GWX + ARB WideGui Periscope RAOBF Tick Mark Question

[promitheas]

Hello once again. I managed to install the Arb WideGui 1920x1080 v0.4 mod last night, and today when in the convoy attack training mission I tried making an attack with the RAOBF I got a feeling my calculations where a quite bit off when I used the red tick marks that appear over the centre wires of the periscope when selecting the RAOBF.

I tried using the regular periscope tick marks (without the RAOBF selected) to count out my mast height and ship length, and I got a lot closer to the values from the nav map which I used to verify.

Here is a screenshot with the RAOBF and the red tick marks:
periscope_2.jpg

and here it is without the RAOBF (using these marks gave me more accurate values):
periscope_1.jpg

My question is this: is my method wrong, or do the red tick marks mean nothing in reality and I do actually need to use the regular periscope's tick marks?

Here is my method in detail:

1. Count ticks from waterline to top of tallest mast
2. Turn the middle wheel until that number on the top of the middle wheel is right at the top of the RAOBF (bearing 000 )
3. Look for actual mast height on outer wheel and see what middle-ring-top number aligns with it. Thats range when you multiply by 10
4. Line up range value found in previous step to actual ship length on outer wheel
5. Count marks across ship
6. AoB is the number on the inner wheel that matches with the number in the lower middle wheel corresponding to the number of tick marks across the ship
7. Line up vertical wire to bow of ship and start chronometer when it touches it. Stop chronometer when aft touches it
8. Set the middle top wheel number corresponding to how many seconds it took for the ship to cross, to the number on the outer wheel representing the actual ship length. Speed is given by where the right line (red line crossing the top and middle rings) touches the lower middle ring.

Cheatsheet for above method except for speed calculation

The speed calculation I got from this video:


Can anyone enlighten me on what I am doing wrong? I did get 3 torpedo hits, but they were quite a bit aft of where I was aiming.