Screw Turns

[divo 637]

Does anyone know if the propeller rotation is properly modeled in the game. So if the contact speeds up do the sounds you hear on sonar also speed up. I'm working on ways to get at speed and using a TPK ratio you can figure out speed if the shaft rotation is modeled.

If you get a good speed on a contact you can do the turn count and work backwards to the multiplier.

I use an old trick that they used on the USS Tang. Dick O'Kane bought a metronome and the sonar operater would match the blade count to the beat on the metronome and they could read the turns off of the scale on the metronome. My daughter takes piano so we have a small electronic metronome that works great at this. I just need to figure out if the model is even implemented or if the sounds are always the same.

[SteamWake]

Someone had actually worked this out for SH3.

Search around there for some hints :up:

[divo 637]

thanks, I assume then that this is implement in SH4 like in SH3 so that if we know the multiplier we can use the turns to get speed?

[raduz]

Does anyone know if the propeller rotation is properly modeled in the game. So if the contact speeds up do the sounds you hear on sonar also speed up. I'm working on ways to get at speed and using a TPK ratio you can figure out speed if the shaft rotation is modeled.

If you get a good speed on a contact you can do the turn count and work backwards to the multiplier.

I use an old trick that they used on the USS Tang. Dick O'Kane bought a metronome and the sonar operater would match the blade count to the beat on the metronome and they could read the turns off of the scale on the metronome. My daughter takes piano so we have a small electronic metronome that works great at this. I just need to figure out if the model is even implemented or if the sounds are always the same.

The propeller pitch is not modeled in SH4, nor it is in SH3. actually, it is modeled but only in certain limits.

The RPM can be adjusted in ships .sim file and indeed, if you check visually, you can see the screws turning according to the RPM you set. You can set freely any RPM, and it will always correspond to the real turn count. However, there is a problem with the hydrophone sound. The sound of screws you hear on hydrophone is definied by several sound files but the most imporant (that determinates the turn count) is "propeler_4_hyd.wav" (for merchants) and "propeler_5_hyd.wav" (for warships).

This file is "customized" by game according to the real turn count and can be shortened or extended. BUT - this "customization" is limited. The merchants can only have RPM from 21 to 47 and the warships have the double RPM rate (42-94). So if the merchants screws are doing 15 RPMs (that you can clearly see with the free camera), you wil still hear 21. The same goes for turns up to 47. I tried to modify the propeler_4_hyd file in order to get larger "RPM area" but I discovered that the length of the sound file is not important. The game is set so that this file would be extended/shortened of some 40 percent (my guess), no matter how long it is.

One more thing. If you set the RPM to 25 and the max.speed to 25 knots, the ship will do 25 RPMs at 25 knots. But that doesnt mean 1 knot = 1 RPM. The RPM is reduced progressively as the speed drops, but I dont know how is this done. And most likely, a ship with the RPM of 25/max.speed of 25 knots will do 1-7 knots at 21 RPMs. (The speeds from 1 to 7 knots will share the RPM of 21). And if you set the RPM to 57, you will still hear 47. So we are limited up and down...

Till now, I didnt find out any way how to set the TPK rate, although I wish very much.This must be hard coded and I dont think we can go better without the SDK... The only thing that can be actually done is to fiddle with RPM/max.speed so that the RPM would be "divided" between 21 - 47 RPMs. According to my tests, the ideal ratio of the max.speed and the RPM is 13 knots/47 RPM. In such circumstances, each knot will have a specific RPM. However, as there are merchants with a max.speed of more then 13 knots, we are done.

I would appreciate any suggestions.

[nattydread]

The things is, the skipper shouldnt be determining speed based on screw turns anyway...the sonar crewmen should be doing that. So even if the actual sounds dont match, the sonar crewmen should be able to estimate speed based on experience, skill and sound conditions on their own.

Its amazing that so many crew functions were left out. You'd think they'd have had more time hammer out relativly more fire control functionality over SHIII considering they werent totally building from scratch.

[divo 637]

Thanks Raduz! That helps explain this issue.

Nattydread, i agree. There are some basic functions that would really help. Having a plotter plot bearling lines to the target on the map would be helpful. Say every 30 sec. Or same for sonar bearings (you can get full solutions based on sonar bearings alone).

Or just someone to plot the bearings I take on the scope.

It is tough to be the captain, run the geo plot, work the TDC etc. I don't want them to plot all the targets on the map. Just the info I am giving on each of the contacts.