Hi, I have a 1989 Spectrum 1700 with a 85hp force OB. I am interested in installing a Ski Tow to pull tube for my kids. I am having problem as I heard people said that I cannot install ski tow with a Out board. the only choice I have is to install a Ski Pylons. is that true? if not. do i need to install 2 ski tows so that the rope is balance in the center?