I made an interesting discovery the other day.
I am in the process of moving to a different home about 25 miles away.
The fastest least bumpy route between the old house and the new house happens to be a toll road.
Both of my cars have a device known in Pennsylvania as an EZPass which permits me to use the automatic toll lanes on the highway.
As per instructions I have the device mounted on the windshield directly behind the rear view mirror.
While transporting two of my canoes down to the new house on the roof top of my cars - one canoe per car, the toll both had no problem detecting the EZPass through the Kevlar canoe but could not detect it through the graphite canoe.

Has anyone else had this experience?

I'm wondering if a similar issue would occur with a transponder on a fish locator trying to read through the hull of the graphite canoe.

The Kevlar canoe is an 18' Wenonah Sundowner.
The graphite/Kevlar canoe is a 14' Bell Wildfire.

I had an EZPass exit issue with an Old Town Discovery (getting on was no problem); but no problem either way with a carbon/Kevlar Northwind. The Disco has aluminum gunwales (iirc) and the Northwind has wood.

Yes, the ezpass can be tricky when you have boats sticking out all over. It seemed to me different states had different locations of scanners. New York was the trickiest for me. I'm not sure it worked well going through Chicago either. They don't really let you know if it worked or not and it's not like you get a print out of activity. I do know it's much cheaper to use it vs paying cash.

This was my initial load. I learned to not pull up to far right away when a gate almost wrecked a boat when it clipped it. And it can be tricky to get the ezpass to work. Those surf skis are like five grand apiece.

I think its the scanner location. I too have a WildFire and sixteen other carbon or kevlar or royalex canoes.

Yet not had a problem . I have not used our EZ pass in PA though.. I think I have hit all the other states that have it. With boats.

I tried pulling the device from the windshield and holding it up in a position not under the canoe and everything worked fine at that point.

I do know that if it doesn't register a photo is taken of the license plate. The plate number is then compared to the ezpass database. If the plate is registered there then the appropriate toll is debited from the account just as if it had registered. I checked my statement to see.