Charlie, its amazing that I thought of two of your suggestions.

some more ideas.

There is a chemical that is used in riot control that is super duper slippery. It might be of help.

Cannon ejected netting with a anchor that is dropped once the pirate boat is snared.

Call to muslim prayer music can be played at the correct hours.

Large hinged plates can be released from the side of the ship that would sandwhich pirates climbing up the sides.

localized electrical shocks can be discharged on the hull.

Throw counterfeit money over the side.

Put diamonds in smoe commercially valuable fish to increase the fisherman to fish instead of pirate.

Project holograms of muslim Clerics telling them to go away.