“The stickups keep getting bigger, dog. I got knowledge on a boat loaded with brown tar these Vagos eses brought up from Mexico, so much it sitting low in the water. If you can get from them at Chumash, and bring it to my people by the bridge at Lago Zancudo, I'll have some stacks for you. Look out though, they gonna have guards on land and sea.”
Take out the Vagos approaching to defend the boat.
Steal the boat.
Deliver the boat to the drop off.
GTA Online - Mission - Chumash and Grab Hard Difficulty
The mission's name refers to the term "smash and grab" - a slang term for a breaking & entering crime or a burglary. It involves smashing a barrier, usually a display window in a shop or a showcase, grabbing valuables, and then making a quick getaway, without concern for setting off alarms or creating noise.