Deputies with the San Luis Obispo County Sheriff's Office were conducting routine smuggling boat patrols along Highway One near San Simeon.
Deputies noticed suspicious activity taking place in an area about a mile north of San Simeon Beach. Deputies had spotted a large motor home, two cargo vans and another vehicle in that area.
They followed the vehicles and initiated a traffic stop on the motor home and the car near the junction of Highway 46 and Highway 101.
Several people in the motor home were detained and a significant amount of marijuana bundled in bales was confiscated. Several others in the car were also detained and a quantity of methamphetamine was confiscated.
In the meantime, traffic stops were initiated on the two cargo vans as they were traveling on Highway 46, a few miles east of Highway one.
One van stopped, but the other van led deputies on a short pursuit that ended when the van turned off the highway onto a dirt road and then over a steep embankment, where it crashed.
One of the three people in that van was hurt.
All were taken into custody. The 35-foot drug-smuggling boat was discovered about a mile north of San Simeon Beach.
Four bales of marijuana were discovered still on the boat. Officials said 18 people were taken into custody.
Investigators confiscated 144 bales of marijuana for a total of 3,465 pounds. It is estimated to have a street value of $2.7 million.