Hi everyone.  I recently ran an ocean adventure where the party was on a ship with 100 sailors.  They fought off a sea monster but the boat was damaged in the battle and ultimately sank.  20 sailors made a chain with the PCs and some floating jetsam.  After a day, the sharks began to circle.  The PCs used some magic to keep themselves insulated from the sharks.  The sharks picked off several sailors.  A few sailors lost feet but were still alive.  The PCs decide to move their party and makeshift raft as fast from the injured NPCs as possible and did not try to save the injured but took 3 uninjured sailors with them.  Admittedly, it was a very rough situation and besides staving off the bleeding, I don't know what else they could have done.  They were worried if they stayed, the blood and splashing would have attracted more sharks and everyone would have died.

These guys have definitely struggled with alignment before.  To be honest, some should probably play lawful evil or neutral evil.  

There was a lawful good ranger in the party and a chaotic good cleric.  The cleric serves a neutral god who is the god of the Antarctic and prone to pranks and jokes.  

The question is should anyone lose their abilities over this -OR- have to perform some sort of penance?  Or perhaps this is as honorable as anyone could have behaved in a similar situation???

Alignment doesn't define the way a character behaves; it describes the way a character behaves. If you think a character is acting a way different from what's on their sheet, you might tell the player as much. But in game by RAW, there will be few, if any, consequences for the change. In this situation, I don't see where an alignment change would have much impact on the ranger. You know, being LG is not part of a suicide pact. Sometimes you have to save yourself, and staying there wouldn't likely have done much good for anyone else. As far as the cleric, it's going to be completely up to you if the cleric's god will be mad. I'm guessing this is a homebrew pantheon, so it's tough for anyone but you to know how the god would react.

That said, it seems like you, personally, are a bit conflicted about what they might have done better. At that point, it would be tough to punish them. But, if you want to make a rp moment of it, maybe the cleric's god puts him on watch, and communicates this to him, for not doing more to help. Or maybe a god of a place as unforgiving and cold as the Antarctic would understand that sometimes creatures become food. Shark's gotta eat.

Good ideas.  

I think if they had not nearly wiped out two villages of civilians in the previous campaign (just because they wanted their stuff and were willing to commit mass murder to get it) it would not have come to my mind.  We will see what others say but I think you are on the right track.  Thanks for your thoughts.

One situation of acting potentially out of character does not mean there's been an alignment change. People act contrary to themselves all the time. 

If the characters continue to make choices that don't fit with their alignment such that it becomes a pattern, you might consider a conversation with the player about whether that alignment really describes the character they want to play. 

In all honesty, alignment doesn't really have an impact on game mechanics except in extremely rare situations (like with certain magic item attunement requirements or monster abilities like a rakshasa's damage vulnerability). Instead, it's predominately a tool to help players figure out how to roleplay their characters. I'd caution against using alignment as a way of punishing player choices unless everyone at your table is on board with that idea. 

I really only like to think about alignment during character creation, where it's a useful springboard to think about the kind of person your character is. After that, unless you're traveling to different planes associated with certain alignments, I think the less it comes up, the better. 

As far as the cleric goes, they were in an intense survival situation and I think their god can appreciate that. It's not like the wartime doctor performing triage is committing some evil act by deciding who they have the best chance of saving and who they can't, and I think this is a very similar situation. Maybe the character is haunted by the decisions they made, but I don't think it should mechanically effect them. 

It seems they could barely save themselves so no, I don't believe their alignment should change. They might live with survivor's guilt ("it should've mean me, I should've given my space on the raft to them, I could've--,"), but that's the only 'penalty' they should suffer. In addition to that, no loss of abilities should be incurred. The cleric's actions don't seem to go against the tenets or domain of the god (though more information would be welcome), and the cleric still needs to be alive to do good by the survivors. These characters are fine.

I'd only hit people with alignment changes and ability losses if they were consistent in behaviours unbecoming of that alignment/faith, and/or playing a different edition of D&D.

Ok.  I appreciate everyone's input.  Again, I don't think this would have been more than a blip on the radar, barring the previous sessions.  These guys are my friends in real life and I have owned a large business with two of them and never had any problems when we were running it together.  But when they suggested killing tons of NPCs to get better gear, I was surprised and perhaps I have been hard on them ever since in regards to playing their alignments.  We never had arguments when we were in business together and we all did the right thing.  But that is the beauty of the game, you can pretend to be someone else.  

Thanks again

Rather than focusing on the shark attack incident bearing negative consequences, it should be on the fact that they wiped out two villages of civvies.  Were the villages part of a larger kingdom?  What kind of sovereign is responsible for the production output of that land?  Is this a benevolent ruler or a selfish one?  Even a selfish, greedy lord would dislike adventurers who just destroyed the agricultural/industrial output of two whole villages' worth of people.   

I like to play in morally grey setting where the alignment is pretty much meaningless. The shark situation is exactly that, you could find good (and bad/evil) reasons why the characters acted the way they did. Besides the alignments should be descriptive, it should change if players act differently, but without any major game consequences (there should be consequences for the acts themselves though).

I wouldn't suggest forcing players to behave in a particular way because of what they put down as alignment on the character's sheet. 

Having said that - The gods of a given world are likely to be associated with certain alignments, and I think that's perhaps more at the core of the question. Would a god continue to grant powers to someone who does not uphold their philosophy? 

More over - morally questionable acts may also attract the attention of other types of creatures. Devils delight in fresh souls being turned towards darkness, so once the first step is taken, perhaps a few helping nudges will lead them into the situation where their souls can be claimed. So it may not be an immediate impact - but instead, someone actually defending and rationalising their acts on their behalf - encouraging that kind of behaviour until the soul can be claimed (which might also be expedited once the conditions are right)

Simlarly, rumours may spread of their actions - making it hard to gain alliances, and support. 

So rather than arguing about what it said on the alignment box - simply allow it to become a dynamic part of the game. 

More good ideas.  I appreciate it.