I bought a used boat from a guy about 3 years ago and never got the trailer registered in my name. What is going to be required to get it registered in my name. Will there be penalties that I will have to pay?

Trailer registration is managed by TxDMV, not TPWD. Key question is has the trailer been previously titled or just registered, or neither. Trailers only have to be titled if they are greater than 4000 pounds gross weight. Best thing to do is to track down the owner on record and have him/her sign the transfer documents, form 130-U. Regarding late fee costs, the 130-U form shows a 5% or 10% box if application is received after 20 working days of sale. Website shows significantly higher fees that continue to accrue with time. Better give them a call first.

I will add this - please don't sell your integrity and falsify the documentation. Not only is it illegal, it is also the wrong thing to do.

If you do get the proper documents from the previous owner. On an untitled trailer I think you just need a signed bill of sale and the old registration info. When they ask just tell them that the trailer has not been on the road since the registration expired.

Maybe I'm a terrible person but I'd fudge the date on the document and not pay the late fees. I'm okay with paying their taxes and know it is the right thing but I don't mind dodging late fees. Sorry if that means I'm terrible. If it was 10% that's one thing but I believe it's a lot more.... at that length of time.