NavList:

David Pike: The P3B Orion carried 2 navigators – 1 the Tacco ( Tactical Coordinator) and the other a navigator – on patrol or transits we shared navigation.

On patrol – typically daylight you were most likely in radar contact with some island in the pacific or the coast of NZ so sun/planets shots weren’t needed. Long transits – NZ to Hawaii; NZ to Australia; or deep South patrols or deep East patrols out into the Southern Pacific islands are very sparse – you only had the sun or planets. Or long 15 hours submarine patrols – Hawaii north up towards Bering – patrolling a sonobuoy field – radar off – 25,0000 feet ( only Astro was possible). Yes a 3 star fix could be calculated quickly no doubt – we all became skilled at that – but likely the ceiling of the Vulcan was different to the P3B Orion – certainly the tasking was.

The problem that the portable calculator solved – was the speed at which you could do a 3 star fix – when you had high cirrus or other cloud obscuring part of the shot. Also, with cloud about and below say 30,000 you were not sure you precomputed would work – or you hit turbulence – or something else that stuffed up a precomputed fix. I could look out the periscopic sextant – say NOW – and with cloud partially obscuring part of the 360 degree field select 3 stars approx. 120 apart or may be not – if part of the field obscured – shoot 2 or 3 stars within the visual field – and then back compute the shot. THAT WAS THE BEAUTY of the calculator. Further, with high cirrus you might not be able to quite find the stars you want – precomputing would give the exact dec and azimuth of the star – preset that on your sextant – and very dim stars were right there in the field on your sextant.

And another use other than the obvious was that planets could be seen during the day theoretically – precomputing them often put them smack bang in the middle of the periscopic sextant on time – when you couldn’t actually find them visually searching.

But ……. You were ALWAYS up to speed on manual calculations – just in case technology failed – it happened. When I was navigator and the taco was navigating he would always ask me to calculate a 3 star fix for him and shoot it – typically the task of the off duty navigator/taco.

Regards Howard G