Recently a study done in the Pacific northwest has shown that there are actually three species of Orcas, and they have different diets. The Resident orcas in the PNW never leave here and they eat salmon. But the other Orcas who leave and travel do not.
Two Types Of Orcas Are Actually Two Separate Species, Scientists Argue https://www.iflscience.com/two-types-of-orcas-are-actually-two-separate-species-scientists-argue-73605 One species called the Biggs Orcas feed mainly on marine mammals such as seals, sea lions, and other whales. The other species, the Offshore Orcas, feed mainly on Fish, but they pick on larger fish such as sharks, rays, skates, but not salmon. Some have even been known to attack Great White Sharks. How to stop them from attacking boats, I don't have a clue, but recently a group studying communications between whales have actually been able to talk to whales using recordings of whales sounds. However they don't know exactly what was said, but they're working on that. Maybe they'll figure out a way to simply say "stop". I think the attacks are simply over food. They see boats as competition for their food so they attack it to drive it off.