The U.S. Navy is having problems with boarding parties. Traditionally, the Coast Guard handled boarding of ships at sea for inspection. If the navy had to do it, SEALs were usually called in. If necessary, any navy ship could assemble a boarding party on short notice. It was usually headed by a master-at-arms, senior chief petty officer, or a junior officer with some "police" training. But the rest of the party were just a dozen or so sailors that could be spared from other jobs. This works if the boarded ship is what is known as compliant. That means the boarded ship, which is often a rather large one, is helpful. That means letting ladders or stairs down so the sailors can easily get aboard, and being ready to show the boarding party whatever they want. But increasingly, navy ships are running into non-compliant boardings. This means that the ships halts when ordered to, but otherwise offers little, or no, help in getting the boarding crew aboard, or helping them with their search. The boarded ship may have a crew that is angry at being stopped, and not in any mood to cooperate. Or the crew may have something to hide. In these cases, the untrained boarding party is at a big disadvantage. Whenever there is resistance to a boarding, the navy will call in the SEALs, but there may be cases where they cannot afford to wait. So the navy is adding training for boarding parties, something they have not done for over a century. 

The navy is also looking for non-lethal weapons for boarding parties. Now, you either back off from hotheaded crewmen, or shoot them. Moreover, if the boarding party is on a ship carrying dangerous materials (gasoline, explosives, chemicals, or perhaps biological weapons), you dont want to use your guns too much. And if you do use guns, you want more accurate weapons, and sailors who know how to use them. 

A more vexing problem is finding less damaging ways to stop ships that ignore your orders to do so. If the ship in question is carrying dangerous cargo, then firing on it with cannon, missiles or torpedoes might not be a good idea. But better ideas on how to do this are being sought.