The ship creaks as Ormidal straightens it's path, but continues to hold together.

Up next is Kallista

Kallista nocks another arrow, holding her position until the serpent appears again.

Sensing Fletcher's fear, the Serpent moves to strike. It moves past him, however, making a B-line for Evi. It spreads its jaws, the sinister blackness of its capacious maw threatening to swallow her whole. Just before it reaches her, Kallista, Tender and Ormidal see Jullar sprint and dive over the rails into the water, taking off his shirt in the process. When underwater, he attempts to gain the creature's attention by flailing about. The Serpent turns it's burning gaze to him. Seeing that he has it's attention, he grabs his instrument, and strums a few notes. Though the noise is muffled, a sudden burst explodes out from the strings, causing a sudden violent rush of water around Jullar.

Serpent CON save: 19

Seprnet CON Save for above: 20

The monster is able to stave off most of the waves effects, but it is still clearly harmed by it. Damage: 11 (Cut in half though, so 6)

Up next is Fletcher

(I mean, No better time to electrocute myself right?)

Fletcher is really quite put out at this point. Nothin like having your terrifying ocean cruse in a broken boat interrupted by an equally terrifying demon, and a much more terrifying serpent. 

Climbing out of the hole he was in (Athletics 2) He sees the snake hurt, and jumps into the water, swimming towards it. As he reaches it, he brings his sword down, still charged with lightning. 

attack 14 damage 7 piercing + 1 lightning + another 2 if he moves next turn.

The blade pierces the Serpent's hide, a black, inky blood spilling out into the ocean. Lightning crackles around the wound, and the Serpent shrieks.

Up next is Evi

With the serpent bearing down on her, Evi quickly shoots an eldritch blast (if it's possible to do so while swimming) at it before futilely attempting to swim away from the creature and back to the boat.

Attack: 14 Damage: 14 (Includes +2 Damage bonus from Genie Patron)

If Evi is attacked this turn she's going to use Hellish Rebuke on it as a reaction for 5 Damage; DC 13 Dex save for half damage.

Evi's Eldritch Blast bounces off of the Serpent's side. It doesn't even notice.

Up next is Tender/Ormidal

Tender hisses through her teeth, tail still lashing behind her as she watches the water, her fists clenched at her sides. She wants to jump in the water, but she knows she can't swim well enough to be of use down there. "Hey!" she yells down to the water uselessly, "ugly water snake!! Quit hiding down below!!" She holds onto a dart, ready to sling it at the serpent if it reappears.

Orimdal focuses his attention on the water ahead of the boat and the surrounds. He searches the horizon for the nearest shoreline and steers towards it (Perception: 6).

Ormidal cannot see a shoreline unfortunately, so he is unsure if he is sailing the right way.

Up next is Kallista

"I'm going to regret this," Kallista mutters to no one in particular, then sprints and dives over the side of the boat. She swims down towards the serpent and attempts to stab it with her sword.

Attack: 7 Damage: 8

Sneak Attack: 5

(Dash bonus action if it's needed to get all the way down there)

(Dash is not necessary)

Kallista, though full of zeal, misses her attack. The water presents different resistances than she is used to fighting in. The Serpent looks towards her, opening its mouth in another kind of malevolent smile. With a swift motion, its tail thrashes out towards Fletcher, and the Serpent darts towards Jullar, closing its jaws around him completely. The monster continues swimming up towards the surface, eventually breaking the top and slithering around the central mast of the ship.

Attack (towards Fletcher): 16 damage: 9

(Gonna take Tender's held attack~)

Upon seeing the serpent, Tender immediately flings her dart at the creature. 

Attack: 8 Damage: 5

(It takes 1 damage from moving)

Fletcher gasps as he is bitten. You see blood stain the water around him. Despite his injuries, He swims towards the serpent. This time he climbs onto the ship....(Athletics 17)

If he makes it he will again attack the creature Attack: 20 Damage: 11 + another  4 if it moves.

(Fletcher was actually smacked by its tail. Jullar was swallowed)

Fletcher is able to nimbly climb up the ship and strike the Serpent, slicing open a large vein. The creature shrieks, tightening its grip on the central mast. You can hear it creak and crack.

Damage to the Sail: 6

(I am an idiot)

(No, it's all good lol)

Up next is Evi

Evi will continue to try and make her way back to the boat (I'm not sure how far away she is at this point).  Whether she makes it or not she'll fire another Eldritch Blast at it to try and make it spit up Jullar.

Athletics if needed: 3

Eldritch Blast Attack: 24 Damage: 9

Hellish Rebuke if attacked this turn: 15, DC 13 Dex save for 1/2 Damage

Evi breaks the surface of the water, not quite reaching the boat yet. Her Eldritch Blast misses the beast as it thrashes around in pain still from Fletcher's last attack.

Up next is Tender/Ormidal