I am generally really good about getting water of my cover when it rains, but I was out of town this weekend and the weight of the water caused my tm blade to poke through it. Would it be a better idea to sew it, or use a glue like liquid thread?

I had similar problem......I would use both, sew it up and then glue the threads...and get a prop cover for the trolling motor to prevent it from happening again

Thanks I guess I will be heading to BPS today, I didn't know they made prop covers.

Put an old towel or cloth over the propeller when covering your boat. It costs nothing, and will do the job just fine.