Dohlar Blockade

The Dohlar Blockade occured around the Year of God 880. It was King Rahnyld IV's ambition to build a merchant marine from scratch, by levying tolls on vessels within his claimed waters.

Build Up
King Rahnyld IV had decided that the Gulf of Dohlar, Hankey Sound, and Silkiah Bay ought to be closed waters. He'd started out by levying tolls on anyone passing east of the Dohlar Bank and its cluster of islands. Then he'd started pushing his area of operations further west. Eventually, he'd extended his protected area, as far as Whale Island, over a thousand miles from his own coastline. 

Justifications
Claiming to exert a police power over a stretch of saltwater that vast, at that time was quite unheard of. Charis, for example, like virtually every other maritime power on the planet, hewed to the older rule which held that a nation could claim sovereignty only over waters in which it could — and did — exercise an effective control. That didn't mean just extorting money out of passing merchant ships, either. It meant dealing with pirates, preventing acts of war by other naval powers, buoying and marking navigational hazards, updating charts. Generally on Safehold that meant, for all practical purposes, that territorial waters were those which lay within long cannon shot of its coastline, which was agreed to be about three miles. 

Exemptions
And it was worth noting that ships of the Harchong Empire had ended up exempt from King Rahnyld IV's passage fees. 

Raynair's Pride Incident
During the Dohlar Blockade, vessels that were passing through the above mentioned waters, even if there were not headed to a Dohlar port were subject to the passage fee. Some vessels were subjected to seizure and even sinkings in extreme cases such as in the Raynair's Pride Incident.