Is this homebrew Sea Domain Cleric balanced compared to the other subclasses? [closed]

I am making a compendium of homebrew Cleric subclasses, spells and feats, but I want to make sure it is actually balanced and there are no glaring loopholes or broken combos with existing feats, spells, and subclasses before I release it. Is this homebrew Sea Domain balanced compared to the other cleric subclasses?

Sea Domain

The landlubber cultures see the sea as an unconquerable force, so why not harness it to your advantage? The gods of the sea include Umberlee, Posiedon, Habbakuk, and Njord.

Domain Spells

Level
1st Create or Destroy Water, Earth Tremor
3nd Find Steed, Protection from Poison
5th Tidal Wave, Wall of Water
7th Control Water, Watery Sphere
9th Commune with Nature, Steel Wind Strike

Bonus Proficiencies

You gain proficiency in Aquan, martial weapons, and Vehicles(sea).

Sea Master

You become more adapted to life in the water. You gain a swimming speed equal to your walking speed, you can breath underwater, and you know the Shape Water cantrip and can cast it as a bonus action. You add twice your proficiency bonus to any check to navigate at sea.

Channel Divinity: Heart of the Sea

At 2nd level, you can use your Channel Divinity to bolster yourself with the strength of the sea. As an action while you are fully submersed in water, you can spend a use of Channel Divinity to make yourself resistant to all nonmagical damage for one minute. This resistance ends if you begin a turn not fully submersed in water. At 16th level, this ability conveys resistance to magical damage as well.

Channel Divinity: Grace of the Dolphin

At level 6, you can meditate for 10 minutes and use your channel divinity to gain the following benefits until you take a long rest:

  • Your jump distance is tripled while you are swimming.
  • When you are piloting a sea vessel, it moves at twice its normal speed.
  • You can communicate with aquatic beasts, and you have advantage on Charisma checks involving them.
  • You can dash as a bonus action while swimming.

Divine Strike

At 8th level, you gain the ability to infuse your weapon strikes with the divine energy of a crashing wave. Once on each of your turns when you hit a creature with a weapon attack, you can cause the attack to deal an extra 1d8 bludgeoning damage to the target. When you reach 14th level, a creature hit by the attack must also make a strength saving throw or fall prone.

Wrath of Poseidon

At 17th level, as an action, you can summon a whirlpool of watery whips around you. The whirlpool is a sphere centered on you that is 20 feet in radius. It counts as difficult terrain for all creatures except you. Ranged weapon attacks made from outside the cylinder automatically miss any target inside the cylinder. Any creature other than you who starts their turn inside your whirlpool must make a dexterity saving throw, taking 1d10 bludgeoning damage and being pushed 20 feet away on a failed save or take half as much damage and not be pushed on a successful one. You cannot concentrate on spells while your whirlpool is summoned. You can dismiss your whirlwind as a bonus action. Additionally, you learn the Tsunami and Earthquake spells and always have them prepared.