suspension line length for a 12’ Bourd Type sea anchor?

[windseabob]

Does anyone have the suspension line length for a 12’ Bourd Type sea anchor? I got a good deal on a parachute from military surplus shop—but someone cut off the lines. So—I am splicing some new ones on. I did find a number on a skydiving hobbist website that said 1.5 times the diameter—which would be 18 feet. I thought that seemed long. Thanks for the help!!