Making a Viking Sun Compass

[Stringmaker]

As it comes under navigation I hope this thread fits here, but please move if it doesn't.

This is an amusing read but also very simple and informative:

"Imagine the situation - you're due to go on a raid tomorrow, but Bjorn Hammersson won your lodestone in a game of hnefetafl last night. No magnetic lodestone, nothing to indicate North when you're out of sight of land. How are you going to find your way at sea?"

"Spend the day near your sun compass, doing useful things to prepare for your raid (mending sails, sharpening swords, doing careful stretching exercises so you don't pull a muscle during an important ravish, you know the kind of thing)."

http://www.instructables.com/id/Make-a-Viking-Sun-Compass/step2/Calibrate-your-sun-compass/

Well worth a few minutes of your time I think.

 

[Wayland]

I regularly demonstrate these to kids in schools.

Brilliantly simple tool and on a long voyage the directional error that creeps in due to the Sun's changing altitude, self cancels, because the mornings deflection is exactly the opposite of the afternoons deflection.

Important to have a way of ensuring the gnomon is vertical though.

 

[Dave]

Didnt they use some sort of sun stone as well?

 

[boatman]

Reference to changes in the Sun's altitude, the Vikings navigated by that altitude. Thus to get somewhere from Norway if they knew the Sun's altitude at their destination they would sail North or South along the coast until reaching the point where the Sun's altitude was the same and then sail along the line of latitude.

I believe that they would have used all methods available to them so it is quite possible that the "Sun compass" also indicated noon so that estimates of the angle of the Sun's altitude could be made. Of course the "noon" on a moving Viking ship changed according to longitude.

Incidentally I can't make a "sunstone" work to find the Sun on a cloudy day as they were supposed to do, has anyone been able to?

 

[Jared]

Haven't tried but remember seeing this

http://albert.lefloch.over-blog.com/article-viking-sunstone-87883291.html

A wooden instrument to rotate the sunstone and indicates the direction. Shame there isn't any plans for the device.

The academic paper on using sunstones is here http://rspa.royalsocietypublishing.org/content/468/2139/671.full.pdf+html

 

[Stringmaker]

I regularly demonstrate these to kids in schools.

Brilliantly simple tool and on a long voyage the directional error that creeps in due to the Sun's changing altitude, self cancels, because the mornings deflection is exactly the opposite of the afternoons deflection.

Important to have a way of ensuring the gnomon is vertical though.

The best tools are very often the simplest ones; I just liked the tounge in cheek way he wrote it up.

 

[Wayland]

Didnt they use some sort of sun stone as well?

There are some later Medieval references but much less evidence for use by the Vikings so far.

I do mention them in my talks for completeness, but I wonder how effective they would have been compared to good old fashioned seamanship.

I suspect they may have been a lot more useful for calming a nervous crew though. "Don't worry, I know where we're going because I have this magic stone" sort of thing.