I have Bowditch Practical Navigators from 1800s.  1807, '39, '41, '54, 1916, '95, and 2003.  They list instruments and nav tools in which I am interested.  The Sector and Gunter scale are two math aids that provided skippers with logarithmic and trig scales to facilitate navigation. 

 If any of you have knowledge or references for these and other old world tools Id be pleased to discuss them.  Other tools might be the Gunter Quadrant, back-staff, octant, plane scale, full circle brass protractor and dividers, barometers, speed measuring devices, depth sounders, even their paper charts interest me ... How did they protect them from damage or rot?   

Everything used from the 1800s and earlier has my attention (no batteries)... i want to learn to use those old tools.  I was interested to find out that they used a depth sounding device made of glass tubing that was painted inside with a material that changed color so that as the water pressure at depth squeezed water further up the tube the depth could be recorded.... soooo cooool   ... Ay?

Those 1800s sailors were not as ignorant as I thought...  Maybe we dont give them enough credit... I know I didnt until I started reading those old Practical Navigators.

joe

Maybe this is funny; maybe not.  I think its at least humorous.

Why are Google and Bing listed as perpetual users of this forum???

I think it's NOAA that now provides free pdf charts of US waters.  There are other organizations providing free charts of many parts of the world - but for the life of me i cannot find a single free chart of Philippine waters.

The Philippines had been under direct US control since 1898.  The Pi was a strategic US outpost ever since and enjoyed US protection until the Japanese invasion, then again after WW-2.  Up until the US pulled out in the 1980s all sorts of US watercraft, military or otherwise, plied these waters.  Where are the charts???

Why PI charts are missing from the internet is beyond me.  US citizens paid for them with taxes... now they seem to have disappeared.  

Does anyone have a resource for free Philippine charts?

joe

My Astro IIIb and Davis mk3  were stolen in the US a number of years ago.  Who ever stole them probably wouldnt even know what they are let alone know how to use them.  I really cant afford one now and wouldn't trust a good deal on Ebay- even shipping would be cost prohibitive.      

I am in the hopes that one of you wealthy sailors (if there is such a thing) will have pity on a poor old expat sailor living on the economy in South-East Asia and perhaps donate a reasonable sextant.    

I currently practice taking observations with my own altitude creations; a back-staff-like carpenter's square and a modified 45 that acts like a Gunter quad.  As I mentioned to the forum admin I even made a few Bris sextants.  The carpenters square is not marked in degrees so I use the cm scales and  some trig to get the altitude.

I promise to the best of my ability the sextant will receive great care, and that any donated sextant will never be sold in my lifetime, and upon my death I will have my wife return the sextant to society by way of donation to a likely individual or school with the same stipulation (or perhaps returned to the donator).

Part 2...  I also need some info relative to the HP correction tables.  I could use it before but now I am a bit confused about how to use it properly.  I know what HP is, but the table is a bit confusing.  Perhaps the instructions are in a paper almanac, but my almanac was obtained from this forum's host site without it. 

Part 3...  Then there is the matter of a typical refraction error correction..  If refraction error is combined into the Sun altitude correction table, then why is there a separate refraction table?  Im a bit confused and worry that I am mis-reducing my Gunter observations.  I actually do pretty well, but I wonder if I can do better.  When taking a Gunter sun shot I usually use star alt correction or Ha+LLc-SD+-T/P.  There is no DIP or IC correction with the Gunter.

By the way - when using my Gunter like instrument I never look into the sun.  I drilled a small hole at the front which allows a few rays of light to project onto an aligned white card at the back where the image of the sun is centered... I then rotate the Gunter locking the weighted string onto the degree scale. I then instantly stop a stopwatch which has been coordinated to GMT (UTC).  I usually do best if i wait a minute or two for the string to center on a whole or half degree mark.  Of course I am not taking the observation in the wind or on a rocking boat - I might not then be so lucky with my accuracy... :)  Moon, planet, and star shots seem to work out pretty well although they are a bit more difficult to align on the Gunter.  One of these days Im going to make a marine astrolab.  Ive also been experimenting with permanently positioned mirrors in the tradition of the Bris... and developing some ideas on how to make a Bris act like a sextant or octant (bris glass is self aligning, unlike sextant mirrors)...  necessity IS the mother of invention.

Any help would be greatly appreciated.

Joe

TABLE 3- Conversion of Arc to Time from Pub. No. 249 has been replaced by a new one I made.  It has also been added into The Nautical Almanac for years 2018, 2019, 2020.

You can get it here too-

Conversion of Arc to Time


Following seas,

Johannes

For the past few days the USNO's Astronomy site, in its entirety, has been unreachable.   The links below are examples.

http://aa.usno.navy.mil/data/docs/celnavtable.php

or....

https://aa.usno.navy.mil/data/docs/celnavtable.php

None of the links from the address below work;

http://www.usno.navy.mil/USNO/astronomic...a-services

Has anyone here tried these links?

Clen

I've added a few pages to the 2018 and 2019 Nautical Almanac;

- 2018 and 2019 Moon Phases

- TABLE 3- Conversion of Arc to Time

Perhaps you'll find them useful?

As time permits The Nautical Almanac for the year 2020 will be updated with the same pages.

Thank you,

Johannes

Volvo Ocean Race yachtsman John Fisher 'lost at sea'

• 4 hours ago
  

What tools do you use when plotting?

Parallel rules?

Rolling Plotter?

Dividers?

Triangles?

Simple ruler?  (like BigBill uses here- https://youtu.be/gucO6eVtwVo?t=13m2s

...or just good guess and an erasure?

Isn't there an easier way to do plots?  There's gotta be!

Fred

Bundaberg rum made many funny advertisements and since this forum is mostly about nautical things here's a good one-

https://www.youtube.com/watch?v=N5Kf7QPLsvs


I'm a member of a yacht club that's very much like these mariners.  It's a wonderful club with all of the glorious notions of..."well, at least we tried."

Set anchor,

Paul