Does anyone have a better way to make the Alps Mountaineering Weekender Seat work better in a canoe with bench seats?

Our group picked up 5 for our trip this year and by all accounts they were worthless, offering no back support. No matter how tight we had them strapped on to the seat, or how tight the adjustable side straps were, they would just slide towards the back of the seat and fold over.

Alps Weekender Seat

I have a GCI chair that doesn't stay tight in the canoe. Looking at the straps I believe the problem is that the webbing coming from the front edge of the chair isn't quite long enough to allow the buckle to lay flat on the plane of the straps under the chair. Ladder lock buckles usually require tension on the same plane that the straps travel on, and anything else will cause the strap to slide and loosen.
If your issue wasn't with loosening straps but instead the chair itself was rotating around the chair, then you should let ALPS know that perhaps you found a design issue with their product. There's no stays along the side edges of the seat to help it keep it's shape?

It could be that they're just too wide (front to back) to snug up on the seat correctly. If they are wider than the seat there's not really any way to fix that.

jhb8426: "It could be that they're just too wide (front to back) to snug up on the seat correctly. If they are wider than the seat there's not really any way to fix that. "

This is exactly what I found when I tried them. You could try a mod to prevent the Weekender from sliding back on the canoe seat, but other than that, the design is not really compatible with most canoe seats.

I had same problems with different brand of the same seat.
I found tightening the side straps ony brought the top of the back in further, closing the angle of the back and seat. No lower back support and as you said the seat would slide to the back and hang off the back of the seat.

Really is a difference between canoe seats and bleacher seats I believe.
My solution was to switch to GCI Sitbacker.

YMMV

Blue Skies!
cc