GPS is a wonderful technology. It allows you to glance at your display and see exactly where you are! Chart plotters are even better, granting you the ability to see not only your coordinates, but your live position on a digital chart. Snaking your way through coral reefs at night becomes easy as driving down a country road, just follow the map and keep your digital representation on the map in the middle of your digital representation of a road and hope that there is no new debris in the way that you could bump into.
So we all agree relying too heavily on GPS is a bad thing and that it doesn’t replace proper seamanship and navigation?
If a nuclear bomb detonates in space at the start of World War III or if lightning strikes your mast (both equally probable events), the GPS as well as all your electronic navigational equipment will be toast! This is where backups come into play.
The most reliable and time tested backup is the classic sextant. You see them in movies where they try to make the captain look extra “shippy” by having him look out into the distance and say “Aye, we be nearin’ the coast”. The sextants they show in movies are in fact movie props, but they look like the bronze masterpieces created by expert craftsmen.
For the price of a small boat, you can have a piece of navigational history! You will have an expensive antique that has stood the test of time and is incredibly heavy to hold while you try to sight the sun to find your position.
For that price, you could buy yourself a fancy Raymarine chartplotter and be able to snake your way through narrow waterways on the giant display screen!
What about those significantly less expensive plastic sextants? Are they any good? What are the problems with them? Why are they so much cheaper than the bronze models?
In 2020, we crossed the Atlantic from Cape Verde to Suriname (East to West crossing) using a plastic sextant as our guide. We turned off the GPS and primarily used noon sights to find our way across the ocean.
The plastic sextant did the trick! It accurately records the height of the sun in the sky and is easy to hold while you are doing a reading thanks to its lightweight plastic design.
As for concerns that the plastic sextants are “cheap”: They are a delicate measuring device that needs to be cared for. If you feel that a $2000 bronze sextant needs to live in its case, safely stowed inside the boat, why shouldn’t you do the same thing for your $300 plastic sextant?
We keep our sextant in a specially made box, safely stowed in the cabin away from strong sunlight. If I left it out on the deck, the heat from the sun could distort the arc of the sextant and ruin it; but why would you do that? Take care of your sextant and treat it as a priceless piece of equipment while you are sailing because regardless of the price, all sextants are irreplaceable out at sea.
Some people feel that you get what you pay for and if you paid more, it’s naturally better! Bronze is an expensive metal to make things out of compared to plastic, which is why the bronze units are so much more expensive! A solid gold sextant would be the most expensive option of all, but being made of gold would not make it any better than a bronze or plastic unit. The second part of the cost is the act of making the unit calibrated. Regardless of the material, calibrating the unit is an exacting task which takes money to do, and the result is a precise measuring device made out of different materials. The major cost difference is in the material that the measurements are produced on.
For a reliable backup to navigational electronics, we trust our plastic sextant! It does the job, is light weight, and won’t corrode in the marine environment. If it does die a watery or heat related death, it can also be replaced at an affordable rate compared to a more expensive unit.
