Friendly-to-you pitbull? Pest control flash-bangs? Home-brew Mustard gas? 106mm howitzer? Pet shark? Rattle snake? Punjii stakes? Accordion music...better yet, a recording of bagpipes playing 24/7 while yer away. Oughta scare the begeezus outta 'em. Spill a bottle of Rum in the cockpit?
Nah! Just kidding..... really !
Call Attenborough an' tell'im ta come get his cute little critters the he11 offa yer boat!