Do those "Bad Rope" messages consistently appear when a CastelF or Polacca model is around? What happens if you sail to another port, or go via worldmap to open sea; save game, quit, restart the game and load the savegame?
I'm not that sure the polacca does need to be slowed down, on the basis of two encounters during a new FreePlay game I've recently started as an outright pirate. The first act of piracy in this game was against what worldmap called "merchants with light escort", and which turned out to be, in sequence from front to rear: polacca, light pinnace, heavy pinnace of war (the latter being the "light" escort). Having recently visited Santo Domingo, I was still under a Spanish flag, and as this lot were French, they let me sail past them. The wind was about 45 degrees from directly astern - I don't remember the actual directions, but if we'd been sailing due north then the wind might have been blowing from the south-east. In any case, the wind was not from directly astern. Though the polacca was under full sail, and I was in a CastelF, I was easily able to overtake her. She'd opened up the gap ahead of the other, slower ships, which suited me. I raised the pirate flag and fired a salvo of grapeshot, the polacca raised the white flag, and I got to test out my new dialog for surrendered captains again.
By the time of the second encounter, I'd taken a tier 5 brig - faster than the CastelF with a wind from astern but not as good at close haul. I met a single polacca, with the wind blowing pretty much straight in our faces. The polacca was stupid; instead of trying to sail across wind, she tried to run directly away from me, which meant she had to tack, and each tack cost her speed. I sailed as close to the wind as I could, tacking a few times but not as often as the polacca, and eventually got into cannon range. A few broadsides of cannonballs then persuaded her to surrender.
I hadn't downloaded your newest file at the time I started this game, but I had set the CastelF to use the revised speed and turn rate, and set the Polacca to rig type "Xeb".