NavList:

Alex, love your comment!

I have two Coutinho-style sextants, a Plath still in its cool lightweight metal can-case (thus clearly intended to be an airborne instrument), and a Tamaya (Plath OEM) with the same style of AH. The latter is in an oak case, so presumably was intended for ship-borne use (a Japanese historian friend tells me it was likely meant to be used on a submarine - am told the low conning tower height made reliable horizon shots impractical in the choppy Pacific).

I also have two later-model Plath single-bubble AHs and a C&P AH, which of course were intended for marine use only as they were produced decades after bubble sextants became the norm in the air/

Holding level with the single-bubble AH is difficult enough, but finding and holding level in the two-bubble Coutinho reminds one of the old patting-your-head-while-rubbing-your-stomach joke.  Or more precisely, it is like trying to thread a needle while giggling.  And this is while standing on terra firma!

I thus cannot imagine the level of practice it must have taken to get a remotely accurate fix with a Coutinho-style AH from a Zeppelin. And doing the same from an open-cockpit plane of that era seems improbable in the extreme.

Little wonder that the design was quickly abandoned in favor of a proper bubble sextant...

-p