Make the Ocean Rough

Be close to the water when you do this, like on the deck of a launch or in a canoe etc.
You can do this spell in your mind, but it also works saying/whispering it. If you are on a boat and don't know the captain's name, just do captain.

"I command that the sea is harsh and difficult,
to make it hard for (captain boat/launch or youcanoe/kayak)
to get through.
This is my wish,
So mote it be."