dingy repair

We have been using this boat as a dingy for 4 years. Continuous dragging of the dingy up rough gravel beaches has taken its toll on the boat and rubbed through on the fronts of the tri hull keels. It is double hulled, so now water is getting in between. Is anyone aware of a process, or a...

Any idea what to do for a dingy that has been weathered and is starting to feel cracked a bit and looking rough?