SDBs can go underwater?

[Blue Ghost]

flykiller, but what happens when that same vessel leaps into orbit and beyond? I'm thinking that a ship could solve a lot of those problem by going into orbit, then burn off all that crud during reentry.

But I guess that depends on the design parameters.

 

[aramis]

There was also a third-party "The Undersea Environment" by the brothers Keith. Awesome. Really wish I hadn't sold it off...

 

[flykiller]

But I guess that depends on the design parameters.

and a ref ruling. "ok, you now have a bunch of carbonized material in the turrets and turret rings. the effect is ...." rolls dice.

too, this assumes that the SDB can break cover safely to do such a burn-off.

 

[Black Globe Generator]

Originally posted by Hyphen:
BG's rule that a hull with "no armor" (Striker AF 40) can withstand 1 ATM; hull with armor factor 1 can withstand 2 ATM, etc etc, is not a bad start.

I wasn't necessarily thinking of a one-to-one relationship between armor and pressure resistance, even if it would be really convenient to be able to do it that way, because...

Originally posted by Hyphen:
Remember however, that standard TL 13 basic battledress (presumably with more moving parts and thus less able to be sealed) can withstand 600 ATM...!!!

...needs to be considered as well.

Do any of the sources for the Dragon-class SDB describe its operational limits in either a gas giant or underwater? It might be possible to identify a scale based on the SDB's armor factor if we have some idea of the specific capabilities.

On the other hand, if the relationship is one-to-one, how well does the idea that a ship with armor-9 can survive to 10 atm sound? Underwater that's roughly 90m or 300 ft - about the operational depth of a Type IX/C U-boat - which seems a bit shallow to me.

 

[Sifu Blackirish]

Off the top of my head, if the craft is not fully streamlined, it can do no more than 'hide' underwater, with movements rates at 1/10th normal.

One requires a 'submersible' design specifically adapted to the sea environment to maneuver or fire qweapons without SEVERE penalties.

 

[Blue Ghost]

I have the Steve Jackson Games deck plans, but they're burried somewhere. Aren't Dragon Class SDBs defined in Traders and Gunboats? Even so I don't recall there being any "underwater" capabilities defined. That's not to say that they aren't there, it's just been a long time since I looked at those pages.

The battledress thing; typically (though not always) the more compact a structure the more resiliant it is to shock; i.e. you can drop both a flea and an elephant from a plane at 10,000 feet, and where both will reach terminal velocity the flea will walk (jump?) away, whlie the elephant will go "splat"

 

[travlar]

Originally posted by flykiller:
being able to submerge is one thing. dealing with long-term immersion in salt water is another. any ship not designed to deal with electrolytic and bimetallic corrosion will soon deteriorate in such an environment - in some cases, very soon.

and, any ship not designed to forcibly repel marine life will soon find itself covered with any number of marine plants and animals looking for a home. hard to fight when there's barnacles growing on the optics and abalone clogging up the missile racks and electric eels trading love buzzes with the EM sensors.

It would seem to me that SDBs would have those capabilities, because they are intended to sometimes stay underwater for quite a while.

 

[flykiller]

It would seem to me that SDBs would have those capabilities, because they are intended to sometimes stay underwater for quite a while.

well one can just up and say "thus", but the game of traveller lets reality intrude once in a while. seems to me that an SDB intended to operate in a marine environment would be purpose-built, would in fact be a submarine.

 

[Lochlaber]

1. There is no way that a vehicle created for vacumn and/or dipping in a gas giant is going to be less than fully waterproof. Air is a lot more slippery, as far as escaping than water is, so if air can't escape, water can get in. If a ship is sealed against oxygen or other gasses from getting out, s much larger molecula should be more of a problem.

2. Marine life does not immediately find something sitting in water and immediately begin to settle and grow on it it takes time and generally
requires still water. Items in the ocean in a current, stay free of growth a lot longer than something in a stilled zone. Given that turrets are probably just as sealed as the rest of the ship, water and organisms aren't likely to get in and grow, especially in the laser tubes.

3. Any spaceship, regardless of it's armoring should be able to withstand 1 atmosphere or more. If a ship can keep it's own atmosphere inside when surrounded by vacumn, it should be able to do so when surrounding by pressure. In fact, the physics should be able to handle several atmospheres without a problem. So if you let a ship dip into a gas giant, it should be able to withstand the same pressures underwater.

 

[Whipsnade]

Originally posted by Lochlaber:
1. There is no way that a vehicle created for vacumn and/or dipping in a gas giant is going to be less than fully waterproof.

Lochlaber,

That's NOT what this thread is discussing. Please re-read the posts.

Everyone agrees that an OTU spacecraft is essentially water-proof. What we're mulling over now are two closely linked things:

A - How long can a standard (i.e. PC owned) craft hide underwater and how well can it operate? And:

2 - What sort of modifications are required for long term submerged and/or gas giant operations like the kind canonical SDBs purportedly undertake.

No one is questioning that the players should be able to gingerly submerge their free trader to a certain depth to avoid a customs patrol sensor sweep. OTOH, we're also generally in agreement that the players shouldn't also be able to sign a mercenary contract and then blithely hie off to hunt TL8 Seawolf SSNs under the seas of Arglebargle-IX in their scout/courier.

It's the second case being hashed out here. Just what modifications should be or need to be done to OTU spacecraft to make them undersea and/or gas giant 'worthy'.

2. Marine life does not immediately find something sitting in water and immediately begin to settle and grow on it it takes time and generally requires still water. Items in the ocean in a current, stay free of growth a lot longer than something in a stilled zone.

Thanks, I'll be sure to let all the off-shore fishermen in my family know that all that marine growth they routinely fight is a figment of their imagination. They'll be greatly relieved.

3. Any spaceship, regardless of it's armoring should be able to withstand 1 atmosphere or more. If a ship can keep it's own atmosphere inside when surrounded by vacumn, it should be able to do so when surrounding by pressure.

Keeping something IN and keeping something OUT are two very different things. A 747 easily keeps a pressure of 1 atm within it while surrounded by very low pressures, yet I won't be using a 747 fuselage to visit even shallow shipswrecks anytime soon.

Anyway, we all agree that OTU spacecraft are essentially water-proof. It's duration and operability that we're tossing around now.


Have fun,
Bill

 

[Liam Devlin]

Hyphen wrote:
From memory (my notes are at home) there was also a Challenge article about underwater combat using MT rules. The article opened with a description of SDB's/submersibles defending a world against an invasion by Lucan's forces.

So there is some stuff out there.

These articles genst are by Terence McInnes, Challenge 53, 54, & 60, titled "Wet Navy Designs 1-3" accordingly. They include Navies of TL-1 to TL-15.

Extremely useful data there..

Likewise, the MT Ref's book also subscribe to the TL-12 (the technology tree page) as the triphibian vehicle era, where air-sea-and space vehicles become "indistinguishable".

Leads me to think SDB's at TL-12+ would have that capability of submersion.

Mayhap before this TL, they do not, or are not space-flight capable?

Ciao!

 

[Blue Ghost]

Originally posted by Lochlaber:
1. There is no way that a vehicle created for vacumn and/or dipping in a gas giant is going to be less than fully waterproof. Air is a lot more slippery, as far as escaping than water is, so if air can't escape, water can get in. If a ship is sealed against oxygen or other gasses from getting out, s much larger molecula should be more of a problem.

2. Marine life does not immediately find something sitting in water and immediately begin to settle and grow on it it takes time and generally
requires still water. Items in the ocean in a current, stay free of growth a lot longer than something in a stilled zone. Given that turrets are probably just as sealed as the rest of the ship, water and organisms aren't likely to get in and grow, especially in the laser tubes.

3. Any spaceship, regardless of it's armoring should be able to withstand 1 atmosphere or more. If a ship can keep it's own atmosphere inside when surrounded by vacumn, it should be able to do so when surrounding by pressure. In fact, the physics should be able to handle several atmospheres without a problem. So if you let a ship dip into a gas giant, it should be able to withstand the same pressures underwater.

1) Untrue. contemporary sea going vessels have smooth undersides to traverse ocean waves, while the topsides are free form structures to accomodate human activity. I'll reference Bill Cameron's 747 analogy as a partial example, but not for the reasons he meant and implied; i.e. being airtight does not garauntee functionality in extreme conditions; it merely gaurantees that air will not escape under normal operattions in the intended environment. Subsequently a Traveller spacecraft/starship, one designed to skim jovian atmospheres and oceans, is possibly, but not garaunteed to be submersible.

2) Is that true for all forms of plankton and related sea flora? I honestly don't know.

3) Ah, but ships dip in oceans, not gas giants. They skim both oceans and gas giants, but I think only dip in oceans. I suppose one could argue that the atmospheric conditions on a gas giant, because of the high pressure (depth/altitude depending) might be "ocean like", but compressed air (regardless of its makeup) is still air. In other words an amonia atmosphere, though extremely dense by normal standards, is still not a liquid, and hence not an ocean. There's still significant space between the molecules; i.e. they're not clinging to one another, nor riding on top of eachother as per an aqeous solution.

If nothing else the characters can garauntee themselves a clean ship by refuelling in a gas giant

 

[flykiller]

If nothing else the characters can garauntee themselves a clean ship by refuelling in a gas giant

unless some kind of floaty-thing lives in there ....

 

[Lochlaber]

Untrue. contemporary sea going vessels have smooth undersides to traverse ocean waves, while the topsides are free form structures to accomodate human activity. I'll reference Bill Cameron's 747 analogy as a partial example, but not for the reasons he meant and implied; i.e. being airtight does not garauntee functionality in extreme conditions; it merely gaurantees that air will not escape under normal operattions in the intended environment. Subsequently a Traveller spacecraft/starship, one designed to skim jovian atmospheres and oceans, is possibly, but not garaunteed to be submersible.

Ok, I'm confused. How does current design of ocean liners, which do not have to maintain a complete envelope around their structue to maintain life support have to do with a ship which does require the complete envelope to maintain life support. Traveller ships should be more compared to submarines than cruise or merchant ships.

2) Is that true for all forms of plankton and related sea flora? I honestly don't know.

Pretty much as far as the clinging stuff goes, plankton grows pretty much as it wants to but it is generally free floating. Plants such as sea weed, barnacles, etc., do better when they start growing in still waters than in a current.

Modern hulls do not provide the many protuberances and declivities that old fashioned wood hulls did. Without someplace to get started, barnacles, etc., take a lot longer to grow and generally are smaller, one reason that wooden navies like copper bottoms.

Metal is in fact very hard for sea life to attach too but once it does, it can spread fast. I've seen time lapse photography of ships sunk to become reefs and you can easily see how sea life takes hold in spots, then spreads from there and that space is often protected from the current and fairly flat. It didn't just flower everywhere at once.


3) Ah, but ships dip in oceans, not gas giants. They skim both oceans and gas giants, but I think only dip in oceans. I suppose one could argue that the atmospheric conditions on a gas giant, because of the high pressure (depth/altitude depending) might be "ocean like", but compressed air (regardless of its makeup) is still air. In other words an amonia atmosphere, though extremely dense by normal standards, is still not a liquid, and hence not an ocean. There's still significant space between the molecules; i.e. they're not clinging to one another, nor riding on top of eachother as per an aqeous solution.

3. Pressure rules are the same, regardless of what is providing the pressure. If your ship can take the pressures of dipping in a gas giant, it can easily withstand the same pressured underwater.

By the way, if your ship can chemically handle a methane atmosphere, which is highly reactive when compared to sea water without a problem, then it can handle sea water.

 

[Blue Ghost]

Point One was more an attempt to address the difference between skimming and dipping, and those activities related to submersion of a hull. My predelection is that just as jet engine nacelles hang from wings on jetliners to scoop air without interrupting the air flow over the wing (the vaccum of which is providing the lift), so it would be with vents placed on a starship for the purposes of skimming. That is to say that refuelling intakes would probably be placed where they'd function best without interefering with other ship functions; i.e. the antenni probably aren't placed on the scoops outer skin, but probably along the ships topside spine. Modern aircraft have antenna portruding both above and below the fuselage. The exception are amphibious designs; i.e. say a PBY-Catalina or similar plane.

So, what does all this mean? IYTU assumes all ships have the same design parameters (like the TL12 example where ships traven through or over land/sea/air/vacuum), then I guess it's a moot point. But I would think it unlikely. As a rich noble who owns my own yacht outright I might, if I were so inclined, to have a submersible yacht. But, as a starship dealer, I might be inclined to have to separate models of yacht for sale to that noble; one that can go under water, and a bargain version that doesn't, but still gets the customer from System A to System B.

You might think of it this way, the Apollo capsules weres designed to splash down in the Earth's ocean. Everything was airtight; from the Saturn 5 boosters to the LEM. But neither booster, LEM, nor even the rover the astronauts used to cruise the moon's surface, were capable of undersea travel.

IIRC Methane doesn't react with alloy steel like sodium.

 

[RandyT0001]

LBB5 p.27
"On streamlined ships, such an installation also includes hoses......for drawing water from oceans."
IMTU ships hover with contra-gravity and drop a hose into the water for refueling purposes since this helps avoid turbulent seas and/or aquatic life that may damage the ship.

 

[Hyphen]

Originally posted by Black Globe Generator:
Do any of the sources for the Dragon-class SDB describe its operational limits in either a gas giant or underwater?

From memory (again! , there was something in Secret of the Ancients, since that adventure had the PC's operating in a gas giant.

[EDIT: Here we go:
"A 3G maneuver drive is required before a vessel can enter the atmosphere below 37,000 km.
Commercial vessels (traders, merchants, liners) can withstand up to 1,000 deg. K and up to 1,000 atmospheres.
Military vessels can handle temperatures up to 1,500 deg. K and pressures up to 2,000 atmospheres. System defence boats are specifically constructed to handle temperatures up to 2,500 deg. K and pressures to 3,000 atmospheres."]

There may also be something in the AHL boxed set, since one of the scenarios was to retrieve a Rampart starfighter from the AHL that crash-landed in a GG. It's actually floating on the liquid surface, so hopefully there's some accompanying rules...

[EDIT: No such luck - it just talks about the scenario itself, and that is pretty basic, not even mentioning stuff like special high-pressure vacc suits (which, IMHO, would be required as per SotA). On a brighter note however, I've just read Traders and Gunboats, and it says that SDB's are often stationed deep in a world's oceans (if they exist), and the implication seems to be this is for long periods of time.]

There may even be some data in MT Journal #3 (the publication that replaced Travellers' Digest) - didn't that have someone being attacked by a GG-critter on the cover??

[EDIT: Bah humbug! This is similar to the AHL scenario, having tasks for the PC's to perform but light on the tech involved. Sorry!]

 

[Hyphen]

Dear Folks -

From "Wet Navy: Part 1":

Hull resistance = sqr root(UCP disp. x resistance factor)
A submerged submersible has an rf of 0.9; a submerged submarine has an rf of 0.3.

I don't think a submarine would be considered an "airframe" under MT rules, so could I suggest that a submarine's hull should be considered "streamlined", while you could consider a submersible to be, in effect, "unstreamlined".

Therefore, an SDB's hull resistance would be sqr. root(400 x 0.3) = root(120) = 10.95.

Power in MW = (resistance x (top speed)^2)/2000
Therefore:
sqr root((Power x 2000)/res) = top speed
sqr root((5000 x 2000)/10.95) = 955 kph submerged, using only 5000 MW of it's 8730 MW power plant...

(Even if I change my mind and use the 0.9 rate, it can still travel at 726 kph...)

OK, so now you know another reason why SDB's are nasty!

Now for max depth ("Wet Navy: Part 2"):
Multiply armor factor by 15, therefore 67 x 15 = 1005 metres is max dive depth.

(This is according to MT; Striker's old system had a SDB's armor pegged at AF 85, so if you're a CT player your SDB's can dive to 1275 metres!

And finally, FWIW, "Seastrike"'s "water as armor" table is as follows:

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

"For purposes of Striker, water has an armor value of 2 per meter.
For High Guard use the following values:
</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">Armor 0 1 2 3 4 5 6 7
Water(m) 30 32 33 34 36 37 38 39</pre>[/QUOTE]Water armor factors are cumulative with other armor, so a High Guard hull factor 0 vessel under two meters of water would have an effective hull factor of 1; a Striker vehicle with armor 10 at the same depth would be equivalent to armor 14."
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

[EDIT: this appears to be using Striker's pre-errata numbers; i.e. 30 m x Striker AF 2 = Striker AF 60 = HG AF 0. Since the errata says HG AF 0 really equals ST AF 40, the initial depths should probably be changed to:
20 metres of water = HG AF 0;
32 metres of water = HG AF 1.]

(Does any of this help?)

 

[travlar]

Originally posted by Blue Ghost:
So, what does all this mean? IYTU assumes all ships have the same design parameters (like the TL12 example where ships traven through or over land/sea/air/vacuum), then I guess it's a moot point. But I would think it unlikely. As a rich noble who owns my own yacht outright I might, if I were so inclined, to have a submersible yacht. But, as a starship dealer, I might be inclined to have to separate models of yacht for sale to that noble; one that can go under water, and a bargain version that doesn't, but still gets the customer from System A to System B.

You might think of it this way, the Apollo capsules weres designed to splash down in the Earth's ocean. Everything was airtight; from the Saturn 5 boosters to the LEM. But neither booster, LEM, nor even the rover the astronauts used to cruise the moon's surface, were capable of undersea travel.

It seems to me that it depends on the price of making ships submersible. If it is low enough (or possibly non-existent), then "submersibleising" would be common for streamlined ships, even if just as a precaution.