Invoking the presence of a second sextant/octant on board the Electra weakens the argument for a Gardner landing. The most likely “sextant” box to be found on the island that could be associated with Fred Noonan is the one he borrowed from Harry Manning (see
http://tighar.org/wiki/File:Noonan_Octant_Receipt.jpg). I think it safe to assume that FN took that particular octant on the Lae-Howland flight. I’m trying to find out more about that box. Inquiries to the Naval Observatory Records department regarding the box reported to have been found on Gardner haven’t turned up anything, so I’m trying a different approach, asking them what records of Manning’s instrument may be available, if any. GL believes the instrument was an “A5” style instrument, which would be reasonable assumption for 1937. However, we need to keep in mind that this is an assumption. We also need to keep in mind another assumption – that the box that Harry Manning’s octant was in wouldn’t have been confused for a “sextant” box. We know from existing examples of Octant boxes at the Smithsonian that some octants of the era used low-profile boxes typical of traditional marine sextants, and others used tall profile boxes. Tall boxes were becoming the normal style for Aircraft Octants just before the year of the flight. It is possible, if unlikely, that the box that Manning’s sextant was stored in was a low profile “sextant box” like the one found on Gardner. If we discover that Manning’s box doesn’t fit the Gardner box description, then the source of the Gardner box will remain a mystery, and the TIGHAR hypothesis will not be supported by that approach. If Manning’s box matches the Gardner box, then the case for AE/FN landing on Gardner is supported.
At this point we cannot say definitively what style of Octant box was on board the Electra. We may be able to say what sort of box Harry Manning’s Octant had, if Naval Observatory records are available. Some day we might even be able to say more about the box found on Gardner, if the numbers on it turn up in some record.