[Milsurplus] ATB + ARB = ?

[Hue Miller]

Mike Hanz's photos show the ARB-ATB in the "classic" command set configuration,
in fact replacing THE "Command Sets". Other photos of PBY boats show the operator
desk as having both and ARB and an RU, and the ARB has the local tuning adaptor. 
I don't know how these were used, but i suspect basically the same way, with the
RU being "well-enough" suited to CW reception to be used solely by the RadioOp 
with the GO for position reports. 
 
Re Mr. Hanz's photo- here is something i wonder: what if you flew to an island
with a different HF tower voice frequency. What was the procedure for having
the ARB+ATB retuned to that frequency? I do NOT think this was an impossible
situation, judging from the Pacific area facilities books i have looked at.
-Hue Miller