Were those who perished in the flood of Noah eternally damned? The following passages from Genesis led me to think that all who perished at the time of Noah were cast into Sheol to await the great white throne judgment.
Gen 6:5-7,17 KJV

5And GOD saw that the wickedness of man was great in the earth, and that every imagination of the thoughts of his heart was only evil continually.
6And it repented the LORD that he had made man on the earth, and it grieved  him at his heart.
7And the LORD said, I will destroy man whom I have created from the face of the earth; both man, and beast, and the creeping thing, and the fowls of the air; for it repenteth me that I have made them.
17And, behold, I, even I, do bring a flood of waters upon the earth, to destroy all
flesh, wherein is the breath of life, from under heaven; and every thing that is in the
earth shall die.

What do theologians say about it?
Interesting that it is that passage that leads you to the conclusion that " all who perished at the time of Noah were cast into Sheol to await the great white throne judgment". I say that because there is another passage which explicitly agrees with your conclusion!


  For if God did not spare angels when they sinned, but sent them to hell, putting them in chains of darkness to be held for judgment; if he did not spare the ancient world when he brought the flood on its ungodly people, but protected Noah, a preacher of righteousness, and seven others; if he condemned the cities of Sodom and Gomorrah by burning them to ashes, and made them an example of what is going to happen to the ungodly; and if he rescued Lot, a righteous man, who was distressed by the depraved conduct of the lawless (for that righteous man, living among them day after day, was tormented in his righteous soul by the lawless deeds he saw and heard) – if this is so, then the Lord knows how to rescue the godly from trials and to hold the unrighteous for punishment on the day of judgment.


2 Peter 2:4-9

We don't know for sure if they were eternally damned - only that they are being held for judgement. However, it is logical to think that they were / will be damned because they are being "held for punishment" and because they did not go to heaven when they died.