To the Bottom of the OCEAN!!! Pic heavy

[Pebbles]

Howdy folks pebbles here, For my first mission report, While in space assembly of my space station is continuing at a respectable pace after it's obliteration, It's a good time to goof around and experiment, I know a fair bit about space but I know very little about the ocean.

And Why not, The oceans of Kerbin are NOT water. *Everything* of Kerbal design is positively buoyant I tested this by throwing stuff into the ocean, Giant tanks filled with various resources Monoprop, Liquid Fuel, Solid Fuel, command pods ect... All float. Because they are all less dense than the "!Water"

Looking at the ResourcesGeneric.CFG of the game you can see the densities of the various elements. Densities are listed as 1X (Liter)=Y (Tons)

So we need something heavier than Solid fuel, which I confirmed floats. Assuming Oxidizer is Liquid O2 We guess it's Atomic weight is 32, So Lets work with Mercury instead... Mercury has an atomic weight of 200,

200/32= 6.25 X 0.005 = 0.03125

Lets Add that.

{

name = Mercury

density = 0.03125

flowMode = ALL_VESSEL

transfer = PUMP

}

Now I simply create a Mod Part a fuel tank that contains this instead of Fuel or whatever... (I choose the toroidal fuel tank with 30L of the stuff) Remember it's a Misnomer to presume a bigger tank is better, Either an element contributes negative buoyancy or it doesn't, If it dose then volume is only necessary to overcome the buoyancy of other elements in the craft. Hence why Fat people float better than skinny people. Despite fat people begin more massive.

Annddd!!! Nope! Still a floater!!!

I mean wowsa... This stuff is Viscous, I guess in the Kerbal universe Blood isn't thicker than water... Nothing is thicker than water not even Osmium. Although this dose explain why kerbin a planet 1/10th the size of earth gains its mass to have 1G Gravity. Also Explains why there are no clouds or hydrological sphere at all, You'd need to heat this stuff upto thousands of degrees to vaporize it and if it moved, through a river it would obliterate any land mass it passed over.

SEE WE'RE LEARNING STUFF!

Anyway, Continuing on, unfortunately there aren't many normal elements denser, Osmium which I mentioned and perhaps some Lanthanide's Depleted Uranium ect... But rather than faff around lets really crank it up.

It's not actually Neutronium, That would break anything I loaded it onto. It has a Density of 1.2Tons per Liter, Which is close to non-Collapsed Stellar Core material. And ignore that to the side for now, That comes later.

firstly I need to Put this on a Rover and drive it into the sea to see if I sink and can drive around the bottom.

CRUNCH!!!! Yeah I know I know... Need moar struts... Driving this thing reminds me of the time I used to be fat. You don't feel it until you move with momentum, like riding your bicycle for the first time in years after getting fat.

EAT SCIENCE OCEAN NOW YOU WILL BE CRUSHED BY MY FAT ASS!!! HAHAHAHA!!! Yeah I am underwater it just doesn't render waters surface from the underside :/

Well I thought that anyway, I tried to drive forward, But as soon as I apply inertia the wheels which are buoyant lift up and the thing flips over... Oh well those kerbals needed a wash anyway they never change there spacesuits.

Normally I would consider adding RCS or rocket motors for propulsion but it weighs over 39tons it wouldn't even nudge it, Besides too much fuel is Positive buoyancy.

NEXT EXPERIMENT!!!

This is what you saw in a previous picture, A probe weighted with 30L of Neutronium Attached to an "S-1 Rocket"

S-1 is my "serious business rocket," Normally I'm a gal who's partial to a good scramjet or a well placed Nerva... But I accept that Liquid Fuel rockets have there place. This is for firing 35ton masses (Corvette Class vessels) into Orbit. We're not taking it to orbit today, Suborbital will do. The Engines are to slow it's decent prior to the Chutes fully opening otherwise the abrupt change in momentum rips the probe apart. There positioned up like that because the Neutronium is positioned towards the top and it will flip, Torque is not really happening with the final stage

(note you can see islands in the background because I had to relaunch it I fired the retros prematurely and it broke apart first time)

WHOOOSSSHH!!!

OH YEAH!!!

YEA... Oh it broke...

It's okay the decoupler just snapped off when the mainsail cut out, the snap was too much for it. Had to decouple it manually.

Drouges Deployed now FIRE RETROS!!! FOR DEAR LIFE!!! FIRE!!

Brace for impact!!!

Systems intact! Decent confirmed 0.3m/s I've placed the instruments on the topside of the probe(under the decoupler), My experiment with the rover showed the Camera hates your guts if you go underwater. Chase Cam is the only camera angle that lets you move at all. Helpfully the Altimeter counts upwards the deeper we go.

Telemetry is as follows.

Depth: 35m

Pres: 1.0029

Grav: 9.81m/s

Temp: 20.1

Depth: 160M

Pres: 1.0326

Grav: 9.82m/s

Temp: 19.76

Depth: 213M

Pres: 1.0435

Grav: 9.82m/s

Temp: 19.76

Depth: 379M

Pres: 1.0788

Grav: 9.82m/s

Temp: 19.76

Depth: 427M

Pres: 1.0892

Grav: 9.82m/s

Temp: 19.76

Depth: 494M

Pres: 1.1039

Grav: 9.83m/s

Temp: 19.92

Depth: 545M

Pres: 1.1152

Grav: 9.83m/s

(Remained 19.92 all the way down)

Depth: 601M

Pres: 1.1278

Grav: 9.83m/s

Depth: 680M

Pres: 1.1457

Grav: 9.83m/s

Depth: 767M

Pres: 1.1659

Grav: 9.84m/s

Depth: 822M

Pres: 1.1788

Grav: 9.84m/s

Depth: 915M

Pres: 1.2008

Grav: 9.84m/s

Depth: 1003M

Pres: 1.2223

Grav: 0.985m/s

(Note terrain stopped begin rendered at -1000M)

Depth 1081M

Pres: 1.2416

Grav: 9.85m/s

(Note Probe struck ocean floor)

Pebbles Signing off!

See you next mission.

Oh go on then one last photo, Jeb was busy upstairs while I was doing this building the space station, He caught this nice pic of kerbin from his Spaceplane.

[Dkmdlb]

Science! This is the best thing I've seen today. Now - how to get Jeb a seat on that probe....?

[Hooligan Labs]

This is actually very relevant to my work on a submarine mod! Please read this: http://forum.kerbalspaceprogram.com/showthread.php/23774-0-21-Hooligan-Labs-Balloon-on-Duna-and-More%21?p=572089&viewfull=1#post572089

Do you think the buoyant force in KSP actually works properly? If so, what would be the "density" for air and salt water? It would be possible to generate either in my plugin, perhaps.

[r00t]

Hahaha, that was great! Good job mate!

[Pebbles]

This is actually very relevant to my work on a submarine mod! Please read this: http://forum.kerbalspaceprogram.com/showthread.php/23774-0-21-Hooligan-Labs-Balloon-on-Duna-and-More%21?p=572089&viewfull=1#post572089

Do you think the buoyant force in KSP actually works properly? If so, what would be the "density" for air and salt water? It would be possible to generate either in my plugin, perhaps.

Hmm Good questions... TO THE SCIENCE MACHINE!!!

Both of these were experiments I planned to investigate at some other time but seeing as you actually asked the question I can bump them up the schedule.

Watch this SSSSPAAACCEEEE!!!

[Pebbles]

Further Studies.

Okay so I tried some additional stuff about how kerbins oceans work, Ultimately my experiments created more questions than they answered...

Dose kerbins atmosphere have density?

The easiest way to answer this is to ask

"Can you have negative mass in KSP?"

And following

"Do things with no mass or negative mass float away in KSP?"

To answer this question I created a New element with a Minus Value for density... Now in my mind this could cause 1 of 2 things.

1: Crash my game and wreck my save

2: Create mass effect technology.

As such I called the new element "eezo" After Element Zero. I then modded the element into a fuel tank and loaded it into my game.

It didn't crash my game and the game dose seem to recognise that the element would subtract mass, at the mass listed there is The negative value of the Eezo minus the positive weight of the tank. registering the tank as having minus 7 tons of mass.

So I put it on a craft as you see, and watched the results.

NOTHING HAPPENED!! Aww... I was hoping to "fall" upwards into space. spinning the pod had no special results... So I took this to it's logical conclusion.

Again nothing happened... The engine didn't generate sufficient TWR to lift off. Those Eezo tanks clearly have POSITIVE mass.

A final experiment. I played around with Mechjeb to see what it had to say. Mechjeb suggested that negative mass craft have negative TWR and negative delta V. So part of me wounders if the game handles negative integers like positive ones... Kinda like with my previous mission the altimeter counted upwards the LOWER I got in the ocean.

One final Experiment.

This craft was perfectly balanced to have Zero mass... If something this big truly did have No mass then RCS ought to be able to lift it, Mechjeb had kittens at first saying it had some insane amount of delta V.

the reason why the value is slightly negative is because the more mono-propellant you use the "lighter" you become making you Negative as you started at 0... Ultimately this thing wasn't able to take off, implying that some part of the engine reads the value as positive but other bits accept the negative value.

-----

I'm going to move away from this topic for now I might revisit what's happening here later.

Next... Prototype submarines.

My hypothesis based on my experiments from my first mission is that KSP has buoyancy roughly similar as we understand it in our world and that everything Kerbal made is positively buoyant. However my super-dense material Neutroniumâ„¢ is infact negatively buoyant.

Using this we can build a prototype submarine consisting of a supply of Neutroniumâ„¢ and some other mundane kerbal element. (Liquid fuel in this case) And two vents one that Vents Neutroniumâ„¢ and one that Vents Liquid fuel. Thus regulating the buoyancy of the craft.

Behold!

Of the engines on top, Both are Turbojet engines, but one uses Neutroniumâ„¢ The other uses Liquid fuel, Of course they also need Intake Air, Which I won't provide because I just want rid of the fuel I don't want thrust.

WHOOOSSSHH

FLOOFFF

PLOP!!!

Like before after hitting the water I fell into a dive but rather than ride it out I switched on the Neutroniumâ„¢ pump and sure enough my dive began to stabilize and I reached equilibrium at 103meters Making myself Neutrally buoyant. with 26.8units of ballast and 150units of Liquid fuel.

I vented abit more Ballast to make myself surface I began to rise, however I stopped rising at 3 meters beneath the surface.

I vented a tiny amount more but I wouldn't easily rise. maybe the top 3 meters has different density?

Now for the final stage of my experiment I would vent my positive ballast (My liquid fuel) and I theory I ought to sink again.

However... It didn't happen. I vented ALL of my liquid fuel and I actually rose HIGHER in the water. Cresting my top "Vent\Engine"

Now this is unusual... all of my previous testing suggested that liquid fuel was a positively buoyant material (rockomax tanks full of liquid fuel only float.)

This suggests to me that my hypothesis might be wrong... Maybe there isn't any force of buoyancy at all? Another possibility for this is that a hither to unexplained force pushes anything in water upwards sharply with a strong force, simulating buoyancy, this force acts over the entire surface area of the object, so very large heavy objects like rockomax tanks, float as a result of there surface area, Whereas my probes are extremely small and heavy(over 35tons), with very little surface area, as such it can overwhelm this mysterious "uplift" force of the ocean...

I need to perform further testing to be sure but this looks likely which might put a dampener on submarines... Aswell as warp drive...

I do enjoy this it's like begin one of the old scientists like newton or Galileo where you have to piece together how the universe works, Often making gross misunderstandings on the way.

Like, In the really early versions of KSP before map view it was argued that kerbin was flat. Then someone demonstrated that you could get into orbit and they worked out an orbital parameter table.

[Cashen]

Depth 1081M

Pres: 1.2416

Grav: 9.85m/s

(Note Probe struck ocean floor)

This tells me that pressure isn't modeled for liquids in KSP, it's just continuing the atmospheric pressure formula down below zero altitude. In reality under a kilometer of water, the pressure is about 90atm.

Also dumping fuel decreases your mass but your craft's volume stays the same, so your density should drop and you should float easier. In theory.

[Hooligan Labs]

Great data!

This suggests to me that my hypothesis might be wrong... Maybe there isn't any force of buoyancy at all?

There is a mysterious force I need to further examine called something like buoyantForce. I believe that it acts on anything in water and scales to how deep it is in water (how submerged it is I think). It is based on a fixed number, buoyancy, and applies that opposite of gravity. Thus, a lighter part would float higher even if it has less buoyant stuff in it. Imagine that liquid fuel, in your case, is being replaced with vacuum.

I need to perform further testing to be sure but this looks likely which might put a dampener on submarines... Aswell as warp drive...

Not at all. I'm rather sure that if there is a significant problem I can just set buoyancy or buoyant force to 0 via the plugin.

Like, In the really early versions of KSP before map view it was argued that kerbin was flat. Then someone demonstrated that you could get into orbit and they worked out an orbital parameter table.

Wow, and I thought I had been playing this game for a long time!

This tells me that pressure isn't modeled for liquids in KSP, it's just continuing the atmospheric pressure formula down below zero altitude. In reality under a kilometer of water, the pressure is about 90atm.

Indeed. There are few submarines in the real world which can even go that deep. Water is scary heavy.

Also dumping fuel decreases your mass but your craft's volume stays the same, so your density should drop and you should float easier. In theory.

Something like this is what I think is happening.

[BigFatStupidHead]

...I vented abit more Ballast to make myself surface I began to rise, however I stopped rising at 3 meters beneath the surface...

...Another possibility for this is that a hither to unexplained force pushes anything in water upwards sharply with a strong force, simulating buoyancy, this force acts over the entire surface area of the object, so very large heavy objects like rockomax tanks, float as a result of there surface area, Whereas my probes are extremely small and heavy(over 35tons), with very little surface area, as such it can overwhelm this mysterious "uplift" force of the ocean...

This surface phenomenon is quite interesting. Earlier submarine experiments found near-surface submarines were much more controllable than those which travelled slightly deeper.

Also, the sub behaves weirdly in regard to depth. Your 'buoyancy' has relatively little effect on the water's surface, and it takes some time to sink fully, especially if you have a lot of bits that, well, float. As long as you're barely underneath the surface, you can actually go around quite well and the sub tends to stay mostly horizontal. Once you get down lower, though, it's sort of like breaking surface tension: suddenly the 'buoyancy' becomes far more responsive, and the sub tends to go vertical one way or another, and usually starts heading down.

I suspect that this upper boundary may also have something to do with the "splashed down" loss of parts.

[Hooligan Labs]

This may help. I had Debug.Log curn out the buoyancy of every part in a ship and its buoyant force.

As you can see, buoyancy is 1 (standard) for every part. The upward force mostly seems to be determined by how submerged the part is. There is another variable called "water level" that I did not print...

It seems that force should be in kilonewtons. That does not seem like a lot (1.5 kN is the output of an ANT engine)... I strapped 3, then 4, then 8 ANT engines on the same vessel and could not make it take off. Spooky.

Edited August 6, 2013 by Hooligan Labs

[Geschosskopf]

Bravo to Pebbles for making something that actually sinks in Kerbin's ocean!

I myself have made some very limited and mostly futile experiments on the water. Perhaps my observations might help, although I suspect you already know this stuff. In my experiments, I was just using stock parts apart from the Firespitter part that makes your vehicle spawn in the water. The actual vehicles were all stock parts, no boat mod parts or airplane floats at all. Anyway....

1. Conventional boats having their hull in the water, when made of stock parts, are a total waste of time. No matter how many rockets you put on them, they hardly move at all. Putting nose cones on the ends of the fuel tank bodies doesn't change this at all. You're lucky to get even 5m/s out of such a boat.

2. Hydrofoils, however, can go quite fast. If you can get the whole main hull out of the water, you can get at least 80m/s (my own record before RUD). You make hydrofoils by putting legs on the bottom of the hull with wings and/or structural panels on the lower ends, these latter parts being angled up about 45^. The more you lift the hull, the faster you go.

3. Despite the relative success of hydrofoils in speed, they are totally uncontrollable. Stock control surfaces, winglets, and canards put in the water have almost zero effect at all, EXCEPT at very LOW speeds. This is contrary to how the hydrofoil fins apparently generate more force the faster they go. I've also noticed this with the rudders on Firespitter airplane floats--you can't turn while taxiing on the water unless you're going very slow, and then turning is painfully slow. Same with hydrofoils.

4. Hydrofoils are dynamically unstable. The higher you get them out of the water, the more top-heavy they become until they roll over and explode spectacularly. This roll cannot be stopped by any number of ailerons either above or below the surface, even though those in the air have enough airspeed to roll an airplane quite easily.

5. When a hydrofoil wrecks, usually you'll have at least 1 fuel tank (part of the hull) stay attached to 1 radially attached I-beam (leg for a set of fins). The amazing thing about this is that when this bit of debris stops bouncing around, it will come to rest with the I-beam sticking straight up in the air, instead of pointing down under the surface as you'd expect. This is especially interesting because it's exactly the opposite of the initial situation with the hydrofoil at rest and intact.

#5 really gives me pause. It suggests that over time, submerged parts lose their mass until it becomes negative. When radially attached, therefore, they move the assembly's CoM away from them, resulting in the visibly heavier side of the tank floating higher than the other.

6. Despite the ability of hydrofoils to rise in the water if their fins are angled up, angling the fins down will not make the boat submerge. There appears to be no change in the level at which the main hull floats and as a result, it never moves fast enough for the fins to do much for it. The only way I've been able to submerge anything was to hold it under with a powerful rocket.

7. There is definitely a strong force below the surface that pushes up on submerged objects. Items forced below the surface will, once the downwards force is removed, rapidly accelerate upwards, MUCH faster than it went down. The upwards force is so great that objects will fly high into the air (like 250m up from 50m down) when they reach the surface. Then of course the objects slam back down on the surface and explode.

All in all, the oceans are strange things. They have a collection of mysterious and often contradictory properties. I've about given up on messing with them.

[Pebbles]

Great data!

Wow, and I thought I had been playing this game for a long time!

That was the friend who introduced me to KSP in the first place I myself am a relative child, I've only been around since 0.19

[Apature rocket science]

I did a it of testing and set the big orange tank to density 10000 and drastically increased the mass, no mater what I did i could not levae the ground even with 67 mainsails.

[Commander Zoom]

Pebbles, I applaud your contributions to SCIENCE.

Well done.

[monophonic]

All in all, the oceans are strange things. They have a collection of mysterious and often contradictory properties. I've about given up on messing with them.

On Kerbin, the oceans mess with you? Reminds me of another place...

“How do you expect to communicate with the ocean, when you can’t even understand one another?â€Â

[rioburrage]

Next you must go the bottom of Eve's ocean!

[cantab]

The easiest way to answer this is to ask

"Can you have negative mass in KSP?"

And following

"Do things with no mass or negative mass float away in KSP?"

To answer this question I created a New element with a Minus Value for density... Now in my mind this could cause 1 of 2 things.

1: Crash my game and wreck my save

2: Create mass effect technology.

As such I called the new element "eezo" After Element Zero. I then modded the element into a fuel tank and loaded it into my game.

http://img.photobucket.com/albums/v63/Darkphantom/screenshot13_zps5d3c2e85.png

It didn't crash my game and the game dose seem to recognise that the element would subtract mass, at the mass listed there is The negative value of the Eezo minus the positive weight of the tank. registering the tank as having minus 7 tons of mass.

So I put it on a craft as you see, and watched the results.

http://img.photobucket.com/albums/v63/Darkphantom/screenshot14_zps4619d497.png

NOTHING HAPPENED!! Aww... I was hoping to "fall" upwards into space. spinning the pod had no special results... So I took this to it's logical conclusion.

http://img.photobucket.com/albums/v63/Darkphantom/screenshot17_zpsd86ef453.png

Again nothing happened... The engine didn't generate sufficient TWR to lift off. Those Eezo tanks clearly have POSITIVE mass.

A final experiment. I played around with Mechjeb to see what it had to say. Mechjeb suggested that negative mass craft have negative TWR and negative delta V. So part of me wounders if the game handles negative integers like positive ones... Kinda like with my previous mission the altimeter counted upwards the LOWER I got in the ocean.

One final Experiment.

http://img.photobucket.com/albums/v63/Darkphantom/screenshot0_zpsa6a7867d.png

This craft was perfectly balanced to have Zero mass... If something this big truly did have No mass then RCS ought to be able to lift it, Mechjeb had kittens at first saying it had some insane amount of delta V.

the reason why the value is slightly negative is because the more mono-propellant you use the "lighter" you become making you Negative as you started at 0... Ultimately this thing wasn't able to take off, implying that some part of the engine reads the value as positive but other bits accept the negative value.

-----

I'm going to move away from this topic for now I might revisit what's happening here later.

I know this is an old thread, but your results are exactly what I would expect of negative mass. It's counter-intuitive stuff. To whit:

A positive force applied to a negative mass will accelerate the mass in the opposite direction of the force. This comes simply from F=ma and keeping your signs correct. So the engine thrusting upwards is actually trying to accelerate the negative-mass ship down, and it doesn't take off.

The gravitational field of a positive mass (Kerbin, say) accelerates both positive and negative masses towards it. For a negative mass, the force felt points away from Kerbin, but as per the above that force accelerates the negative mass towards Kerbin. Therefore a truly negative mass - as opposed to merely a buoyant mass - will not float away by itself.

The experiment I propose you, or anyone who knows how to mod the stuff in, is simple: Make a ship with overall negative mass and an engine thrusting downwards with sufficient force to lift its weight. The weight being calculated as though all the mass was positive. If KSP handles negative mass properly, the ship will take off, flying with the engine burning "the wrong way".