Same years ago I invented the Bris Sextant as a backup. It’s a small cheap functional instrument. Its extremely accurate, much more so than the ordinary sextant because it uses a number of fixed angels instead of a continues scale, but like the ordinary sextant it needs accurate time to give you a fix.

Photo above Bris Sextant in my right hand the ordinary in the left.

Time can be lost due to lightning, if there is a fire onboard and you most abandon ship, and for many more reasons such as the unlikely event of our civilization braking down and the time signals stops.

Fortunately latitude can be found without time by observing the suns altitude at noon.

The chronometer was invented only after most of the world had been explored so most discoveries were done without synchronized time. Therefore the explorers could not find their longitude. The going was though. They overestimated how far they had gone. Their latitude they could check, but not their longitude, hence maps from that time show the world much fatter. See illustration below.

To find ones destination without synchronized, one has to sail north or south to the latitude of the desired destination, then sailing east or west, constantly sounding and with a sharp lockout until one arrived at the desired destination.

Of course I could get an ordinary sextant but they are complicated and prone to errors, so I thought if I could invent a small cheap functional sextant with a continues scale, but without moving parts it would be a good thing.

An other picture

Photo above the survival sextant with its continues scale and its cursor.

Me with the first experimental model. I used it to testi if the new principel worked. It did and does but its accuracy is good enough for survival use.

I will soon publish an explanation of its principle and how to you use her.

To be continued …

Regards Yrvind.