OoC: Yes, the ship is armed with two ballistae, one on each end.
Thamior, Marques, and Warden head up the main mast, armed with the light crossbows (OoC: I presume you're giving them the light crossbows?). The three make way for Katherine as she joins them.
Ricardo takes the helm, and the ship slowly steers towards land; soon enough, the shore is coming into sight. The shore is quite rocky, and it seems that if the Gazelle were to get too close, she would be broken upon them.
"Green an' grey!" Warden calls down.
Ricardo nods. "Aye, they be workin' alone, miss..." He calls up. "They be no colors I reco'nize. I'll be slowin' her down, we don't want to break up on th' rocks..."
The ship gradually slows, and everyone can see the pirate ship clearly now, closing in from starboard. From your places on the ship, you can make out shapes of men and other humanoids on the approaching craft, and they appear to be readying what seem to be grappling hooks.
It will be upon the Gazelle in a few moments...
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Initiative and actions, please.