hull speed, the bower anchor unshipped and hung over the side with each wave slamming the anchor into the topsides.  It was indeed a sad sight to see a brand-new Cabo Rico with the hull stove in---a terribly expensive lesson, far above the cost of learning celestial.

good story I was telling a friend I was wanting to learn to use a sextant and he was like get a GPS and I was like what if it failed.. People these days just rely on electronic devices way way to much. I am guilty of this one to I have a cell phone. I have wonderd what happend if all cell phones died just for a day what on earth would people do.
I'm gonna order the mark15 sextant next week, I think it is very important to learn to use it, if I can only remember what website sold it for under 130 LOL

When I was in New Orleans after katrina, the cell phone networks stopped working for about 6 days or so (all phones, landlines and cells, were simply overloaded and rendered useless)... It was a serious wakeup call for me. I was amazed at how helpless the majority of people were without phones and TV. I really can't explain what it was like, it was simply disgusting...

GPS is great, but IMO the biggest problem with it, is that it is controlled by the US government. At any time, without notice, the DOD can simply decide not to allow public usage of the GPS system anymore.... Although its becoming more and more unlikely, the more americans are using it, the more of a commodity it becomes, and the govt. are more likely to implement a system of their own, and leave the current system for public usage....hopefully.

I think the most likely scenario is a lightning strike... You could loose every electronic onboard, including handhelds and whatever you had for backup... This could happen 20 miles from shore as well as 1000. So having backups is important, but as Adrift just pointed out, independent and redundant is the way to go... You need more than 1 way to navigate, and each of those ways should be entirely different than the other.

I would like to say that celestial nav will be my primary means.. It would be best that way, but more than likely I will rely on GPS and use celestial as a backup.... hopefully I will be diligent enough to keep practiced up and use GPS just to confirm my positions... How hard could it be to take a sight twice a day??? what else are you going to be doing on a 30 day passage :)

[AdriftAtSea]

Just remember—Celestial Navigation isn't really meant for use when in sight of land, since coastal pilotage is far more accurate. 

Most people don't realize that you don't have to be all that accurate when doing Celestial Navigation, since you're generally in open ocean when you're really using it...and being off by a mile  or four isn't all that important when it comes right down to it...when you're talking about hundreds or thousands of miles.  The more accurate you can be the better, but you don't NEED pinpoint accuracy to get to land most of the time.

If you can see land, having charts and an idea of where you are is important, but if you know where you are to the nearest five miles or so, the coastline will generally tell you exactly where you are—provided your coastal pilotage skills are up to the task.

[Bill NH]

How hard could it be to take a sight twice a day??? what else are you going to be doing on a 30 day passage :)

Actually you should be taking at least three sights for a minimal noon position, two morning lines to advance and the noon sight.  The reason for a third line is that two lines will always cross somewhere, but you have no clue about the precision of your fix.  With three lines you either get a pinwheel (where all 3 lines intersect in the same place) or a triangle.  The pinwheel you can be confident in, while the bigger the triangle the less accurate the final fix.  It's a good check on the math as well as the actual sights.

[dnice]

Just for fun...

Yves is great, he cracks me up  ;D

Sextant video

[Frank]

I like Yves in the cape horn video wearing the baggy purple bib shorts......just too darn cool  ;) I guess no one can see you out there...thank goodness. He is a fine sailor and inventer ...ya gotta give him that.

[CapnK]

Awesome video clip. :) First time I have heard Yves speak. ;D Grog!