Ocean Seeker

Ocean Seeker Rangers are those who are best out on the open water, and feel most comfortable in the water. They form the strongest connection with water creatures and are experts at traversing the open seas. 

Ocean Seeker Magic

Starting at 3rd level, you gain additional spells to choose from. They are as follows: 

1st: Create or Destroy Water, Thunderwave
2nd: Gust of Wind, Locate Animals and Plants
3rd: Water Breathing, Water Walk 
4th: Control Water, Ice Storm
5th: Cloudkill, Cone of Cold 

Bonus Proficiencies

Also starting at 3rd level, you become proficient with Navigators tools, and Vehicles (Water). You also gain proficiency in Survival, and learn Primordial. When making a check about the water, you may add your proficiency bonus onto a Wisdom or Intelligence check, even when not proficient. 

Evasion

Starting at 7th level, your connection with the ocean has made you flexible and nimble at dodging. When you are subjected to an effect that allows you to make a Dexterity saving throw to take only half damage, you instead take no damage if you succeed on the saving throw, and only half damage if you fail.

Tidal Barrage

Starting at 11th level, you can cause a tidal barrage to your target. When you make an attack, you can force your target to make a Dexterity Saving Throw. On a failed save, they take 4d8 additional Cold damage, and they fall prone. On a successful save, they take half as much damage and don't fall prone. 

You may use this feature a number of times equal to your Wisdom Modifer per long rest. 

Whirlpool

Starting at 15th level, you can cause a whirlpool around you. As an action, you can summon a whirlpool with a 15ft radius centred on you, lasting for one minute. Anyone who moves into the space for the first time on their turn, or ends their turn there must make a Dexterity Saving Throw. On a failure, they take 3d8 bludgeoning damage, and are knocked any random direction to the outside of the whirlpool. Any ranged attack against you also has disadvantage. The whirlpool moves with you. 

Once you use this feature, you cannot do so again until you finish a long rest.