Help me help him, please

[Still Learning]

So our new game is a pirate game and for reasons irrelevant one of our own needs to reroll. Help me with build ideas please?

He loves the assassin creed main character and has failed at his assassin type many times

We're pirates, ship combat is common as is boarding enemy vessels

Needs to be effective from level 2

20 point buy

Pretty much anything from the srd is a go but paizo pathfinder only

Zero spell casting, he hates it in even simple forms

My thoughts go to ninja, but you are smarter than me.

[VRMH]

I'd suggest Ranger instead of Ninja. Less subterfuge, but packs a bigger punch while still maintaining "sneakability".

[A highly regarded expert]

Did he die? What was he before?

[Still Learning]

Not dead, but going into npc land for some bad decisions. He was a rogue so trying to avoid that directly, and maybe actually get something closer to a stealth assassin/infiltrator.

[Proley]

Maybe go with a monk and a ninja dip later on? Good Saves, acrobatic abilities, High Jump/Slowfall to allow hopping from the crow's nest into a hay pile below to escape your pursuers?

Monk allows you some AC without having to wear armour. facilitating the assassin wandering through the market looking like an average merchant, before drawing his hidden blade and laying hurt down on his target with a flurry of blows eviscerating him?

Assassins Creed melds mobility and combat prowess, so I think monk is a good fit, but ninja could work too, I just think it may be a bit too squishy.

The ninja dip later allows for hidden weapons, disguises, the benefits from sneak attack and such, but taking monk the first few levels would help round out your saves and such, plus an assassin is a weapon in and of themselves, so the unarmed focus does that pretty well. The actual assassin class, from what I've gathered, isn't that great at being an effective assassin, but that's just what I've gathered, someone else can probably speak to that a bit better though.

[Still Learning]

The monk thing is good, I bet he'd like that. If monk can be worked in but still use real weapons instead of always unarmed. Unfortunately there is a distinct lack of hay on the ship so far so we may need a backup method of using stealth.

[Proley]

The hay was a reference to Assassins Creed, but the gist remains the same, slow fall will help him address elevation differences in ship to ship combat nicely :)

He could always hop aboard the ship, take out the lonely watchman, steal his clothes and such, toss him overboard, then "stealth" is being in disguise as tony the watchman, and releasing flurry of blows on baddies as necessary :)

There's nothing preventing a monk from going armed (as treantmonk says, the builds are the same, since an unarmed monk becomes an armed monk as soon as he draws a weapon), he'll just be using a more specific set (there's some solid monk weapons).