If Jonah knew he was the cause of the storm, then why not just jump off the ship, instead of requiring the sailors to throw him over?
I would say ultimately the way it played out God got the glory. We have been locked in a spiritual battle since the garden. Paul, does a good job of pointing it out. David was well aware of it when you read his words before facing Goliath and during facing him. Is just clear he is aware it is a spiritual battle.
Naaman is a good story to show the spiritual battle mixed with the culture and the beliefs of the time. After he is healed of leprosy he tries to to offer Elisha a gift. Which Elisha takes no gift. So anyway we can pick up the story in 2Kings 5:15-19,
15And he returned to the man of God, he and all his company, and came, and stood before him: and he said, Behold, now I know that
there is no God in all the earth, but in Israel: now therefore, I pray thee, take a blessing of thy servant.
16But he said,
As the LORD liveth, before whom I stand, I will receive none. And he urged him to take
it; but he refused.
17And Naaman said, Shall there not then, I pray thee, be given to thy servant two mules' burden of earth? for thy servant will henceforth offer neither burnt offering nor sacrifice unto other gods, but unto the LORD.
18In this thing the LORD pardon thy servant,
that when my master goeth into the house of Rimmon to worship there, and he leaneth on my hand, and I bow myself in the house of Rimmon: when I bow down myself in the house of Rimmon, the LORD pardon thy servant in this thing.
19And he said unto him, Go in peace. So he departed from him a little way.
They believed that a god inhabited everything. We oft think that when they worshipped idols that the idol was the god. The idol was a body a temple for the god that it would inhabit. So our God being the true God as the God of the Hebrews other nations would have recognized that he inhabited everything in that country. The mountains, wind, water, and the dirt. So Naaman becomes a follower of the true God and he ask for the dirt because he is gonna take it home. Spread it out and pray or worship on it as to him it is the very presence of God because he inhabits it as he has claimed Israel as his own and his possession and territory.
We see the same thing when the Philistines placed the Ark in the temple of Dagon. When he is fallen over and his head removed. It says that they do not step in that area even today. Reason being they saw that God had defeated Dagon so in that area it now belongs to him so they don't step on that area or soil as now the Hebrew God inhabits it.
So in ancient cultures their sea gods inhabited the waters and the waters would represent the mood of that god. Was he mad, at peace, and etc. So when Jonah tells them his God is the God of the Hebrews. In ancient times gentile nations on rough seas would have made some sacrifice to appease their god. Throwing that sacrifice overboard to the god. Which I am sure that proved to be futile to appease their false god. So Jonah being a servant of the true God. When he is cast over to appease our God. The calming of the seas would have been proof that the true God did also inhabit the very waters outside his country or territory. God would have shown in spiritual battle with other false gods that he was God of all and his power was not only in Israel but even outside of it. As he is God of all the earth and creation.
So while the story does not go into this I have no doubt that some of those there that day would come to realization that this strange God to them was in fact a God who had power unlike what they had seen. God would be known amongst those gentiles and he get the glory as the true God.