Loyalty & Duty to your crew?
 

I'm new to GURPS and starting a viking campaign, modeled slightly after 13th Warrior. (The GURPS Vikings book is terrific, btw.) Players will be vikings on a roving ship of about 12 crew (unrealistic, but easier to role play).

What are the advantages and disadvantages required for characters?

On most adventures, most of the crew will remain with the ship and the 2-3 PCs will go ashore with 2-5 NPCs. PCs are 150 points, NPC crew are 75 points on average.

Some thoughts I've had:

[48 point advantage] Allies: 75% power (3 pts), 3 in group (x6), appears almost always (x3)

[20 point disadvantage] Duty to crew

I think the PCs have to take these two and the net 28 point cost, but NPCs on the crew would not pay this price.

The captain is a 200 point NPC. Do I write him up as an additional ally? A patron? (He is slated to die on the 6th of the 8 adventures planned for the overall story arc.)

Re: Loyalty & Duty to your crew?
 

Paying points for allies is paying points for reliability. An ally has nigh unshakeable loyalty and morale or you can supernaturally or technologically control them. Ordinarily, military commanders do not have their followers as allies. Why do the NPCs love these characters so much?

Re: Loyalty & Duty to your crew?
 

Uh. No.

"Your Ally is usually agreeable to your suggestions, but he is not your puppet. He will disagree with you from time to time. An Ally may try to dissuade you from a plan that seems foolish to him – and if he can’t talk you out of the plan, he may refuse to cooperate." (p. 37)

"Blatant, prolonged, or severe betrayal will break the trust between you and your Ally, and he will leave you permanently." (op. cit.)

Perhaps you are thinking of Allies with the Minion enhancement?

Re: Loyalty & Duty to your crew?
 

The important distinction is that an Ally will never willfully betray or abandon you unlike a normal NPC follower.

Re: Loyalty & Duty to your crew?
 

If I created a marine platoon, would everyone be allies with everyone else? I'm starting to think that they wouldn't be allies, and that an ally is more like a sidekick.

This makes me think that maybe the players don't have to take Ally as an advantage, just Sense of Duty to the crew.

Re: Loyalty & Duty to your crew?
 

Nigh-unshakeable doesn't mean "unshakeable" and it isn't disloyal to try to dissuade your leader from doing something suicidal.

Re: Loyalty & Duty to your crew?
 

But their leader does not have "supernatural or technological control" over them.

Re: Loyalty & Duty to your crew?
 

"or" does not mean "and".

Re: Loyalty & Duty to your crew?
 

If he is the only one aboard who knows how to navigate, he certainly has "technological control" over them. But you probably meant, "ability to directly suborn their minds through technological means."

Re: Loyalty & Duty to your crew?
 

As others have said, this is only really necessary if the NPCs are very loyal to the PCs. Ally is essentially spending points to plot-protect the NPCs - it represents a contract between the player and the GM that, as long as the player treats the allies reasonably, they have a guaranteed-good reaction to them, and won't betray or otherwise flake out on the PC.
If you want the players to command the NPCs without enforcing that level of loyalty, consider using Rank instead. If the average NPC has Ship's Crew Rank 0, and the PCs have Ship's Crew Rank 1, then that covers commanding the crew, but without the super-loyalty. You'll want to give reasonable chances to "refill" the NPC pool if some are lost, but the individual NPCs can betray the PCs, decide to leave for random reasons, and take other plot-driving actions.

I would go with a Sense of Duty, rather than a Duty, if you want to enforce the idea that the PCs care for the crew. Alternatively, you could make the crew the PCs Dependents. That would mean that they were guaranteed to be plot elements from time to time (they'd get kidnapped, carried off by sea monsters, get in over their heads in seedy port bars, etc.), and Dependent includes a built-in Sense of Duty towards the Dependents.

I wouldn't bother writing him up as an additional Ally, unless you were planning on replacing him with another, equal-point character after he dies.

Also, bear in mind that it's not necessary to write up all NPCs in GURPS using points. In fact, you only need full writeups, with point values, if they're going to be in a relationship with a PC that is calculated based on point value (Ally, Dependent, Enemy, etc.). If they're not, don't worry about their point value, just give them the traits they need to fill their role. You'll save yourself a lot of time and headache this way, believe me. :-)