Will this unit move a tandem axle pontoon trailer on gravel ?

Hello! Thank you for reaching out to Trailer Valet. Our units work best on flat surfaces, if you are to use them on gravel or grass, it would need to be compacted and not loose. If you are having any issues using it on this type of terrain, we suggest to use plywood to create a flat surface and add traction for you. If you have any questions please reach out to support@trailervalet.com or give us a call at 844 846 9344, thank you!