Sailing across the Indian Ocean was the first time we’d come across large drift net fishing. I suppose that the best way to deal with them is to give them a wide berth, assuming you know where they are located.
The yachties ahead of us reported known positions of drift nets on the daily cruiser’s net, and we made notes of these positions. That said, they were usually not there by the time we arrived a few days later. Some drift nets were reportedly marked by buoys, some lighted and some not. The best one could hope for was to see them on a moonlit night. Some fishermen remained close to their nets and advised oncoming traffic by radio of how to avoid their nets. We had this happen one night, but the fisherman could not speak enough English to tell us how far out his nets were laid. We were told by some yachties that the nets were usually set to windward of the fishing boats, but we could not confirm this was the norm.
We’ve never had the misfortune of becoming entangled in nets. I’ve picked up the odd fish trap or lobster pot over the years, but managed to cut them free without too much drama. I can’t imagine trying to cut free of a net in the middle of the ocean, in the middle of the night, in a seaway. We did hear a horror story about a yacht lying in Salalah that had become entangled in a net. The weather was heavy, and for whatever reason they were unable to strike their sails. They ended up with broken sails, broken gear and apparently some other damage to the yacht and had to return to port for repairs.
I suppose we would have to assess the situation if we were to become entangled. If we could safely do so, we’d strike the sails and I’d get in the water and try to cut us free. If we could not, we’d have to heave to or drag the net until conditions allowed. Hopefully there would be enough sea room. Some boats have line cutters installed on their prop shafts. I don’t know if this would allow them to mow through a drift net, but it is probably helpful if one runs into a fish trap, lobster pot or a bit of stray line floating on the surface.
At the end of the day, the only defense is constant vigilance and a dose of good luck.