Me recently, found some information about the power in the message board of Pirate101 and read all about it! Ratbeard aka the developer, posted this useful information.
1) You cast Gallant Defense on yourself (not on a target). This puts the Gallant Defense "aura" around your character.
2) For the duration of the effect, if an attack is launched at an ally adjacent to you, if you couldhave been the target instead, the attack will target you. You become a magnet for attacks-- melee, ranged, even magic.
It's risky-- but it shouldn't be too risky for a Swashbuckler. Swashbucklers are plenty dodgy. :)
1)Type of Spell: It is an Area of effect that affects all squares directly surrounding your character.
2) Range: It has a range of 1 square in all directions. The effects will only work if your companions/allies are within one square of your character
3) Duration: It lasts a total of five rounds.
4)Effect: Any and all attacks targeted at allies or companions within one square of the caster is redirected towards the caster automatically. The spell ends once your character dies, after 5 rounds, if your companions move out of range(Note: Moving out of range does not cancel the spell it lasts all five rounds so you can have your companions move into and out of range of the effects for 5 rounds, completely at your discretion!)
Fair Sailing, Friends!