A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: David Smith
Date: 2017 Jan 23, 23:48 -0800
Many thanks to all those who answered my questions relating to an upcoming container ship voyage. I would like to reply in the order of the posts.
Brad, your idea of a plastic sextant is absolutely brilliant. I am anticipating the problem of one of the crew asking to use my sextant. I’d rather lend my tooth brush, for once the sextant is dropped or the index arm bent, the whole purpose of the voyage is lost. A refusal, however polite, would not help to build a harmonious friendship.
I fully agree with taking a hardcopy of an almanac – I intend to print out the daily pages for the period of the voyage plus the increments and corrections pages. I’ve discovered that looking up increments and corrections is easier from the printed page than trawling through .pdf documents. I’m still quite relaxed on having the majority of my reading material on the computer. With a large memory card in my ‘phablet’ (a phone-tablet hybrid) and yet another copy in a USB stick, I am pretty confident that things will be OK. If the Macbook fails, then the phablet will come into use, if that fails then it will be a case of going ashore at the next port to buy something that I can plug the USB stick into.
Frank. Thanks for your advice. The information that I presently have is that Internet is not available, but limited use of the Captain’s email service may be allowed. Near my home is the port of Napier – I often see crew members walking to the Seaman’s Mission for the purpose of sending and receiving emails or making a phone call home. However, I fully agree with you, this might all change very quickly. As I write this, I am connected to the Internet over an old 3g cellphone network, the cost is minimal and speed quite acceptable. One day soon, container terminals might be flooded with cheap high speed 5g networks, extended range wireless and, who knows, satellite networks might also become affordable to use. I’ve been thinking about the merits of International data sim cards to use when close the coast – I believe the cost is somewhere about $50 a GB.
Bill. I remember that about 4 years ago you told the NavList members about your trip across the Pacific. This encouraged me to plan to do the same! It appears you had a great trip with just the minimum of equipment.
Will. It would be great to have a few small scale charts. I have so far been unable to find any pilot charts or ocean charts listed in the local chart agencies, but the website https://sailingaroundtheworld.wordpress.com/2014/10/30/ looks very promising.
One thing that I am considering is how many plotting sheets are enough? Could a plotting sheet be made on an erasable whiteboard and would the whiteboard maker tips be fine enough? I guess 4 sheets per day would be sufficient – dawn sights, running fix, evening sights and a supplementary set of sights. 40 years ago I sailed on merchant ships as a Radio Officer. Celestial navigation and dead-reckoning were the principle means of navigation when more than forty miles away from the coast, but I can’t remember ever seeing a plotting sheet in use – I intend to ask some of the navigating officers whom I sailed with how they did sight reduction and plotting.
Greg. I’ve followed your advice several times in the past and really appreciate the time you have put in making your list. Not long ago there was a discussion on NavList as to the importance of having a second digital watch that is adjusted to UT. I ordered the watch you recommended and it fixes on the scope of the sextant just perfectly. I note that it does gain about a second per month – this is a useful feature as it encourages the use of a rate book – just like was used with mechanical chronometers before the digital age. I do remember deck officers using stop-watches – they would stride through the chart room, stop-watch and sextant in hand, peer at the chronometer and ‘click’. Some mates trusted their counting – you could hear them coming in off the bridge wing – “one thousand and six, one thousand and seven, one thousand and eight…………”.
Number 8 in your list is a compact travel shortwave radio. What is the main purpose of carrying a shortwave receiver? I’ve been a shortwave listener and a radio amateur since I was a teenager, but find very little interesting to listen to on the bands these days. The chances of hearing WWV time signals in the Indian Ocean on a compact receiver would be limited. I guess these days ships have communal aerial (antenna) systems. When I was at sea, only passenger ships had communal aerial (antenna) systems – there was a huge rack of valves (tubes), cathode follower amplifiers – one for each cabin. On tankers and cargo ships, the crew would dangle wires out of the portholes – which had two major disadvantages, one was the porthole would leak rain or sea water over their bunks and secondly the aerials (antennas) would alter the Direction Finder calibration curve.
Number 16 on your list is binoculars. Would the monocular scope from the sextant be an adequate substitute?
Number 17 on your list – determining an accurate height of eye is one thing that a deck officer might have to assist with. The height from the load line to the bridge wing or monkey island can be obtained from the ship’s plans. The height from the sea to the load line, for that particular segment of the voyage, will either have to be observed from the wharf or obtained from the ship’s log.
Noell. Having a list of selected stars from HO 249 is a great idea. I was camping at a beach just before Christmas (it is summer down here) and when preparing for evening sights found it tricky with the star-finder to work out which stars (or planet) I would shoot first. Selected stars from HO 249 made it easy. I guess some of the star-finder apps would do the same job.
Sean. Another great idea – a chart plotter. Until about 5 years ago I crewed on an offshore yacht. I used to enjoy the chart work, but then an HP laptop was screwed to the chart table and the paper charts were confined to the chart drawer. I went through all the drama of interfacing the GPS and the AIS to the laptop and would enjoy doing the exercise again. This time it will be using a MacBook and either a USB GPS or a cheap Bluetooth GPS. I understand that some of these USB or Bluetooth devices can be configured for the Glonass or Galileo systems – this could be interesting. This device will duplicate the GPS in my Samsung phone. Many thanks for the introduction to OpenCPN and Andrés’ Navigational Algorithms.
Andrés - many thanks for your post. I am presently away from home and using a MacBook. Tomorrow I’ll download your software on a PC and am very much looking forward to using it.
Michael. Traverse tables – great idea. This would be a new subject for me – in the RYA Yachtmaster courses, traverse tables didn’t even get a mention!
Again, many thanks to all of you for the most valuable advice.