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TorpX · 12-30-10, 09:03 PM

This dead reckoning business has proved to be harder than I anticipated. I have been playing around with the school mission to try to see what might be done about it.

First, as measured by the in-game ruler, the degrees of lat. are 64.7nm. The deg. of lon. are also 64.7nm. The meridians do not converge at all, end of story. In other words the earth is flat. At least, this is consistant.
The speeds given by the HUD knotmeter are too high. In a S-18 class boat going standard gives a reading of ~10.4 when you are moving 10.0 kt. Figures for other speeds were similer. This includes submerged movement. While not entirely consistant, I would suggest multiplying the displayed speed by .95. I did not use the helm position knotmeter as it gives even higher values: At std, the helm dial would be about 10.7 or 10.8, the HUD dial would be about 10.4, and the actual speed 10.0.
The HUD compass is very hard to read, and in my set up, at least, seemed to be off a good 2 degrees. The heading, as stated by the crew, seemed to be accurate to within a degree. I experimented with three ways to get the most accurate heading. None of them were very satisfactory. Using the HUD dial was terrible, using short waypoint lines did not work well, even putting the boat on a grid line and using the permanent protractor (a RFB thing, I guess) gave uneven results ( and would be extremely impractical anyway). All things considered, going by the crew statements, seems the best. A heading within .5 deg. is about the best you can hope for with the game as it is now.

Though few using cel-nav will be using the waypoints, I happened to observe some things that might be of interest. I found that the helmsman does not steer a constant heading between waypoints. If, for example, you put two wp's a long distance apart on the equator, say 120 or 240nm, go to high TC, then slow down to zoom in, you can find yourself 1 or 2 nm off course. As you near the next wp, increasing corrections would be made to the heading to reach it. This becomes more obvious, if you place a distant wp, then, after the rudder has reached 0, order the crew to steer a constant course, go to high TC, and see how far off you are as you pass by the wp. Evidently, the game designers didn't contemplate any need for precision here.

I should point out here, that I tabulated these figures in calm conditions. There were no wind or weather factors involved. Rough seas are bound to make speed estimates much harder.

All and all, I think the in game compass and nav tools leave a lot to be desired, but would like to hear from others. I presume Sh3 captains are, excuse the pun, in the same boat. I have some other ideas, but want to use all of this in the game some more.

12-30-10, 09:03 PM	#169
TorpX Silent Hunter Join Date: Sep 2010 Posts: 3,975 Downloads: 153 Uploads: 11	Dead Reckoning This dead reckoning business has proved to be harder than I anticipated. I have been playing around with the school mission to try to see what might be done about it. First, as measured by the in-game ruler, the degrees of lat. are 64.7nm. The deg. of lon. are also 64.7nm. The meridians do not converge at all, end of story. In other words the earth is flat. At least, this is consistant. The speeds given by the HUD knotmeter are too high. In a S-18 class boat going standard gives a reading of ~10.4 when you are moving 10.0 kt. Figures for other speeds were similer. This includes submerged movement. While not entirely consistant, I would suggest multiplying the displayed speed by .95. I did not use the helm position knotmeter as it gives even higher values: At std, the helm dial would be about 10.7 or 10.8, the HUD dial would be about 10.4, and the actual speed 10.0. The HUD compass is very hard to read, and in my set up, at least, seemed to be off a good 2 degrees. The heading, as stated by the crew, seemed to be accurate to within a degree. I experimented with three ways to get the most accurate heading. None of them were very satisfactory. Using the HUD dial was terrible, using short waypoint lines did not work well, even putting the boat on a grid line and using the permanent protractor (a RFB thing, I guess) gave uneven results ( and would be extremely impractical anyway). All things considered, going by the crew statements, seems the best. A heading within .5 deg. is about the best you can hope for with the game as it is now. Though few using cel-nav will be using the waypoints, I happened to observe some things that might be of interest. I found that the helmsman does not steer a constant heading between waypoints. If, for example, you put two wp's a long distance apart on the equator, say 120 or 240nm, go to high TC, then slow down to zoom in, you can find yourself 1 or 2 nm off course. As you near the next wp, increasing corrections would be made to the heading to reach it. This becomes more obvious, if you place a distant wp, then, after the rudder has reached 0, order the crew to steer a constant course, go to high TC, and see how far off you are as you pass by the wp. Evidently, the game designers didn't contemplate any need for precision here. I should point out here, that I tabulated these figures in calm conditions. There were no wind or weather factors involved. Rough seas are bound to make speed estimates much harder. All and all, I think the in game compass and nav tools leave a lot to be desired, but would like to hear from others. I presume Sh3 captains are, excuse the pun, in the same boat. I have some other ideas, but want to use all of this in the game some more.