Hello Again Andrew,

In answer to your first question, yes, it would be conceivably possible to take astro-observations through a periscope for purposes of position fixing. Whether or not this happened on U-boats, I cannot answer. I have heard that this was the case in some of the modern post WWII submarines. I think that one of the professional submariners on this forum - there must be at least one or two out there - would be in a better position to answer that question.

Another aside, there is such a thing as a "periscopic bubble sextant". I have one in my collection that was designed for long range bomber aircraft. During the war, air navigators used to sight the stars and sun through a perspex dome in the roof of the aircraft. With the advent of pressurized, high-altitude aircraft, this dome had a nasty habit of exploding outwards and in some cases (I have not been able to document any) the navigator was apparently sucked out through the hole. The periscopic sextant overcame this little problem. I've used these before and they are not easy to master from a pitching, yawing aircraft. It was a humbling experience for me.

I can't imgagine what it would be like in trying to take an observation though a submarine persicope even in relatively calm seas. Simple as it seems, the marine sextant is still the best non-electronic method of fixing one's position at sea.

I will check with an American friend of mine who is probably one of the world's foremost experts on artificial horizon and other sextants. If a periscopic submarine sextant ever existed, he'll know about it.

Commenting on your last paragraph, yes, those old navigators on both sides of the war were, for the most part, superb at their jobs. They had a feel for the sea in all of her moods and were well-steeped in the nuances of her behaviour.

Nowadays, these skills are being lost and replaced by GPS.

regards,

Robert Eno