You need at least 50 ft if u get a hot fish and get him with the poon he decides to run under the boat and perform a crecent moon run the rope will keep him from getting away but not from jumping in the boat. Infact if the rope is to short and she has no where to go somthing bad is bound to happen. That's last thing I need when I am out there. A huge sword jumping into the boat " hot " will def do some damage. Flying gaffs in the head are great they seem to take the wind out of a well played fish. Some times u just have to take the shot early when ever u can so if she's not shy and comes up to take a look at the sword light. I am the type of guy that dosent like to let her go back down. No second chances no matter how live but she def is not comming in until shes dead.