The Hague Convention of 1907...

The Avalon Project - Laws of War : Rights and Duties of Neutral Powers in Naval War (Hague XIII); October 18, 1907

Does this treay require a neutral country to refuel a belligerent warship? It seems to me that article 18 prohibits "replenishment" but article 19 seems to allow refueling however another part of the treaty states that if they allow one belligerent to refuel then they must allow the other one to.

 

It allows a neutral port to refuel a foreign warship without it effecting its neutrality, and yes, they must also allow warships from the opposing side to re-fuel if required.

However, the neutral port is forbidden from allowing any foreign warship to replenish its ammo, and from helping aid repairs to the ships war making capabilities, while in its waters.