Baril, seeing the stairs through the hole, enters the cabin to descend them, using up all his movement within melee range of one of the spiders. He shoves the spider to try and knock it prone.

Spider Athletics: 8

The spider stays standing however, and is able to jump back to dodge the following attack.

Baril(20)Zahira(17)Ilsur(14)Spiders(13)Blue(8)

Zahira, you're up!

Zahira follows Baril down and strikes the same spider.  She then gives it a shove with her mind pushing it 5 ft. Away (DC 12 Str).

Attack: 24 Damage: 10 Sneak Attack: 4

Zahira, thanks to her sneak attack damage, is able to slay one of the two spiders. Its legs curl up as it lies on its back.

Baril(20)Zahira(17)Ilsur(14)Spiders(13)Blue(8)

Ilsur, it's your turn!

Ilsur follows Baril descending the stairs and as soon as he sees the other spider he fires one arrow at it, trying to end the fight as fast as possible.

Attack: 11 Damage: 9

Ilsur's arrow misses its target!

Baril(20)Zahira(17)Ilsur(14)Spiders(13)Blue(8)

The one remaining spider bites at Blue, who is still prone! Attack: 14 Damage: 6 and if it hits, please make a DC 11 CON save to take half of 7 poison damage, or the full amount on a failed save.

It is then Blue's turn!

Baril(20)Zahira(17)Ilsur(14)Spiders(13)Blue(8)

Blue

As the spider lunges at Blue, he holds up his palm facing the creature..."Turma" he utters, and the spider seems to halt in space, it's mandibles clamping down on an invisible barrier.

Blue bounces to his feet, with his palm facing he creature, and suddenly electrical discharges begin to fly between his fingers, and he attempts to slap the spider away.....

Shocking Grasp attack  Attack: 12 Damage: 4

Spent lvl 1 spell slot for Shield to save his ass....Assuming the shocking grasp hit the spider can't take reactions and Blue will back out of range of it....however if it missed he will stay in place not to risk opportunity attack.

Blue's shocking grasp unfortunately misses! He stays in melee range with the spider.

Baril(20)Zahira(17)Ilsur(14)Spiders(13)Blue(8)

Baril, you're up, with Zahira on deck.

(Sorry I was applying pathfinder rules in my last post.  /boink.  How do you want to handle shield shove?  If I'm successful I can get advantage on my attack against a prone target, but I don't know that until you make an opposed check.  In this post I've rolled with advantage, recognizing that if it doesn't apply you can use the first roll.  Let me know if you prefer anything different.)

Baril growls in frustration as the spiders dance about.  He advances on the next, trying to pin it down with his shield before slicing it.

Bonus action to shove: 16

Attack: 24 Damage: 6

Quote from Ashen_Age >>

(Sorry I was applying pathfinder rules in my last post.  /boink.  How do you want to handle shield shove?  If I'm successful I can get advantage on my attack against a prone target, but I don't know that until you make an opposed check.  In this post I've rolled with advantage, recognizing that if it doesn't apply you can use the first roll.  Let me know if you prefer anything different.)

 (I think that's a good way to handle it.)

Spider Acrobatics: 9

(What are the odds? We'll say you win.)

The spider is knocked prone and is cut open by Baril! It is gravely injured, but still kicking at the moment. (SpiB10)

Baril(20)Zahira(17)Ilsur(14)Spiders(13)Blue(8)

Zahira is up next!

Zahira stabs at the remaining spider, going for the exposed underbelly.

Attack: 10 Damage: 13

If it is still alive, she uses her mind powers to push it away,  it must succeed on a STR save (DC 12) or be moved 5 ft. away from me (and blue!)

Spider's STR save: 8

The spider manages to dodge Zahira's attack, but it is shoved away, provoking an opportunity attack from her, as well as Blue and Baril! Go ahead and roll those attacks.

Baril stabs with his sword!

Attack: 14 Damage: 10

(OOC: I’m not gonna be able to post and roll dice till tomorrow feel free to roll my attack. +5/1d8+3)

( Tomorrow will be a long and busy day so, just in case Ilsur will fire at the spider again. If it's dead he will try to hear and see upstairs if anyone had heard the commotion. 

( Attack: 15 Damage: 4

and/or 

Perception: 8 )

Zahira's attack: Attack: 21 Damage: 9

Zahira, after pushing the spider away, manages to deliver the fatal blow! The ship is quiet once more. Ilsur trains his ears to listen for any kind of commotion, but hears nothing.

"Well done " says Ilstur in a whisper "It seems that no one has heard this. We can go to fin that rat now..." 

He seems really worried that their quarry could escape.

Everyone, the hole you've fallen through is letting in enough moonlight to see the general shapes in the lower deck of the ship. You see crates and barrels scattered around, but no obvious exit save for the stairs leading up to the upper deck of the boat. Everybody make an Investigation check for me as you search for an exit, and the two humans please do so with disadvantage, unless someone lights a torch first.

Blue Investigation

4

Blue tips his hat at Zahira after she finishes the final spider, and begins to search around the boat  "I wonder if the child was lying? "