[Pisces]

You don't have to wait for a specific width of 10.5 before you do it. You measure whatever it shows and use that in the procedure. Just turn the scope to get the bow or stern on an easy mark to measure from. Like 5 left here. Then 5.5 on the opposite side ( right) adds up to 10.5.

[ideally #2 and #6 are done in quick succession with minimal delay. You can measure size first, write it down, then hussle the ring around to get the result. Keep the periscope pointed in roughly the same direction as you do it.]

1: identify, look up ship length and height in ID book.
2: Measure height in scope
3: set measured height at the 12 o'clock position of the most inside ring of the RAOBF wheel.
4: read off range opposite the real height on the most outer scale.
5: Drag that point to opposite the real target length.
6: Measure width in scope as mentioned above.
7: Then locate the observed width on the innerscale of the middle wheel, and read opposite of that the calculated AOB. (It shows the same value if it is moving away. So if it does, then use 180-AOB instead. If it is closing use AOB as-is.)