You're now meeting up with the loot van at the docks to secure the meth properly. If you escaped by van you'll start right next to the Loot van, but if you needed to escape by the Chopper, you'll land on the other side of the map.
Start picking up bags and you'll get the objective to turn on the power in the Warehouse to signal your boat. The faster someone gets that light on, the faster the boat gets here, so bolt for it asap.
While you're in the Warehouse, this is actually one of the best places to hold. Start throwing the bags into the back of this black Ute in the Warehouse and hold out for the boat.
After a good while of assaults, the boat will come in at one of the three docks. The boat can only secure 4 bags at a time. Once 4 bags have been loaded in, he'll race off to secure them and start coming back.
The escape Chopper will come shortly after the first boat trip. If you want to secure all the coke you'll have to wait for the boat to come back, but if you're not interested in cash, there's no reason left to stay, so escape.