Stadiometer woes

[JBHemlock]

Most of my time playing this game in the past has been distinctly casual on the torpedo side. I've enjoyed maneuvering the sub, dealing with escorts, etc. But, masochist that I am, I've turned my sights on manual targeting.


I've been playing through the easy manual targeting scenario in sub school, and I think I have a handle on the basics. I can plot my target's course, estimate speed, etc, and get hits on it. However, getting a true M.O.T. hit has eluded me, and I think it's coming down to my inability to estimate range.


I did a comparison where I marked my target on a map and used the compass to estimate range, and then compared it with what I'm seeing from the stadiometer. The stadiometer consistently is giving me a range that's somewhere between 10-25% higher than what I'm estimating with a compass, and I'm not sure what I'm doing wrong. I've sent the target id to the TDC, and I'm using the stadiometer to put my target's waterline on the top of its mast, so it should be pretty foolproof, right?


Here's an image of what I'm doing, including the ship id book page. Can anyone see where I'm going wrong with this?