The game seems designed around pirates, so I don't want them gone altogether. But the strength/frequency sliders are good ideas. Too bad you don't have a "both sliders, no switch" option
So I just voted for frequency instead.
A moderate frequency slider seems very reasonable. Between 10 and 20 minutes would be a good range. Or if they want to go overboard they could ramp it to a range of 5-30 minutes. Anything wider is just silly.