[WIP] Improved Ship Physics

[TorpX]

As a serious SH player, problems with the game physics have always bothered me. I've been goofing around with some of the game files (the boat sim files), and have made what I consider a minor, but significant breakthrough. I couldn't really see anyway to improve the ship physics before now. (Of course, this doesn't mean that there aren't plenty of obstacles to realistic physics remaining.)

Now that I understand the sim file elements better, I am starting serious work on a mod for RFB that will improve ship acceleration, turning, and any other aspects that can be helped within this part of the game.

My intention is to finish a mod for the player subs in the near future, and later, if possible, one for the IJ/Allied ships. The chief difficulty in the later is, apart from the number of ships, the difficulty of testing them. Without having playable ships that have a helm, knotmeter and all, I'm not sure how best to go about this.



Also, I have little data as to what the turning radii, of WWII subs and ships should be. If anyone has any information along these lines please don't hesitate to contribute.


TorpX

[Sailor Steve]

I can help with many of the surface ships. The subs I don't know.

Mark me down as watching, waiting and hoping.

[TorpX]

Thanks Steve. If you could post or PM me what you have for surface ships. Ideally, a good example of every major ship type: small merchant, medium merchant, large merchant, patrol craft, destroyer, light cruiser, etc., etc. I consider the merchants and the DD's to be most important. There is no hurry though. I want to finish the subs first.

The way I have been testing the subs is to push them to maximum speed, then put them into a 180 deg. turn. I record the minimum speed reached, and the diameter of the turning circle. I know enough now to be able to manipulate the speed drop off, and turning circle (at least within limits).

I did get some help with the subs, so I can proceed with this part.




Also, does anyone know exactly what the stats are for the S-18 and S-42 classes are? The values used in RFB and what I found in Wikipedia and Valor at Sea are very different, and I'm not sure what to use.

S-18
displacement 800/1062 tons
draft 15.1 ft.

RFB
displacement 944/1325 tons
draft 17.25 ft.



On a less happy note, I am vexed by the issue of submerged range (i.e. battery capacity), and recharging. The RFB file values indicate a range of 100 mi. @ 5 kts., but the boat won't go much beyond 40!
Putting in larger numbers does no good. I can decrease the range, but have no way to increase it. This aspect of the game seems to be broken, but maybe someone has some secret knowledge about this.
I've played around with different things to try to beat this problem, but have only gotten very odd and undesirable results.

For example, I tried setting the range to 30 mi. @ 30 kts. to trick the game into allowing a greater range. Using 50% of the battery allowed ~ 22 mi., slightly better than with the 30 mi. @ 5 kts. (17 mi.), but when I tried recharging the battery, I found I had to recharge it for 4 days to get a 9% increase! At this rate, it would be better to leave the batteries in port, and become a surface raider.

[cdp44]

My ship pack contains ships ranging from small armed fishing boat to New Mexico battleship, so if you need help testing those physics, I can help. No freighters or tankers at the moment, but I can whip something up if needed.

Here is the thread

http://www.subsim.com/radioroom/showthread.php?t=188786

Cdp44

[aanker]

Originally Posted by TorpX

Also, does anyone know exactly what the stats are for the S-18 and S-42 classes are? The values used in RFB and what I found in Wikipedia and Valor at Sea are very different, and I'm not sure what to use.

S-18
displacement 800/1062 tons
draft 15.1 ft.

RFB
displacement 944/1325 tons
draft 17.25 ft.
----------
On a less happy note, I am vexed by the issue of submerged range (i.e. battery capacity), and recharging. The RFB file values indicate a range of 100 mi. @ 5 kts., but the boat won't go much beyond 40!
Putting in larger numbers does no good. I can decrease the range, but have no way to increase it. This aspect of the game seems to be broken, but maybe someone has some secret knowledge about this.
I've played around with different things to try to beat this problem, but have only gotten very odd and undesirable results.

For example, I tried setting the range to 30 mi. @ 30 kts. to trick the game into allowing a greater range. Using 50% of the battery allowed ~ 22 mi., slightly better than with the 30 mi. @ 5 kts. (17 mi.), but when I tried recharging the battery, I found I had to recharge it for 4 days to get a 9% increase! At this rate, it would be better to leave the batteries in port, and become a surface raider.

You were/are at kickinbak right? Ducimus had a divine revelation - not a revolution - he liked to start those .... lol - just kidding... a divine inspiration and thought about battery life and fuel in a different light. The end result was to give a Propulsion expert special abilities in addition to changing the values in the sims.

Using tweaked sim settings I can sail submerged for over 98 nm @ 3 knots and run out of battery a little before the CO2 builds up to toxic levels a few hours later - around 48+/- hours.
I can also sail at the much used in real life, 'two-engine speed' - 15 knots - and have no problem getting 10,000 - 12,000 nm which is what they did in real life - I don't care what Wikipedia says. The 'silent service' is very protective of its true potential during WW II to this day - more so now I think.

I followed many patrol reports and they had to have this ability to arrive at specific locations in time frames given.

The biggest problem with the sim tweak is if the player sails at 10 kts, they can travel too far - it would be a cheat.

On the draft issue, my understanding is RFB felt the boat sat too high in the water. What is your understanding of their thinking?

[merc4ulfate]

While adequate the slower turning radius was improved after the war with the Top Stern rudder.

Here is some information that I hope helps you out.

http://www.perch-base.org/index_file...ub_Classes.pdf

=========================

This one will open a PDF file that deals with certain aspects of submarine physics centered around torpedo avoidance of the submarine. Some information may be helpful in your search.

http://www.google.com/url?sa=t&rct=j...j1tCPOx9PriImg

============================

Here is a list of manuals and documentation:

http://www.hnsa.org/doc/index.htm#ss

============================

Submarine manual 1942:

http://www.hnsa.org/doc/s-boat/index.htm

[Hitman]

You were/are at kickinbak right?

If the nick still matches, you are talking to no other than Frank Kulick

[aanker]

Originally Posted by Hitman

If the nick still matches, you are talking to no other than Frank Kulick

I am honored - thanks for the TS info : )

I like to use his method of attack with no TDC.

Happy Hunting!

[TorpX]

Originally Posted by cdp44

My ship pack contains ships ranging from small armed fishing boat to New Mexico battleship, so if you need help testing those physics, I can help. No freighters or tankers at the moment, but I can whip something up if needed.

Here is the thread

http://www.subsim.com/radioroom/showthread.php?t=188786

Cdp44

I'm glad you posted that. It will help me a great deal to be able to "drive" some surface ships around, and see how they behave.

I wasn't able to get them to work with RFB, so I will have to either figure out how to adapt them, or use GFO for some tests.

About the freighters; I would like to test a few to make sure they do what they are supposed to. Is it difficult to make ships playable? The only thing I really need, is for them to accelerate to max. speed, and check their turning. I'm thinking I need to try some of widely different sizes/speeds. If they respond ok, the the ones in between should be ok.

Originally Posted by aanker

[/INDENT][/INDENT]You were/are at kickinbak right? Ducimus had a divine revelation - not a revolution - he liked to start those .... lol - just kidding... a divine inspiration and thought about battery life and fuel in a different light. The end result was to give a Propulsion expert special abilities in addition to changing the values in the sims.

Yeah, I remember Duci posting about his stratagem. I think this may be the only way to get decent battery performance. When I'm done with the turning/moving stuff, I'll try to figure out how to get a special ability crewman in every boat. I've never done anything with that part of the game. (I still wished I knew why I can't just put in the right number into the file. )

On the draft issue, my understanding is RFB felt the boat sat too high in the water. What is your understanding of their thinking?

I seem to remember reading somewhere, that the widely varying figures for draft, displacement, and speed were due to modifications made to the boats over the years, but I can't remember where I read that. In any case, I don't think the difference would change much of what I'm working on. I've noticed that sometimes when I surface the boat will come up a foot higher than "normal" and get an extra knot, but if I mod the files to have it 3 feet higher, it doesn't change the speed. Whatever values we put in will be "normal".

Originally Posted by merc4ulfate

While adequate the slower turning radius was improved after the war with the Top Stern rudder.

Here is some information that I hope helps you out.

http://www.perch-base.org/index_file...ub_Classes.pdf

=========================

This one will open a PDF file that deals with certain aspects of submarine physics centered around torpedo avoidance of the submarine. Some information may be helpful in your search.

http://www.google.com/url?sa=t&rct=j...j1tCPOx9PriImg

============================

Here is a list of manuals and documentation:

http://www.hnsa.org/doc/index.htm#ss

============================

Submarine manual 1942:

http://www.hnsa.org/doc/s-boat/index.htm

Ah yes, those help. I like the '42 S-boat manual, good stuff.





Did some more experimentation today. I think I can start seriously nailing some things down soon. I have the S-18 pretty much like I want it. The diving and turning are much better. I think I can probably use the same numbers for the S-42. I should get easier as I progress, since I know more about these arcane details now.

[TorpX]

Cdp44,

I installed and used GFO and your ship pack to test a few examples so I would have an idea how bigger/faster ships will work, and to assure myself that what works for the subs will also work on the ships. I'm pretty happy with the results. I didn't really do anything with the turning yet, but checked the acceleration of the Northampton CA, Fletcher DD, and fishing boat (I wanted a slow one for contrast). Your ships have provided valuable data already.


Some of what I've discovered so far:


The mass/displacement of the ships doesn't really seem to change their behavior; rather it is the maximum speed and h.p./ mass ratio that I have to take into account.

Here is a little taste of what I experimented with:

fishing boat _______ 92 tons, max. speed 9.5 kts.
I gave it a 100 hp engine

stock behavior
starting from 0 kt.
to reach 5 kts. __________ 08"
to reach 9 kts. ___________25"

altered behavior
starting from 0 kt.
to reach 5 kts. __________ 45"
to reach 9 kts. ___________ 1'37"


Fletcher DD ______ 1500 tons, max. speed 38 kts., 60,000 h.p.
It must be one of the zippiest ships; if it moved any faster, it would fly.

stock behavior
starting from 0 kt.
to reach 10 kts. __________ 04"
to reach 20 kts. ___________07"
to reach 30 kts. ___________12"

altered behavior
starting from 0 kt.
to reach 10 kts. __________ 16"
to reach 20 kts. ___________ 35"
to reach 30 kts. ___________ 1'11"

[tops out at 33 kts., increased to 38 kts. at battle stations]

If I dampen the acceleration more than this, it doesn't reach it's "maximum speed", so there is a limit as to what can be accomplished here. Still, it is much better than stock.




I will probably go back to the subs now and finish those before returning to the ships. When I've gotten the work with those done, I will post a tutorial here, so anyone who has custom ships, can easily configure them to work well along these guidelines.

So, what do you all think?

[John Channing]

It sounds fantastic and long overdue.

One of the things that has always frustrated me is that all of the literature I have ever seen on the subject is clear on the fact that a Fleet Submarine could out-turn a Destroyer.

Well, sure as hell not in Silent Hunter 4.

Plus when a group of Hunter-Killers leaves one behind before returning to the convoy he always seems to sit in one place just listening. The temptation is to sneak up to PD and give him one broadsides. However the ability to accellerate from 0 to 30 in 12 seconds makes it impossible.

Carry on, good sir.

[aanker]

Originally Posted by TorpX

So, what do you all think?

I like, and am following closely.

The S-Boats may be a different kettle of fish, this should be interesting...

[HertogJan]

Yup same here

Will be interesting to see if there's a percentage change that could address all ships.

If so? A script could be written for 010 to adjust all units in the sea folder.

That would save you alot of work.

[merc4ulfate]

So a Fletcher goes 0-30 in 1'11" ??? 1 foot 11 inches???

What am I missing about your figures?

Are you trying to say 1:11?? 1 minute 11 seconds?