Slide Rule Targeting for SHIII/SHIV

[Puster Bill]

Originally Posted by ronbrewer

Thanks for the excellent instructions. I have a question about the two observations. Does the sub have to be at a stop or can you creep along at around 2-3 knots in between the two measurements? I'm just curious if I need to be on the surface or can remain at periscope depth (which would require some form of movement to maintain depth).

Thanks,
Ron

I find that if you are creeping at steerage, ie. 1 to 2 knots, it doesn't introduce enough error to matter as long as you aren't taking very long shots.

If you were going faster than that, it would introduce more error.

[jmr]

Slide rules and whiz wheels rule! Here's some I made from various posts on these forums.

Kin Ronoff's Range Calculator Mark 3B and Course Calculator Mark4B



Target course calculator and nasmith director



Banjo

[Puster Bill]

Originally Posted by jmr

Target course calculator and nasmith director

I adapted the instructions for that wheel (first picture in my post) to a linear slide rule. I did find that he uses 5.70 for converting from Yards per Second to Knots, which is incorrect. It's actually about 5.64, which I round down to 5.6.

[jmr]

Originally Posted by Puster Bill

I adapted the instructions for that wheel (first picture in my post) to a linear slide rule. I did find that he uses 5.70 for converting from Yards per Second to Knots, which is incorrect. It's actually about 5.64, which I round down to 5.6.

Yeah the graduations are a bit sloppy as well which is why I hardly used that wheel. I'm going to have to shopping around my area antique stores for a slide rule. I made my own from this page but I'd like to have the real deal and not a laminated card stock one

[Puster Bill]

Originally Posted by jmr

Yeah the graduations are a bit sloppy as well which is why I hardly used that wheel. I'm going to have to shopping around my area antique stores for a slide rule. I made my own from this page but I'd like to have the real deal and not a laminated card stock one

Yep. That's why I went looking for one.

Although, I think I am going to have my father build a wooden, brass, or acrylic base for that Yokota Log-Log rule. He's handier at that kind of stuff than I am.

I built one out of cardboard, and I love it, I just want a sturdier one.

Damn, this slide rule thing can be addictive!

[Jace11]

A slide rule in game map tool would be rather useful methinks...

[Puster Bill]

OK, I built the circular slide rule at the sphere site. Here is the whole thing:



And here is a close-up:


One piece of advice: If I were going to do it again, I would take a highlighter and highlight the S scale before I laminated it. As it is, it kind of gets lost in the other scales.

[don1reed]

Good job, Bill. It's good to see you youngsters keeping the math traditions alive.

I built that circular sliderule from "Sphere" also. I highly recommend it, especially for those who get confused when obligated to move the slide on a 10" model due to answers appearing off scale--less cursor movement.

One of these days, I'm hoping, one of these computer whiz-kids emulates a Bearing Rate Computer (whiz-wheel), that would really be nice.

Cheers

[Gangrene]

Or, unless you had one of these little bad boys!!!