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I don't use a float nor does the wire bend over the edge of the hole. That is why some/most un its have a transducer arm. The transducer arm hangs over the hole with the transducer hanging straight down the hole.
I just dangle mine over the edge of the ice. No worse than dangling it from a transducer arm. Been working for years now
The concern with just hanging the transducer over the edge of your case is it could get cut by a sharp edge of your DIY box (piece of rubber could fix that) the other problem is the transducer may not hang level if not straight down and the cord could freeze to the edge of the hole also . The Vexilar float..transducer arm and rubber stopper should work on your DIY box.
Thank you, humminbird did give me the foam float for the transducer when I purchased it, so maybe I'll try that but I like the transducer arm probably the best.
i bought a transducer arm for my Helix. the HB float would not set straight in the hole. My vex float did different kind of foam I guess/Keep it safe! JDL
Get a couple feet of 1/4 inch wire loom to slide over the transducer cable, it will prevent it from bending too sharp.
you can buy a marcum arm and stopper for less than 20$. lots of online stores sell them. seen one made out out of two closed end wrenches. there are aftermarket arms being made. i don't have links. a school is making them for non profit and link is in best ice deals lets hear em topic. theirs is aluminum and two engravings shipped for a 20 spot.when you use your arm, all you have to do is remove the air from under the transducer. so only less than one inch of it goes in the center of the hole.another way is drill dedicated holes for electronics and fishing. i use a triangle and fish the bottom two holes and sonar in top hole. you can let the transducer sit just below the ice plate and not worry about line cuts or tangles. be sure the transducer isn't touching the side of the ice hole or it won't point straight down where it needs to be.when scouting i use one hole and keep less than inch in the hole for marking and fishing.
Does humminbird sell one or did you get one from a different maker?
ask if it comes with hardware also.
I wonder if they supply the little beveled rubber grommet or whatever that goes around the transducer cord that fits in the end of the transducer arm like marcum has .
I like using the float like Uncut Angling does. He often lays the float flat on the ice and the cord hangs over the edge. When he's not using Panoptix of course.