I use a huge custom made rope cutter from http://www.prop-protector.co.uk Who now have an US distributer. What I first had was a rob cutter with a 50 mm blade. It Probably did the job (except for a cement bag I picked up in Mersin) except it seemed puny. Since they seem to make their special order ones by hand (probably out of China), I asked if I could have one with a 150 mm blade. It took MONTHs to arrive and when it did, the yard looked at it and said "whoa" and as it was two piece, installed it. That was 5 years ago and during this last haul out, I replaced it with a new one, abd took the now dull one to my machinest who machines a new cutting blade at about 145 mm. That is now in stores. Lee