I don't use big boards any more but back when I dit I just used the metal pear shaped shower curtain rings and the rubber bands that's made for the band buster releases. they are red in color and rated at 2 lbs I believe but they are the light weight rubber bands. you can pick them up at most bait shops around the great lakes. they have 2 weights heavy and light and for most fishing the lite ones works best. just let out your line then loop the band around your line and pull it through its self and pull it tight. then put it on the curtain ring and snap the rind closed over your board line. then just feed out line and it will slide out as far as you want to go. as you catch fish or change baits the rings will just slide out your line and stack up at the boards. just have extra rings. the rubber bands are sold under the name Weldon tackle. you could probably do a search for Weldon tackle trolling rubber bands and find them.