Sea State & Ship Motion

[iambecomelife]

I have always been concerned about how much the SH3 ships roll and pitch, even when they are in calm seas. I have been trying to find some trigger affecting ship mass that will keep the larger vessels nearly motionless until there is a violent storm/heavy sea state. Does anyone know what to do in order to achieve this? Adjusting the MASS and DISPLACEMENT values in the sim file does not seem to help very much.

Thanks.

[Madox58]

Adjust the gc_center in the sim up or down.
To high and a ship will roll-over.
Set very low and a unit is more stable.
You can also adjust the fr-ratio
.5 is the center of the unit.

[linerkiller]

I have always been concerned about how much the SH3 ships roll and pitch, even when they are in calm seas. I have been trying to find some trigger affecting ship mass that will keep the larger vessels nearly motionless until there is a violent storm/heavy sea state. Does anyone know what to do in order to achieve this? Adjusting the MASS and DISPLACEMENT values in the sim file does not seem to help very much.

Thanks.Good point IABL.
Destroyers are too stable and fast in rough seas, according to seamen's descriptions they should dance like tuna cans...and surely, any speed exceeding 20 knots would surely rip them apart

[Madox58]

There is also drag LR and UD in the sim
The amount of drag left - right, up - down

If you need the reference from the SH3sim.act file?
I can post it.

[iambecomelife]

There is also drag LR and UD in the sim
The amount of drag left - right, up - down

If you need the reference from the SH3sim.act file?
I can post it.

Thanks. I already did some stuff with the drag values but it produced bizarre sailing behavior with the ships pitching violently. I will try manipulating the fr ration to see what happens.

[Subtype Zero]

IABL--

I have also been working on the pitch and roll of various ships, but mainly to prevent the tendency of some ships (tramp steamers, Granville type freighters, LST's, etc.) from sinking in heavy seas. See my brief thread on this topic here: http://www.subsim.com/radioroom/showthread.php?t=138180 I think I have made some significant progress in this area and I hope to update my STzTrampSteamerFix mod sometime later today.

Privateer is correct, of course, about the function of values such as gc_height and fr_ratio. Lower gc_height to get a more stable ship (less roll). I think you can also get more stable behavior by altering the mass and surfaced_displacement values as you indicated you have already tried. Usually, lowering mass results in the ship sitting higher in the water--try the opposite in order to get it to sit lower (you may also have to increase surfaced_displacement to help achieve the effect of a heavier ship). I have also had some success altering pitch with fr_ratio, which seems to be set to a default of .5 for all ships.

I have not tried altering LR or UD drag yet, as I did not know what those values did! Thanks, Privateer, for shedding light on that! :up: I will investigate what effect those values have on the changes I have already made on my ships later today.

[Subtype Zero]

IABL--
How much up or down did you alter the UD drag values? I'm trying to guess a good starting point for changing those values. :know:

[iambecomelife]

IABL--
How much up or down did you alter the UD drag values? I'm trying to guess a good starting point for changing those values. :know:

I changed them to 300 and 500 but this caused some problems with handling. Setting them to .003 (UD) and .005 (LR) and setting weight based on displacement seems to give a good result. The ships sort of plough through the sea instead of bobbing around - however, they still move too much for my tastes. I think the larger merchants should remain almost motionless until there is a very heavy swell.

[Philipp_Thomsen]

The best results I've found was increasing the size of all vessels in the game by 10x.

A ship that has 200m, now has 2000m. But all the ships and subs are 10x bigger, so there's no discrepancy, they all look normal. The good part is the waves, the scenary looks 1000x more realistic. The ships ignores the waves, steady as a rock, like it is in real life. Also, they look bigger, coz if you think about it, the waves are 10x smaller. Now they look like real ships in the water, like in real life. It all looks perfect. We can't reduce the wave size by 10x, coz it would take a computer from NASA to process all that zillion waves (smaller waves, more waves to fill the same space). So enlarging the ships was the only alternative.

Downsides? Some... the ports have to be increased too. As the ship have the same speed, it takes the same time to travell from one place to the other, so no problem there. But in the campaign, it doesn't work, coz in the convoys the ships are too close to eachother, and ships 10x bigger are spawned into one another. The whole campaign would have to be fixed, too much work. But as an experiment, in a mission I've created, it looks fenomenal, just like a movie.

Speaking of movie... I've been watching some movies and paying a lot of attention into the waves. There are a ZILLION little waves in the visual range... really, a ZILLION! There's no way a computer could process that much data, not conciveble to a video card to render that much waves. So what did ubisoft done? Increased the size of the waves, so a computer could process all that sh!t. The results? Ships looks ridiculously small, like plastic ships on a pool. For me, this kills the realism. When you are looking to a ship in the periscope, it seems to have not more than 30 meters. The uboat? Looks like a freaking toy, a 1:18 scale, in plastic.

Someday we will have decent computers to render a realistic world. Until then, this is what we have.

Now you might think... "What if we increase the size of the ships, and the uboats, and the ports, and the trees, and the birds, and everything?"

Well... imagine the workaround to set the entire campaign data, resizing the space between ships in the convoys, all of them. Besides, we would have to study the behavior or the damage. Is it different? I think that the size of the planet can be sustained as it is. I know it would be not equivalent to the ship's sizes, but if we increase it as well, we are back at step one, facing problems with oversized waves.

This is something to think about it. I think that it could turn out to be a incredible idea, and one incredible mod for realism purposes, based on what I've seen for myself here, at my old rig.

Words...?

[iambecomelife]

The best results I've found was increasing the size of all vessels in the game by 10x.

A ship that has 200m, now has 2000m. But all the ships and subs are 10x bigger, so there's no discrepancy, they all look normal. The good part is the waves, the scenary looks 1000x more realistic. The ships ignores the waves, steady as a rock, like it is in real life. Also, they look bigger, coz if you think about it, the waves are 10x smaller. Now they look like real ships in the water, like in real life. It all looks perfect. We can't reduce the wave size by 10x, coz it would take a computer from NASA to process all that zillion waves (smaller waves, more waves to fill the same space). So enlarging the ships was the only alternative.

Downsides? Some... the ports have to be increased too. As the ship have the same speed, it takes the same time to travell from one place to the other, so no problem there. But in the campaign, it doesn't work, coz in the convoys the ships are too close to eachother, and ships 10x bigger are spawned into one another. The whole campaign would have to be fixed, too much work. But as an experiment, in a mission I've created, it looks fenomenal, just like a movie.

Speaking of movie... I've been watching some movies and paying a lot of attention into the waves. There are a ZILLION little waves in the visual range... really, a ZILLION! There's no way a computer could process that much data, not conciveble to a video card to render that much waves. So what did ubisoft done? Increased the size of the waves, so a computer could process all that sh!t. The results? Ships looks ridiculously small, like plastic ships on a pool. For me, this kills the realism. When you are looking to a ship in the periscope, it seems to have not more than 30 meters. The uboat? Looks like a freaking toy, a 1:18 scale, in plastic.

Someday we will have decent computers to render a realistic world. Until then, this is what we have.

Now you might think... "What if we increase the size of the ships, and the uboats, and the ports, and the trees, and the birds, and everything?"

Well... imagine the workaround to set the entire campaign data, resizing the space between ships in the convoys, all of them. Besides, we would have to study the behavior or the damage. Is it different? I think that the size of the planet can be sustained as it is. I know it would be not equivalent to the ship's sizes, but if we increase it as well, we are back at step one, facing problems with oversized waves.

This is something to think about it. I think that it could turn out to be a incredible idea, and one incredible mod for realism purposes, based on what I've seen for myself here, at my old rig.

Words...?

That is a very interesting idea, although it would be a massive undertaking as you said.

One interesting thing I just discovered was that decreasing the drag values seems to have some very impressive side effects on ship handling. Now, after a ship is torpedoed it will careen out of control for a time, sometimes facing at a 90' angle from where it was traveling. It's very dramatic without being unrealistic (this did in fact happen sometimes when a ship lost way). I also noticed that a stationary merchantman will now drift a substantial distance, making it difficult to keep track of ships that you have damaged. IMO this is a very effective way of simulating the effects of ocean currents - many a damaged ship probably escaped because the attacking submarine eventually lost contact and didn't plot its drift correctly.

I would like to incorporate these changes into all of my ships, but first I need to check if there are any negative side effects on the gameplay as a whole.

[Philipp_Thomsen]

A lot of side-effects... :yep:

[iambecomelife]

A lot of side-effects... :yep:

Headache, chest pains, nosebleeds, and dry mouth.

Anyway, one ... side effect I am worried about is the tendency for docked ships to drift. They already move around too much as it is, and sometimes they will ram into the piers until their HP reaches 0 and they explode. Maybe this happens because campaign modders set the speed to 0 without actually checking the "docked ship" box in the mission editor. Then again, it could be an inherent problem that appears regardless of whether the docking option is used. In that case, reducing drag would make things a lot worse.

[Philipp_Thomsen]

I still think that my idea sounds better :lol:

[Wartzay]

@ PT
http://www.youtube.com/watch?v=NE_ri8PkihE
http://www.youtube.com/watch?v=3x3MXiMR0po
http://www.youtube.com/watch?v=VJI_MbLWeHg
http://www.youtube.com/watch?v=SUQLLk86_YQ
:o:o

[Philipp_Thomsen]

exactly... see what I mean? Even in the middle of a storm, the ships don't roll as much as they do in sh3, and the waves are much smaller than in sh3. When the wind is at 15m/s in sh3, the waves are almost half the size of the ship, ridiculous. The ships need to be increased in size at least by 3 times.

[bobchase]

Actually, I have always thought that the ships in SH3 are too stable in both pitch and roll, especially the non-combatants. With 15 m/s (30 knot) winds, the North Atlantic will easily build up 10 ft seas. Even with 3 footers that are widely spaced, a ship will pitch and roll because of the inertia of the ship and the irregular lift of the swells. When a ship lifts on a swell, the inertia of it's weight will often drive it down into the trough of the next swell or, worse, drive it into the next swell so that it can't lift it's bow. Ships do not willingly take seas directly on the bow becuase of this. When you quarter into a regular swell, like most ships do, then you are going to get some rolling action going.

Most videos you see of ships on the Internet grossly overstate the actual wave heights. They also tend to be hand held videos, which is a problem when you are trying to judge pitch and roll because humans tend to stand perpendicular when the deck pitches and rolls under them. When the horizon and the camera are both stable, then the acutal pitch and roll of the ship is hard to judge. Also, the videos taken from super-tankers and massive container ships cannot compare to what a 300 ft destroyer escort or even a 700 ft heavy cruiser will do in the same sea-state. They are just too big.

Take a look at these videos.

This one is of a small US Navy ship about the size of a WW2 Destroyer that highlines off of an oiler. The seas are small (3' - 5') but the oiler's foredeck is going right down to the sea and then pitching up until the bow is almost out of water. Also look at the amidships main deck draining water when the camera moves down the hull. By the way, the wave heights between the ships is caused by the Venturi effect from the ships - they are not indicative of the true sea-state. This is what summer looks like in the North Atlantic. http://www.youtube.com/watch?v=gFoRxSkPHL4&feature=related

This one is from a tanker that is much bigger than anything in SH3. The video was taken in the Indian Ocean but those would be pretty calm seas in the North Atlantic and about average seas in the Pacific. Watch the railing against the horizon at the beginning of the video. http://www.youtube.com/watch?v=Q-yXgS8-IUU&feature=related

This is one is of a huge LPG tanker in a full gale. The seas look about about 8 - 10 ft and they are well defined, just like the SH3 sea always is. It's certainly not a confused sea like the North Atlantic is in the fall and winter months. I believe his degrees of roll that he puts in the super's and he is probably pitching 5 - 10 degrees. Watch the midships crane against the horizon. http://www.youtube.com/watch?v=c2fEv1jr7Vc&feature=related

I've made a few transits on freighters (mostly AO's and AOE's) going out from port to meet my ship. Even in relatively calm seas I'd go airborne in my bunk on the downward falls if I had to bearth way up forward. Once, on an AD (destroyer tender) I was assigned a top bunk. I thought 'how lucky can I get - a top bunk'. Then, as I climed up the other five bunks to get up to mine and looked back down, I thought 'Oh, I get it, these guys are afraid of nose bleeds - Ha-Ha'. Later that night we got into to a bit of rain storm of of Cape Hatteras. The third time my head hit the 12" deck beam that was about three feet above my head I got down and went aft to the mess decks and jsut stayed there. I think that big red crease in my forehead is still there...

Bob Chase

[Sailor Steve]

I'm with bobchase, with a couple of qualifications. I have no problem with the motion of the ships, except that to me the larger ones move too quickly. Big ships get a lot of motion in the sea, but it should be more ponderous. I'm bothered by the number of ships that sink in bad weather, but is that the same thing as just disliking the motion. I also don't like the motion of ships in what should be sheltered harbors, but that's a problem of its own.

Here is an older one of a destroyer replenishing from a carrier. I like it because it's a Gearing, almost identical to the one I was on. I remember doing the same thing, and in about the same weather.
http://www.youtube.com/watch?v=pEqMNAVYR7Y&feature=related

For the most part, I think it works just fine.

[AOTD_MadMax]

In SH4 i have only reworked the UD Drags and the GC-height and all looks fine.

The problem is that you cant choose only one setting for all Units
Each ship needs different settings if you wanne have it realistic !
So it is an hard work to find out the right settings for each ship.

Greets

Maddy

[Jhereg]

Gonna have to agree with Bobchase and Sailor Steve, our current Destroyers are larger and significantly better handling then WWII destroyers. I was most recently on USS Normandy CG 60 and going up forward to the sonar trunk was always fun in even moderate seas. You could skip decks going up if you timed your jump/scramble up the ladder with the downward pitch of the bow into the trough of the swell. Definitely sleep well when underway as the constant rocking even in light seas sure is nice.;)