My EU-Fu is failing me, and I'm trying to recall whether any Star Wars ships have ever been shown operating underwater (excluding obvious submersibles like the Bongo). Luke's X-Wing didn't seem to suffer on Dagobah, but was only in shallow water for a short time.

I remember an old Marvel Star Wars issue called "War on the Water World" or something similar, where the Falcon had crashed and was floating. But could a starship/fighter operate under water using thrusters/repulsers etc? Would systems designed for use in atmosphere or vacuum be affected by being submerged? (Engines, Guns). How about pressure on the hull?

Just wondered what are your thoughts. What's to stop a starship doubling as a submarine?

"Do you have any idea how ridiculous it is to hide a starship at the bottom of the ocean?" --Scotty

That's an interesting question I'd like to know too, actually. One great thing about Star Wars is the variety of weird and exotic locales, including water-planets like Kamino.

Here's a few I could find. Underwater capabilities seem to be a relatively common design in Mon Calamari engineering, at least for ships of freighter size and smaller.

Also, it's worth noting that Saga Edition's Scum & Villainy had Amphibious seals available as a readily available (albeit pricey) system to install on any starship. So it's present in the EU, if a little unusual. It's like a lightsaber having environmental seals so as to work underwater. Not unheard of, but not completely common.

http://starwars.wikia.com/wiki/Amphibious_Interstellar_Assault_Transport/infantry

http://starwars.wikia.com/wiki/Amphibious_fighter

http://starwars.wikia.com/wiki/DeepWater-class_light_freighter

http://starwars.wikia.com/wiki/Trident-class_assault_ship

http://starwars.wikia.com/wiki/MC-18_light_freighter

http://starwars.wikia.com/wiki/Nautical_Star

EDIT: Also, "What's to stop a starship from operating as a submarine" is water pressure. Lots and lots of water pressure. Gotta reconfigure the shields or do something else engineeringly (that's where the high price of the amphibious seals comes from, I'm sure) to make a starship capable of holding an atmosphere or so of pressure IN while in vacuum also capable of holding OUT under many atmospheres while submerged.

There's one in an old WEG D6 supplement - Stock Ships (WEG40150).

Its called the Mon Calamari DeepWater-class Light Freighter.

I can try to take a scan from my copy & send to you if you need.

Ah the Mon Cals! I looked up their starships but missed some of those others.

Awayputurwpn I am kicking myself. I saw the Clone Wars eps with the Trident in, totally forgot about them! And those amphibious seal mods sound exactly like the kind of thing I was looking for, will have to try and track down that book. Cheers!

Yeah, I did mention the water pressure idea. Makes sense.

Aethis thanks, I think that other list will suit my purposes fine

For what it's worth, I made a handful of submarine-capable starship stat blocks as part of an adventure that ended up on Mon Calamari. You can see it here: http://community.fantasyflightgames.com/index.php?/topic/90148-maps-modules-and-map-creation-materials/#entry862480 (It's the adventure "Echoes of the Past")

Also the old WEG module "Battle for the Golden Sun" had a Spaaaaaaace Booooaaaaat!

http://starwars.wikia.com/wiki/Explorer_%28space_boat%29

So you know.. if you don't want a Mon Cal design...

Actually, this is mentioned in EotE material as well.

"The Deepwater Docks" sidebar, Suns of Fortune p.33:

"An enterprising smuggler must rig his ship to withstand the crushing ocean depths and install underwater propulsion devices on the outer hull."

It doesn't specify, but my guess is the ship uses repulsors to lift from the surface again. There are no stats given for the modification, but a 1-hardpoint attachment costing 1,500-2,000 times the Silhouette sounds about right, with the caveat that underwater Speed is halved, and underwater Handling is -2.

EDIT FOR SHIP SYSTEMS: Sensor effectiveness will obviously be greatly reduced, unless you also include sonar (which could be a mod for the above attachment). Thrusters, blasters, and proton torpedoes could be a BAD idea (do you really want that much superheated water inside your ship's engine and weapon ports?).

Lasers will be inaccurate (probably two Setback dice) due to refraction, and ion weaponry would probably suffer the same, but gain Blast with a radius of short range. Missiles wouldn't work, but you could have another mod for the above attachment to give them an aquatic torpedo function instead, with all the same rules.

And if the liquid is something other than water...results will vary

I would think that the vessel would have to be purpose-built to function as a submarine, or undergo extensive modifications. There are huge engineering differences between keeping pressure in an keeping pressure out.

Not only that, but submerged pressures rapidly escalate way beyond that of an atmosphere. At 50m depth, you are at approximately 6 atmospheres of pressure. That's a heck of a lot of pressure.

I am doing a necro on this thread as there doesn't seem to be a lot of info on underwater adventures. Do any books spell it out, other than:

On 1/30/2014 at 2:48 AM, Joker Two said:

"The Deepwater Docks" sidebar, Suns of Fortune p.33:

"An enterprising smuggler must rig his ship to withstand the crushing ocean depths and install underwater propulsion devices on the outer hull."

Here is something I put together, based in parts from some info Christopher Hunt has here

Starships underwater without appropriate modifications:

• Handling drops -2

• Speed drops -2 (min 1)

• Weapon Range reduced by 1. Add Inaccurate 2

• Max Defense drops -1 . This represents the shields bolstering the ships hull to withstand the pressures of being underwater

I don't want to make it impossible for an unmodified ship to go underwater, as it will be an integral part of my next game, and the player may not have time or resources to find an underwater vessel.

The most excellent @GM Hooly has pointed out to me that there is the Amphibious Modification from Special Modifications. This states:

"Most starships speeders, and other vehicles not specifically designed for it are unfit for usage underwater Starships are typically not hydrodynamic. and hulls designed for zero gravity and atmospheric use can suffer damage from deep-sea pressure. However. with the addition of turbines. modifications to the engines. and reinforcement of the structure. almost any vehicle can be made seaworthy. This attachment can be applied to any vehicle or starship that can enter an atmosphere."

So the question remains, are there any rules stating what happens when you do take an unmodified ship underwater?

Perhaps added to the above all maneuvers are upgraded once? That gives a chance to add damage and strain from the pressure.

I think the main problem is unmodified the ship has way to move as the engines are not made to work and a ship will take damage over time from the pressure

I'm reminded that the SJGames Forums had a similar discussion (probably about a decade ago) and if you want a truly in depth and thorough understanding of the issues in having Submersibles and Spaceships act like each other and have HOURS to spend following that in depth discussion, please check it out! (One of the cool things about the SJ Games forums is that the search function works VERY well and the participants are among the smartest and knowledgeable individuals that you would EVER interact with).

I'll try to be brief and give a synopsis of why you won't see a lot of these ships.

Medium :

Vacuum, Air, and Water don't act like each other. Drives that are designed to work well in Water won't move air. And neither will work in vacuum. And an engine designed to work in a vacuum will blow up the ship if you activate it in water.

Air itself can be prickly too. Take a look at a ram jet. It won't work in lower atmosphere and at low speed! If you want a ram jet you have to either build a hybrid engine that acts like a regular turbo jet at low speeds, then blocks off the air flow to the turbine and reroute the air to a ram jet chamber. OR you can mount multiple types of engines, half ram jets and half "slow" engines. And that's just for AIR.

So a Submersible Starship will need multiple drive systems to motivate through multiple media. We CAN (and have) built trucks and cars that act like boats, but those vehicles travel over road and water not nearly as well as vehicles dedicated to only one mode of transport because . . .

Mass(Weight) :

Submarines are heavy. They are built to be sturdy, because if they aren't, then they get crushed like an empty soda can under the tender mercies of a steam roller.

Spaceships are generally built as lightly as possible because it's VERY HARD to move spaceships and the less mass that you can try to move with space engines, the more likely you are to be successful.

However, the assumption of most Sci-Fi settings (including Star Wars) is that space drives get to a point where you can travel long distances without worrying too much about fuel or drive mass. And then we start loading weapons on ships and armor becomes a thing.

In Star Wars we can move past the question of possibility and assume that vehicles like this are possible. However, they won't work as well as ships dedicated to a single task. (eg: X-Wings make GREAT fighter craft and wreak great havoc and destruction when needed but it's impossible to carry any meaningful cargo in them. A YT-1300 on the other hand isn't necessarily a great combat platform and on it's own is a death trap in a dog fight, but if you need to get a precious cargo somewhere fast, it's just what you're looking for).

So any vessel that can act as both as spaceship and a submersible won't be breaking any speed or performance records in either category.

Balance and Dynamics :

The other thing that will make it harder (if not impossible) to build a submersible space ship is how vehicles are built for balance and how they are designed to move through the media that they are designed.

Submarines are bottom heavy. Modern subs HAVE to be bottom heavy because if they tip over the whole system falls apart and they plunge to the depths of whatever body of water they are in. Yes you CAN engineer a sub to be able to roll and pitch over . . . but that means that you need to add components and weight.

Next, lifting bodies (Air craft) need to be designed to balance their weight at the apex point of their lifting structure. Weirdly enough their drive systems are also angled to push the vehicle down which (conversely and paradoxically) promotes lift.

A Space Ships on the other hand need to be balanced so that their drive systems are perfectly balanced to provide equal thrust along the total mass of the ship from the direction of the vector of intended travel.

So for you to pull off this engineering feat, you're looking at a vehicle with at least three different drive systems and the need to reconfigure the mass configuration of a vehicle for three different design considerations. And that kind of engineered configuration a bit more likely in RoboTech than in Star Wars.

Still not impossible?

Contragrav

It's a magical technology in Star Wars that would make this kind of vessel more likely. If you can modify how gravity affects a vessel, than these issues become easier to solve. But they're still going to add mass and components to the ship in question.

Conclusion

Yeah, I think it's plausible enough in Star Wars to have vehicles like this and it's certainly most likely that the Mon Cal are the group that would be best invested in pioneering this type of vehicle.

BUT

Any vehicle like this will be built for specific purposes to meet rare needs. These ships are likely to be rare and infrequently encountered because they have a isolated specialization.

They're going to be heavier, slower, more massive, maybe better armored, but less armed.

The obvious next logical question would be, who would want this kind of ship and why?

5 hours ago, Mark Caliber said:

I'm reminded that the SJGames Forums had a similar discussion (probably about a decade ago) and if you want a truly in depth and thorough understanding of the issues in having Submersibles and Spaceships act like each other and have HOURS to spend following that in depth discussion, please check it out! (One of the cool things about the SJ Games forums is that the search function works VERY well and the participants are among the smartest and knowledgeable individuals that you would EVER interact with).

I'll try to be brief and give a synopsis of why you won't see a lot of these ships.

Medium :

Vacuum, Air, and Water don't act like each other. Drives that are designed to work well in Water won't move air. And neither will work in vacuum. And an engine designed to work in a vacuum will blow up the ship if you activate it in water.

Air itself can be prickly too. Take a look at a ram jet. It won't work in lower atmosphere and at low speed! If you want a ram jet you have to either build a hybrid engine that acts like a regular turbo jet at low speeds, then blocks off the air flow to the turbine and reroute the air to a ram jet chamber. OR you can mount multiple types of engines, half ram jets and half "slow" engines. And that's just for AIR.

So a Submersible Starship will need multiple drive systems to motivate through multiple media. We CAN (and have) built trucks and cars that act like boats, but those vehicles travel over road and water not nearly as well as vehicles dedicated to only one mode of transport because . . .

Mass(Weight) :

Submarines are heavy. They are built to be sturdy, because if they aren't, then they get crushed like an empty soda can under the tender mercies of a steam roller.

Spaceships are generally built as lightly as possible because it's VERY HARD to move spaceships and the less mass that you can try to move with space engines, the more likely you are to be successful.

However, the assumption of most Sci-Fi settings (including Star Wars) is that space drives get to a point where you can travel long distances without worrying too much about fuel or drive mass. And then we start loading weapons on ships and armor becomes a thing.

In Star Wars we can move past the question of possibility and assume that vehicles like this are possible. However, they won't work as well as ships dedicated to a single task. (eg: X-Wings make GREAT fighter craft and wreak great havoc and destruction when needed but it's impossible to carry any meaningful cargo in them. A YT-1300 on the other hand isn't necessarily a great combat platform and on it's own is a death trap in a dog fight, but if you need to get a precious cargo somewhere fast, it's just what you're looking for).

So any vessel that can act as both as spaceship and a submersible won't be breaking any speed or performance records in either category.

Balance and Dynamics :

The other thing that will make it harder (if not impossible) to build a submersible space ship is how vehicles are built for balance and how they are designed to move through the media that they are designed.

Submarines are bottom heavy. Modern subs HAVE to be bottom heavy because if they tip over the whole system falls apart and they plunge to the depths of whatever body of water they are in. Yes you CAN engineer a sub to be able to roll and pitch over . . . but that means that you need to add components and weight.

Next, lifting bodies (Air craft) need to be designed to balance their weight at the apex point of their lifting structure. Weirdly enough their drive systems are also angled to push the vehicle down which (conversely and paradoxically) promotes lift.

A Space Ships on the other hand need to be balanced so that their drive systems are perfectly balanced to provide equal thrust along the total mass of the ship from the direction of the vector of intended travel.

So for you to pull off this engineering feat, you're looking at a vehicle with at least three different drive systems and the need to reconfigure the mass configuration of a vehicle for three different design considerations. And that kind of engineered configuration a bit more likely in RoboTech than in Star Wars.

Still not impossible?

Contragrav

It's a magical technology in Star Wars that would make this kind of vessel more likely. If you can modify how gravity affects a vessel, than these issues become easier to solve. But they're still going to add mass and components to the ship in question.

Conclusion

Yeah, I think it's plausible enough in Star Wars to have vehicles like this and it's certainly most likely that the Mon Cal are the group that would be best invested in pioneering this type of vehicle.

BUT

Any vehicle like this will be built for specific purposes to meet rare needs. These ships are likely to be rare and infrequently encountered because they have a isolated specialization.

They're going to be heavier, slower, more massive, maybe better armored, but less armed.

The obvious next logical question would be, who would want this kind of ship and why?

A Mon Calamari.

1 hour ago, Tramp Graphics said:

A Mon Calamari.

This, and I also keep in mind that Star Wars is Science Fantasy Fiction and I don't let physics get in the way of a good story.

I will stick with my initial thoughts below:

On 2/24/2020 at 4:05 PM, Andreievitch said:

Starships underwater without appropriate modifications:

• Handling drops -2

• Speed drops -2 (min 1)

• Weapon Range reduced by 1. Add Inaccurate 2

• Max Defense drops -1 . This represents the shields bolstering the ships hull to withstand the pressures of being underwater

On 1/28/2014 at 5:05 PM, MrDodger said:

What's to stop a starship doubling as a submarine?

Physics.

19 hours ago, Mark Caliber said:

Physics.

21 hours ago, Andreievitch said:

I don't let physics get in the way of a good story.

We saw Luke's X-Wing underwater in Episode 9.

28 minutes ago, CloudyLemonade92 said:

We saw Luke's X-Wing underwater in Episode 9.

Also in Episode 5.

we don't see it FLY out of the water nor was the water deep at all

On 2/28/2020 at 2:20 PM, Oldmike1 said:

we don't see it FLY out of the water nor was the water deep at all

Yeah, I've seen a car get submerged from flash flooding, but that doesn't mean it becomes a functional submarine.

The way I usually do it in my games is that ships are limited to speed 1 underwater due to travel being repulsor-only, weapon ranges being limited and weapon efficacy going down in damage due to losing energy from superheating the water. The steam bubbling up from weapon discharges causes two black dice for movement. The person serving as engineer must also think of a way to rig the hull for underwater travel. Ships in Star Wars undergo EXTREME maneuvering, so their structures likely are strong enough to withstand the pressure, but the hull itself would be pushed between the ribs and stringers like cheese through a grater unless they reinforce the hull. Armor helps with this and removes one purple die from the difficulty due to its physical toughness. Sealing the hull to prevent water entry is a must, and you cannot go below a certain depth no matter how well sealed your vessel is.

Also, considering how much Star Wars vessels rust in the vacuum of space, I estimate they'd last thirty minutes under a saltwater ocean before their hulls are totally eaten away.

Personally, I would suggest a vacuum/air capable starship which can float on water (maybe using repulsors or something to keep it from sinking) and enough cargo space to carry a real submersible which it can then launch into the water. To me that sounds both safer and possibly cheaper.

I'm sure the hyperactive is usable underwater too. When accelerating to lightspeed, the difference between atmospheric resistance and water resistance is meaningless. So by combining this with hyperspace-skipping, Mom Cal cruisers can hide by jumping from the bottom of the sea on one world to the bottom of the sea on another without ever exposing themselves.

Oh how I hate Disney's take on hyperspace.

2 hours ago, HappyDaze said:

I'm sure the hyperactive is usable underwater too. When accelerating to lightspeed, the difference between atmospheric resistance and water resistance is meaningless. So by combining this with hyperspace-skipping, Mom Cal cruisers can hide by jumping from the bottom of the sea on one world to the bottom of the sea on another without ever exposing themselves.

sorry to bring back real life physics into this but... just no

water resistance is orders of magnitude higher than air, this is why irl, you can conceivably protect yourself from bullets by being submerged a short depth in water

also, an oldie from legends if you want an underwater capable starship: trident class surveyor ship

https://starwars.fandom.com/wiki/Trident-class_surveyor_ship