Something that occurred to me whilst trying to work out where the top of a mast was, was that if the relative dimensions are accurate in the RM I might be able to guesstimate the funnel or bridge height - also if I got a masthead reading in good light, that I was happy with, then I could use the same procedure for calculating AoB to get a height for the bridge or a funnel, for use in poor light. I'll start looking into that directly. What do you think? is that going to be expecting too much?

No that's not too much to expect. If the optical view is corrected in-game. When corrected, the ability to measure accurately becomes much more effective. In real life, the subs WWII Telemeters (the hash marks on the lens) would subtend approximately 52.5 feet if the object was 1000 yards distance from the lens. One degree of Height/Length at 1000 yards distance is 52.5 ft. The Telemeters are one degree apart. When you have 32 of them (spaced equally apart), and you can count 16 degrees to the edge of view (if the periscope bearing is moved to the edge), and the objects you're viewing is 1000 yard distance from the lens.......the optical world is right. That's how OTC corrects the world view, by correcting the viewable distance between the center of the lens, to the edge of the lens, with objects at 1000 yard distances. There should be exactly 16 degrees of bearing length between the two points.

If an estimated height was 100 feet for a particular spot on the target object, and the measurement in Telemeters below this point was half a Telemeter @ 1000 yard range distance. The spot in question would be estimated to be 74 ft in height. It's how things were figured when only one estimated height measurement was known. I'm sure every Captain remade his estimates of height when he realized his range isn't correct after an errant shot was made and all other possibilities were reasonably accurate.

My plan is to make a better Recognition Manual with several different height measurements on key spots of each ship. This way a player can choose the best place to make a measurement. The games process of inputting dimensions will have to be changed since the Attack Data Tool doesn't allow for specific height/length dimensions. Also, the Stadimeter only allows one measurement to be entered for each target. But, this has been in the back of my mind for quite some time. It's quite do able, but it takes time.

Let me see if I've got this right. The scope is at low power and the masthead is 100 ft high - A whisker over 1 3/4 increments tall, and the top of the bridge is half a telemeter increment below it. The target is 1000 yards away so we can call the bridge height 74 feet?

That's interesting. I suspect that as long as you have a positive ID and a good idea of the AoB that would work pretty well - Something I just found out though is that ID'ing the target correctly seems to be pretty vital. I picked up a Hakusika Maru and wrongly ID'd it as a Biyo Maru - height and draft are much the same but length is very different, which had the result of throwing my AoB estimates out. I didn't question the ID, and I didn't use the ID Ship feature - I assumed my estimate of target speed was wrong. Long story short - missed with three torpedoes - sent a further two out with a correction to the gyro angle and hit it.

It's interesting to note that if I'd set up for a DoK shoot, the errors I'd made wouldn't have mattered, and if I'd paid more attention to detail I'd have known my data were being skewed. - In my defence, the discrepancies I saw with the data weren't huge, but they turned out to be enough, since they prompted me to change the target speed I had set and that and the incorrect AoB, did the trick.....

To be honest I see little point in turning the PK on for a single ship, but I'm trying to use it more so's I'm good when I need it.

No, at low power magnification a single degree is as below.....52.5 ft = 1 degree @ 1000 yards distance. If a mast height was 100 ft tall, at low power magnification, the telemeter increment would be a wisker under 2 full degree marks. Two full degree marks only covers 105 feet. It's much closer to two full degree marks than saying its a bit over 1 3/4. Sounds like I'm spliting hairs but it will make a difference.


http://i175.photobucket.com/albums/w...psa52aa6ec.jpg


You are correct to think that if the bridge top is just half a telemeter distance lower then the mast top, then its measurement is 74 ft tall. Its just that one quarter taken from 2 full telemeters is a shade under 1 3/4 tall @ 1000 yards distance.

Yes - as it happens I'd mis-copied the telemeter index mark by about 1/16" - fixed it now :) Thanks

The beauty of the American periscope using a 1.5x magnification at low power, compared to 6x at high power.....with a 32 degree optical field-of-view......is the different magnifications can easily be multiplied or divided into each other, yet still come out with a reasonably accurate measurement.

The Germans didn't have this symentry with their optics. It's probably why SH4 became such a "bastard child" compared to the other Silent Hunter series games from UbiSoft. I don't know if SHIII and SHV has the same problem in rendering their optics correctly as SH4, but they really screwed the pooch for the American Fleet Boat in the Pacific.

I have to ask - was that a design feature or a happy accident? Also I realise I'm kind of stereotyping here, but that's the kind of detail I'd expect a German engineer to come up with

For all I know we may have had a German defector figuring out the authentic American optics. Anyway, I'm guessing it was no accident.

Yeah - that was badly phrased - Of course it wasn't a coincidence. Thing is it's a pure design issue - there's no technology involved per se, so I'm surprised that U-Boats didn't adopt it, but since I know nothing about periscopes that's not saying much. Was there any advantage to their design?

The German periscopes were similar to the American versions in regards to the magnifications used, however the FoV were different. Here's an excerpt of a British intelligence report for the captured U-Boat U-570:

Optical Arrangement

Magnifications: 1.5x low power / 6x high power
Angular field : 38° low power / 9° high power
Exit pupil: 3.5 mm. / 3.5 mm

8. The top reflector gives an elevation movement of from - 15° to + 20°.
9. The optical performance in both powers is satisfactory.


Since the American version had an angular field of view of 32 degrees for low power, 8 degrees for high power, it seems to lend itself better to correspond to each power. Perhaps it's due to the fact that the American unit of measurements can easily focus on fractions (two quarters = a half. Or three 1/3's = a whole) better than the metric system? I don't know, maybe I'm showing my ignorance! :88)

I chuckled at the thought that you might be showing your ignorance. I wonder what that makes me? The metric system has a lot to recommend it, but as you point out, it doesn't handle fractions very well - basically it only has 1/10 and powers thereof. I was thinking about how the omnimeter has changed the way I play, and how tools in general seem to change the way we think about a task as much as the way we perform it, so it seems a perfectly reasonable idea that an engineer brought up thinking in tenths, simply wouldn't think of making a scale that worked as a multiple of 4.

If I'd had this to play with in 1975 I wouldn't suck at maths the way I currently do. - we're going about education totally the wrong way.....

Also the report looks pretty interesting - Bookmarked.....