I have been meaning to write something about the ocean goddess Darmala. She is a complex deity representing the ocean, peace, anti-government sentiment, motherhood, piracy, alcoholism, looting, stealing, fighting, and spirituality. She is also the god of sailors and can be felt in all water to an extent. She can grant her followers a natural affinity and skill towards spirituality, meditation, anti-government activities, sailing, fighting, using guns and cannons, stealing, or generally causing chaos. In some cases she can also grant impunity from the law or a fruitful catch during fishing.
To connect with the Lady of The Waves, try researching piracy, the ocean, or marine life. You can also look into more esoteric concepts like deities of the ocean, worlds of the ocean and demons with a water aspect such as lord Leviathan.
Besides that, you can give offerings of seashells, rum, swords or weapons, or valuable items such as coins. You can also give offerings of food such as meats, fruits, vegetables or even flour since hardtack did not go bad on ships. Even blue candles or paintings work for shrines and can be used in spiritual workings to help connect you to the ocean.