Dread Pirate

A pirate is ruthless, efficient, and swagger. This subclass embodies the fierceness of a privateer put into a rogue subclass.

Battle-Ready

A good pirate must always be ready to take the first swing, and that is why they are so good at it. Starting at 3rd level, you add your proficiency bonus to initiative rolls. 

Sunken Treasure

Pirates love rare loot and gold. At 9th level, you can attune to up to 5 magic items at once. You also gain advantage on persuasion checks. You also gain a 50% discount on Large vessels.

Night Crew

You become proficient in two skills, and gain expertise in one. You also don't need to Sleep every night. You no longer take exhaustion until you have not slept for 3 days, and you need to sleep 6 hours for a long rest.

Dread Captain

Starting at 17th level, Every 24 hours, you can call upon your ship. It appears out of the ocean in the nearest port, fully manned with your spectral crew. The ship is 150 x 35 feet, size Colossal, with an AC of 20 in the Hull, and 15 in all other areas. You gain ability to breath underwater forever. You also gain another attack, which can use half of your sneak attack dice. 

 

https://www.dndbeyond.com/monsters/1617170-dread-captains-ship

Dread Ambush

Starting at 3rd level, you become a master duelist. You can trigger sneak attack when there are no allies within 5 feet of you, and there are no more than 2 enemies within 5 feet of you. The normal sneak attack rules apply as well.

When you choose this subclass at 3rd level, you learn how to efficiently damage multiple people through your dread abilities. Your spectral fallen crewmates assault your enemies, Immediately after hitting the your target, select one other creature within 25 feet of the original target. Then roll half the number of Sneak Attack dice for your level (round up), and the both creatures take that much Psychic damage. You can use this feature equal to your proficiency bonus.