Trevor has been preparing for a big score in the past few missions and he finally enacts it in this one. He plans to steal whatever valuable thing that Merryweather is hiding.
This mission will include a good amount of shooting and stealth so make sure to make your shots count. Here is everything you need to know about the Merryweather Heist (Freighter Approach) mission and how to get its Gold Medal in GTA 5.
The Merryweather Heist (Freighter Approach) Mission Guide (Gold Medal) – GTA 5

Gold Medal Objectives
Keep in mind the following objectives throughout the level to get a Gold Medal at the end:
- Headshots: Kill 12 enemies with a headshot.
- Accuracy: Finish with an accuracy of at least 80%.
- Ninja: Kill 12 enemies using stealth attacks.
- Container Hunter: Find the container within 1 minute.
- No Alarms: Get to the ship interior without being detected.
Mission Synopsis

The mission begins with everyone meeting up at Floyd’s apartment. Trevor will bring Michael and Franklin up to speed about the heist he has been preparing for.
After the cutscenes, you will be in control of Trevor. Head down and ride a motorcycle with Franklin as your passenger. You will have to head to the bridge marked on your map to bring Franklin to his shooter’s nest.

Upon arriving, you will be switched to controlling Franklin. Get off the motorcycle and go to the vantage point.
Michael will arrive at the side of the Freighter and you will have to snipe the guards so that he can get on board safely.

Scan the Freighter from top to bottom for guards and shoot them from the safety of your position.
Remember that a couple of the Gold Medal objectives require you to land 12 headshots and have an accuracy of 80% so aim carefully. Make sure to take guards out without alerting the others.

The next section will be you controlling Michael on board of the Freighter. With most of the guards down, you can run around the ship and place down four explosives to sink it into the water. Follow the marked points and place down the bombs.
Be careful as there might still be more enemies on the boat you may have missed. Stealthily make your way through the rest of the freighter.

For the fourth bomb, Michael will head inside the boat while you are returned to controlling Franklin. Eventually Michael will plant the last bomb and get out, you will have to assist him by sniping more enemies as he escapes the boat.
Once Michael is cleared from the ship, you can blow up the explosives using your cellphone.
The freighter will sink into the water and spill all of its contents.

You will then be in control of Michael. He’ll be diving into the water to retrieve the object they are stealing for the heist. Head to the center of where all the freight containers are. Make sure to get there within a minute if you want to get the Gold Medal.
You will then switch to Trevor in the submersible once the device has been located. Head to where Michael and the device is. Grab onto the device and head to the safe area at Pier 400 where Floyd will lift you out of the water with a crane.
ALSO READ: GTA 5: Minisub Mission Guide (Gold Medal)

Upon arriving, you will be greeted by Lester. He will reprimand everyone for trying to steal and sell something not even knowing that it was a superweapon.
The mission ends with them having to return what they stole and coming up empty handed.