Re: Not so cool weld job
in my very unprofessional opinion, you need a whole new tongue properly sized and welded to replace the improperly sized and improperly welded piece you have. If you have a family member who is a welder your looking at around $100 in parts and $30 in Beer.
Use an angle grinder to remove the old piece and prep the remaining, the rest is up to your welder, he is looking at about 30 minutes of welding time total.
If you are interested I would look at getting some 3/16" thick 6"X12" flat stock to make some good gussets with, probably add 10% to the total strength and clean up the joints where the trailer mains meet the tongue. Grind it clean and paint, twice.