Interesting. In real life if you foul and anchor and have to cut the line you might leave a fender floating there so you can come back later and try to retrieve it. This might be an option in those days too, for example using a barrel to mark the location. So if you can run to fight in game you wouldn't necessarily lose the anchor, you might come back and get it later. Obviously this depends on the size of the ship because it's one thing to hold modern chain and rope with a fender, the chain and rope in those days probably weighted a lot more. Assuming they also used a mixture of chain (for the weight where its needed at the bottom) and the rope then it the only thing the float would have to support would be the length of the rope measuring the length o the water depth (obviously the chain/rope combo would be much much longer, but most of it would lie on the seabed and not pulling down on the float).