Hey anglers I have recently joined a mini boat and tube league to compete this season. I was wondering if you guys had any advice on how to keep the fish alive until weigh-in. The only thing I can see is tying a stringer to my tube?

Check with some of the other "tubers".

 

 

You can get a plastic basket similar to this.  Set it in an inflated bicycle tube (find the best size tube) and secure a top to the basket with a chute for putting fish in the basket.  Attach it to your belt, or float with a short lanyard, and you're good to go.   You can attach the tube to the basket with plastic wire/zip ties.

 

Make the top out of a piece of plywood or plastic.  You need the chute to prevent fish from escaping while trying to get another fish in your "live well".  You can hinge a door in the top with a clasp to take the fish out.  The chute should be installed as part of the door.