Source: The Great Interpretation of Dreams (Ibn Sirin)
A raging sea in a dream indicates great strife and affliction, or an unjust, oppressive ruler. Riding it indicates entering a dangerous matter. Escaping from it is salvation from hardship.
Source: Perfuming Humanity in the Expression of Dreams (Al-Nabulsi)
A raging, dark sea indicates strife and affliction. It may indicate fear and hardship. Whoever sees himself struggling with its waves is struggling with worries and horrors.
Source: Signs in the Science of Expressions (Ibn Shaheen)
A raging sea is interpreted as an unjust king. Whoever sees himself drowning in it will fall under the king's oppression.