The sea gave up the dead in it: here the sea (see 10.2) is pictured as a living being, allowing the dead it held to go and stand with the others before God’s throne. Those who had died at sea were not thought of as going to Sheol, the world of the dead, but as remaining there in the depths of the water. If this kind of statement is not possible in some languages, the translation can say “Then the dead in the sea also went to be judged by God” or “Then … for God to judge them.” The same can be done for the next statement, Death and Hades gave up the dead in them. For Death and Hades see 1.18; 6.8. They are also spoken of as living beings (as in 6.8).
An alternative translation model for this verse is:
• Then the people who had died in the sea went for God to judge them. Death and the world of the dead gave up the dead people in them, and God judged them all according to their deeds (or, the things they had done).
Quoted with permission from Bratcher, Robert G. and Hatton, Howard A. A Handbook on The Revelation to John. (UBS Handbook Series). New York: UBS, 1993. For this and other handbooks for translators see here .