It seems Noonan was involved to some extent with an Aussie who was possibly one of the best aerial and nautical navigators in the world at the time. Gatty was an expert in use of the Pelorus and designed (along with Weims I believe) an excellent Drift Sight/Meter.
Having used a primitive form of Pelorus for many years without realising what I was using, both in marine and terrestrial navigation, I, like many people found myself automatically setting one up using reference points in a cockpit when navigating.
And so to drift.
I can see where the pelorus listed in the Luke Field Inventory would be very useful for Fred Noonan when flying over land. I can see that it 'could' be useful flying over water, especially if there were recognisable islands in sight. Mu Hand Bearing Compasses served a similar purpose. Check object Left, Check object Right, draw a line at the angle to each object and you 'might' be where the lines cross.
However, the Pelorus listed in the Luke Field Inventory is a Mark IIB. The information about the IIB says in part:
A Pelorus Drift Sight is designed to function either as a Pelorus, for taking bearings on objects,
or for improving dead reckoning aircraft navigation by measuring the angle between the heading and the track of an airplane. (my pretty bits)
It consists of a small 'telescope' viewing vertically towards the ground, angled toward the direction of the aircraft. When viewing the ground through the scope while in flight, the navigator observes the travel of fixed objects across the lens. By rotating the scope on its base to align the path of these objects, the drift angle is determined by reading the location of the pointer on the base's scale. Once done, the course correction is calculated and communicated to the pilot.
I think I saw the operating Instructions for Fred's Pelorus in this post already, but here they are again, to confirm that both the Drift Meter Model D-270, and the Pelorus CAN be used over water. The Pelorus usually REQUIRES Smoke Bombs for that porpoise!
So the question about Drift Meters probably boils down to 'Was a Pelorus amongst the stuff left behind at the start of the second flight? In my opinion he would not have left Either the Pelorus OR the Drift Meter behind with so much water around.
It seems unlikely, especially as Fred Noonan was 'most likely' well versed in the use of both Drift Meter AND Pelorus over water, and there was 'a possibility' he might have to navigate over water at some time.
In BOTH cases the instrument must be able to be used from BOTH sides of the cockpit. And the Luke Field Inventory lists a 'spare' base for both Pelorus AND Drift Meter.
However the bases are NOT 'Spare'... There are Two Bases for Each instrument.
*** RossD E D I T ***
I should not get on board TIGHAR Forum when I am ill or tired ! (which is most of the time) And I apologise that my mind and fingers don;t always work in concert.
What the sentence abouve SHOULD have said is:
In BOTH cases the instrument must be able to be used from BOTH sides of the AEROPLANE.
- (my Bad) I had been looking at the Nav manuals and stuff for a single or 2 place aircraft with no cabin. You can use a Pelorus while sitting on a horse. All you have to be able to do is look at stuff.
Please forgive me for not being quite up to date with this topic after all these years. I'm sure we discussed all this in the old days, but sometimes things are lost in the mix. So my apologies if I'm doubling up on old info..
Th WOMBAT
This seems to be the Pelorus type that Fred had:
This one is Early WWII, so a couple of years might not have changed it much:
https://aeroantique.com/products/drift-sights-mk-ii-b-pelorus-wwii-us-navy-aircraft?variant=46712079050And the 'How To' guide for Boy Scouts and other adventurers..
https://cdn.shopify.com/s/files/1/1343/9895/files/Drift_Sight_Mk_IIB_from_US_Navy_Navigation_Manual.pdf?2830330365304809310I know this type has already been linked. The Type Lindbergh tried but found impossible 'in his aeroplane'. :
https://timeandnavigation.si.edu/multimedia-asset/pioneer-drift-meterhttps://www.wy2.org/maint/speed-and-drift.php