"Will you explain the detailed workings of this machine? What are we supposed to do with the strange knobs and sticks in there? What do we do in case of a leak, or if some other disaster occurs? It seems there should be some kind of training or something first..."

Is Darvin convinced?

Darvin shrugs his shoulders. "I'll probably regret saying this, but it seems to me nobody gets anything from anybody around here without these soul coin things, so I guess I'm willing to take a risk..."

Bazelsteen ushers Darvin, Drabash and Kaelani over to the bathysphere.  You climb up to the upper hemisphere of the sphere and enter through a portal.  As he closes the hatch he tells you "Secure yourselves inside and I will lower you into the river.  And as an added bonus, whichever one of you collects the most souls gets an extra soul coin!"

You find four “suction stations” inside the diving bell, each one equipped with a chair and some metal control levers.  You strap in at three of the stations as Bazelsteen lifts the sphere over the river and begins to drop you down into the water.  Tortured souls coursing through the River Styx claw and scream at the bathysphere as they pass by. You are lowered approximately 40 feet into the depths of the river which is so dark that visibility in the water is reduced to 10 feet. With the bathysphere lowered to the river bottom, you begin using the siphoning tubes to suck up the silted souls that lie there. 

Bazelsteen grins at Tibi as the sphere settles at the bottom.  "I'll give it about 10 minutes, that should be enough time to test the functions."  a gleam is in his eyes "We dine on silted souls like ambrosia. Silted souls can also be formed into lemures once they’re “rescued” from the river’s depths.  Sooo Tasty!"

Krikendolt nods his head in agreement "Oh yes! Very, very good!"

Kaelani, Darvin and Drabash I need 10 DEX rolls each please 

Kaelani straps into the beat-up metal chair, trying to ignore the fetid odor like month-old gym socks and sardines permeating the sphere...He looks over the controls, tries them out as they are being lowered, then settles in to the task at hand, maneuvering an external suction tube through the murky depths of the river of the damned to suck up tortured souls. Marvelous...

7 : 12 13 : 7 : 9 : 17 : 6 : 19 : 16 : 18 

Drabash also straps into a chair and gets a feel for the levers as they are lowered into the river. Once the Bathysphere has settled he starts to collect souls in earnest.

Dex rolls: 19; 3; 13; 10; 9; 11; 17; 8; 4; 14.

OoC: Checks or saves?

OoC: I guess it's the same bonus for Darvin either way: Jack of All Trades and Ring of Protection both give a +1. Darvin will also give Kaelani and Drabash each a bardic inspiration die (d8), should they want to use it on one of their rolls.

DEX: 22; 17; 7; 14; 7

17; 5; 9; 12; 10

6 - bardic inspiration for the '8' roll...

As the three inside the sphere do their best to collect the silted souls Bazelsteen stands at the controls and chats amiably with Tibi.  In the conversation Tibi learns that the sphere contains enough air for 1 person to survive for 1 hour.  Doing some quick math in his head he figures about 20 minutes of air for the 3 inside the sphere.  Bazelsteen  had said the test would only last about 10 minutes so they should have plenty of air.

About 10 minutes later a large commotion can be heard by the docks away from where the bathysphere is.  A f;ying fiend rushes over and Tibi overhears him say that a large number of Vrocks have attacked the docks and Bazelsteen looks over at Tibi and Krikendolt.  "I gotta take care of this.  We got time, it won't take but a few minutes to clear these vrocks off and I'll be back.  Keep an eye on things."

Before Tibi can protest Bazelsteen leaps into the air and flies away.

Those in the sphere have no idea what is going on at the surface as they work the controls and collect the souls. 

Not sure what else to do Tibi watches where the sphere slipped under the water. He waits for about five minutes to see if Bazelsteen returns. 

Standing near the controls of the crane that dropped the bathysphere into the water Tibi watches for Bazelsteen to return.  Krikendolt is not nearly as calm as Tibi is and starts to get anxious after a couple minutes have past.  "Is it time, are they out of air yet?  What can we do?  Pull them up!  Bazelsteen isn't coming!"

Krikendolt is not nearly as calm as Tibi is and starts to get anxious after a couple minutes have past.  "Is it time, are they out of air yet?  What can we do?  Pull them up!  Bazelsteen isn't coming!"

TIbi turns to Krikendolt "stop your caterwauling I'm trying to think here. Get Earwax out and go sit down over there and give him a cuddle or some such!" After five minutes have passed and there is still no sign of Bazelsteen, Tibi  turns to Lulu saying "how deep is the river? how long to get them back to the surface?" If Lulu doesn't know Tibi engages the crane and starts to pull the machine back to the surface once seven and a half minutes have passed.

Lulu flies over to Tibi.  "Shouldn't be more than half a minute to pull them up, maybe less.  Do know how to work the controls? Can we figure them out? I can't work them but maybe I can help?"

Tibi make an investigation roll with advantage

Tibi examines the various controls 16 and quickly works out what they do. He starts the machine operating and ...

Tibi starts working the controls and the seems to have them figured out after a quick trial and error.  The chain stiffens and he begins to raise the sphere out of the water.  As he does so a glabrezu lands on the barge.

The demon uses one of its pincers to try to snip through the bathysphere’s rusty chain.  11 10 22

At the rate the chain seems to be pulling the sphere out of the water it will take another 10 seconds or so of him operating the controls to get the sphere out of the river.

As Tibi works the controls the creature continues to try and cut the chain.  Just as the sphere breaks free of the water and he swings the sphere out onto the deck of the barge Bazelsteen returns and scares the demon away.

"Sorry about that.  That took a bit longer than expected.  Hope your fellows are ok.  You go let them out while I see how they did."

Tibi can fly up and open the hatch of the sphere while Bazelsteen checks the tanks.  

"Hmm, hmm!  Looks like the quiet one (pointing at Darvin) did the best."  He hands Drabash and Kaelani each a soul coin and two to Darvin. (added to inventories)

Soul coins are about 5 inches across and about an inch thick, minted from infernal iron. Each coin weighs one-third of a pound, and is inscribed with Infernal writing and a spell that magically binds a single soul to the coin.

Tibi borrows one of the coins and examines it closely "can't see what all the fuss is about" and then pulling out his decisionist coin continues "I think mine's better!"

"Well that wasn't so bad." says Drabash as he stretches after getting out of the bathyshere, I think I was starting to get the hang of those controls. "Now where's this dang machine that's going to get us across the river?"

Bazelsteen looks around.  "Oh yeah, the Tormentor.  It's over here."  You follow him back away from the river and closer to the docks.  Next to some short buildings are a few vehicles. "This one will serve you well.  I waterproofed it and you can use it to cross the river Styx.  They run on soul coins.  Those ones I gave you have 1 soul each in them and so will run the war machine for about 24 hours.  So use them wisely unless you have plenty more."

He then bids you farewell and heads back to the docks.

Kaelani inspects the vehicle, knocking on some sections and noting various dents and scratches. After making a full circuit, he looks at the others, shrugs his shoulders, and says, "Who's driving?"