Topic: Spell question: can Portal really sink a ship?

[Hes]

Hello all,
I always stuck me as sad that some relatively low-level spells can be really detrimental to whole adventure settings. Case in point: "Portal".

I'm running a campaign where two players are able to cast the spell "Portal". This effectively renders sea/naval encounters impossible/moot because the adventurers can simply open a portal below the waterline and sink the ship quite fast. This is way more effective than any elemental attack spell because it works much faster and has virtually no chance of failing (other than a spell fumble, in which case the adventurers try again next round).

Is "Portal" really supposed to be able to do that? Is there any logical explanation that a GM can use to prevent this from happening (i.e. an explanation other than "I don't allow that" 8-) )?

Greetings
Michael

[Defendi]

Where's the spell?  I don't know it by name.

[jdale]

RMU version, on the Closed Essence list Lofty Bridge (it's the same in RMSS, I don't know if RM2/RMC is different):
"6. Portal – Opens a portal 3’x6’x3’ in any solid surface, through which
anyone can pass. At the end of the duration, the surface is returned to
its previous state. Anyone in the area of effect when the spell ends will
be forced back out to the point of entry."

Duration is 1 rnd/level. I'm not sure how many rounds of a 3x6' breach it would take to actually sink a ship, but it's going to cause problems for sure. However the range is touch. I assume you'd have to touch the point where you want the hole. That will require Long Door at least if you are on a different ship, or you could swim over and cast while in the water...

In general, though, magical attacks require magical defenses to counter. Ship to ship combat with a mage on only one side is going to be one-sided. With magic on both sides, it might be different. E.g. I imagine wall spells could be used to significantly reduce the water entering through any hull breach. There must be a usable repair spell as well.

[Defendi]

A few observations.  It says "anyone" and not "anything." I wouldn't personally rule that unattended objects couldn't pass through, but a GM might.

Also, it takes a long time for a ship to sink (depending on size). They are made out of materials that float on their own, after all. However I expect the effects would be bad in a couple of minutes. (The ship would become difficult to steer).

However, this isn't much worse than a bad broadside (that might open the same volume of holes, just divided up in smaller chunks.  Depending on their damage control techniques (If they know how to plug a bad hole with a bit of sail for instance) this could actually be EASIER to fight because there's only one hole to deal with, and the effect is temporary. If this is the kind of thing that can happen in the world, they'd probably have damage control techniques in place already.

And exposing your mage to attack can end badly.

IF the tech level permits, their pumps might come close to keeping up with this.  Not actually keep up, of course, but if they can even do pump one quarter of the water, then you only have to pump four times longer than the spell duration.

I'd personally allow it because it makes for interesting tactics.  If it's too easy of an effect to come by on your world (there are a lot of mages) there would probably be someone on the ship to dispel stuff like this too.

[Hes]

A few observations.  It says "anyone" and not "anything." I wouldn't personally rule that unattended objects couldn't pass through, but a GM might.

That's a nice idea; I previously ruled that you could throw things through a portal or Long Door, but one could argue that substances which aren't "nudged" to go though won't go though by themselves.

Also, it takes a long time for a ship to sink (depending on size). They are made out of materials that float on their own, after all. However I expect the effects would be bad in a couple of minutes. (The ship would become difficult to steer).

I have tried to collect the relevant data from various websites to come up with a guess how fast a ship would sink.

A 3-by-6-feet hole that starts a few inches below the waterline causes about 135 cubic feet of water to enter the ship every second. An empty medieval Kogge-type ship could take about 70-100 tons before sinking. 135 cubic feet of water weigh about five tons. From that I gather that such a ship would sink very rapidly with a portal below the waterline, probably within a minute if not faster.

However, this isn't much worse than a bad broadside (that might open the same volume of holes, just divided up in smaller chunks.  Depending on their damage control techniques (If they know how to plug a bad hole with a bit of sail for instance) this could actually be EASIER to fight because there's only one hole to deal with, and the effect is temporary. If this is the kind of thing that can happen in the world, they'd probably have damage control techniques in place already.

I don't know if there is any feasible way to quickly plug a rectangular hole suddenly appearing below the waterline. That's a little different from smaller holes that don't leak as much water per second. I think only compartmentalizing the ship would help in that regard as a preventive measure.

Greetings
Michael

[markc]

 If the hull had any sort of preservation spell (warding, protection) on it I would give it a saving throw vs the spell working.
MDC

[Grinnen Baeritt]

Like MarkC's post above.... if magic is allowed in a setting then it should be *assumed* that, to some degree, that the ship-builders may have incorperated a certain level of low level warding magic to protect against such spells. There are certainly enough TP spell liists out there that would serve to counter them... Some of the ones in Castels & Ruins come to mind for instance.

With respect tho the exact wording of the spell Portal, I'm not convinced that just allowing "someone" through was the intent of the spell, would that automatically exclude items carried etc? (like the low-level Unseen spell)  ... personally, I believe that the "intent" of the spell is just to open an area briefly (and without damage to the structure) to allow anything that could fit through that space to go through, after all it doesn't say that other stuff can't go through (or come back out the other way for that matter). In this case, I might consider the boat to be an "un-willing target", since the spell is effectively being used as an attack. Thus the boat may get a RR versus the effect.

Also, bearing in mind that the spell is touch... the caster might be sucked though the hull by the force of water due to the pressure difference! Let alone the requirements of casting in/under-water

[Defendi]

There's a trick they used with sailcloth to patch a large hole during the age of sail, but yeah, if these are medieval ships, you're in trouble.  However if they are medieval ships, that mage is incredibly exposed when touches the ship.  He's basically exposed to half the crew when he's doing it.

[yammahoper]

Waterlungs, Underwater Movement and a Hues/Shadow type spell would make the mage nearly undetectable. 

Castle and Ruins has some great spell list used to place protections during construction of a building.  These could easily be used on ships too, which are floating and mobile buildings. 

I also use living ships, grown using Animist magic with ritual and spell mastery.  These ships can repair themselves over time, have plant growth spells used to heal them quickly(even imbed the spell as a daily spell at the helm, in an item owned by the captain/firtst mate/etc), can grow sails or oars and of course resist magic at the level of the "plant".  Spirit of the ship, or even spirits tied to the ship via magic, are also very handy defenses (refer to Essence Companion).

Faillng that: yes a mid level sorceror could destroy a modern day aircraft carrier.  But if such ships always had a platoon of Beast Masters on board with bonded sea creatures following under and around the ship, spell users will have obstacles to deal with.  Even a low level cleric can summon a low level megladon.  I say your best bet if more detail in your cultures, and failing that, a table to roll on that helps you determine the strength of defenses present, including none but a lowly lookout.

[Ynglaur]

A Rune triggered to attack a magician casting Portal could be a nasty surprise.

[Wolfhound]

personally I'd tend to agree with Defendi's suggestion about not allowing "unattended" objects like water to pass through if you don't want this effect to occur.  In fact when characters have cast that spell in the past in games I've run, I usually describe it as the wall/object becomes a shimmering translucent version of itself that the characters can pass through.  I don't think of it as a hole, but as an actual magical portal or limited access doorway.  And as such not allowing other things through sometimes (such as poison gas clouds, or in the case you describe not allowing water through). 

Also on the note of the speed at which the water rushes in (as per Hes's description/explanation), as he stated those rates are within inches of the surface.  While I didn't calculate it myself, the rate that he mentioned sounds reasonable (as someone who works in the chemical industry and works with such concepts on an almost daily basis).   Whereas the deeper under the water line a hole is created, the faster the water will rush in due to increased head pressure (the pressure of the water above and pushing down on the water that is rushing in). 

But as stated by others, if you do allow such a use of magic (personally I probably wouldn't) then such things would be expected to occur from time to time and thus protections would be in place often times to deal with such potentials. 

[providence13]

The party was in the Underdark, in a Drow city by a large cistern. The Mage casts Portal on the water tower as a diversion to slow down some guards. I allowed it but the caster had to make a moving maneuver to avoid the rushing water. The party was slowed down, a bit, by the flood, but they were more prepared than the heavily armored guys coming up the middle of the street.

[PhillipAEllis]

Speaking of magical defenses to Portal, wouldn't any spell or spell effect that dispels magic be able to counter it (if successful)?

[Cory Magel]

While there are variables that could make this easier or harder I think, for me, this would fall in the category of me looking at the players and saying "Do you really want that to be possible?" at which point they'll all realize they don't want their ship to be so easily sunk.

[DangerMan]

While there are variables that could make this easier or harder I think, for me, this would fall in the category of me looking at the players and saying "Do you really want that to be possible?" at which point they'll all realize they don't want their ship to be so easily sunk.

Yup! Thats probably what would happen at my table as well. Well, I would say something like that and the players will in many cases agree, and sometimes not, at which I'll be making "note to self".

This example is in the fine grey area between "creative spell use" and "powerhungry PC looking for loopholes", IMHO. I would discourage the PC using portal to sink a ship, but Im not sure I would dissallow it.

[markc]

I would allow a dispel magic to counter it.

Also then the question arises, if you cast portal to get to a space that is filled with dangerous gas does that gas now expand to fill the space you portal-ed from?
MDC

[providence13]

If the hull had any sort of preservation spell (warding, protection) on it I would give it a saving throw vs the spell working.
MDC

This is what I was thinking, too. I'll bet any boat big enough for someone to think about using Portal will have been Blessed/Prayed over in some Ritual to ensure safe travel.

Sometimes I get the jump on my players. I've thought of another Portal spell abuse. Can it be used as a cannon? The part about "forced back to point of entry" got me thinking.. Portal True could have a long barrel. Combination Heat Solid, Condensation and Portals could be nasty. You get the idea.

Or just an impromptu Jump spell.

[VladD]

I think that if the ship isn't loaded to the brim with metals, that the water would stop flowing in when the level of water inside is the same as outside. Instead of floating, the boat would be suspended in water. The natural buoyancy is enough to keep it afloat for a long time.
Wooden ships normally don't sink because they are full of water, but because the wind is also tugging at the sails and huge waves are pounding them (storm) or during a battle because the wood was already water logged and too many holes were shot in hull so it rips apart at some point. Also fire and human error (such as listing too far over with open gunports) were reasons for sinking. Actually a lot of ships that got damaged were retrieved and fixed and pressed in to service by its conquerer.

Junks (chinese ships) always had compartments and they would stay afloat even if a few of them filled up.

Lastly: I like the "mage is close" If he touches the area from the outside, he gets sucked in by the 50 tonnes of water per second, and smacked down quite hard and the same if he was already on the inside. This is going to a pretty nasty crush attack, which probably repeat a few rounds at the least.

[Hes]

I think that if the ship isn't loaded to the brim with metals, that the water would stop flowing in when the level of water inside is the same as outside. Instead of floating, the boat would be suspended in water. The natural buoyancy is enough to keep it afloat for a long time.

I reckon that would be the case for ships which carry close to no load, or which carry things which would themselves float in water; it probably wouldn't apply to personal transport vessels unless the persons transported abandon ship, though. I any case, the effect would proably be the same: the men aboard the ships are out of action, battle-wise.

Junks (chinese ships) always had compartments and they would stay afloat even if a few of them filled up.

I think this is the best solution if "Portal" is ruled capable to breach ships, partly because it is a valid defense against common non-magical attacks as well. Even if the constructor of the ships didn't expect "Portal" to be used against it, it would be reasonable to build ships this way.

Lastly: I like the "mage is close" If he touches the area from the outside, he gets sucked in by the 50 tonnes of water per second, and smacked down quite hard and the same if he was already on the inside. This is going to a pretty nasty crush attack, which probably repeat a few rounds at the least.

That's a perfectly reasonable nasty consequence as well, which the mage can not avoid by spells like Waterlungs or Underwater Movement. The only way to avoid this would be flying, which means the Portal would have to be at least party above the Waterline.

There are many things to be considered with "Portal" and similar spells; expanding gases where already named, wind/storm or vacuum on one side of the portal would be other questions. At the moment, I'm inclined to rule that substances that aren't themselves actively pushed though the portal won't be transported and that natural forces such as gravity, gas or liquid pressure etc. aren't propagated.

Greetings
Michael

[Old Man]

Sometimes I get the jump on my players. I've thought of another Portal spell abuse. Can it be used as a cannon? The part about "forced back to point of entry" got me thinking.. Portal True could have a long barrel. Combination Heat Solid, Condensation and Portals could be nasty. You get the idea.

Have used Lesser Ethereal Gates as "cannon" by dropping large rocks from other places through the doorway (the doorway being at a high altitude - see Niven's a/o Heinlein's (?) "Rods from the Gods" for example). Btw, read the last Wheel of Time book for all sorts of fun with Portals/Gates.