Ok, so in Texas, a boat is not required to be registered if it is under 16' and unmotorized. So my question is:

Take a 14' Jon boat--with no motor it doesn't need to be registered. So if you add one of those clamp on, transom mount trolling motors, would that make it "motorized" and therefore need to be registered. That would seem silly to me.

And if it does require registration, what are the penalties if not registered?

In Virginia you have to have it registered  if you have a trolling motor, because it makes it motorized.  I would assume that the definition for motorized is the same in both states.  I thought it was dumb rule too.  I got a warning from a park ranger and I had to get it fixed before I could use it again, otherwise I would be given a ticket.

I'd check with the Texas Parks and Wildlife just to be safe. They should be able to answer any questions you may have as well as send you any information of forms you would need.

For Maryland, my 16' jon boat needs to be registered. It's free unless you have an outboard that is 7.5HP or larger.

In Texas, when you put that trolling motor on it, it has to be registered and the numbers have to be on it. If your caught, you will at the least get a citation, and you will have to remove the boat from the water. They can also confiscate the boat since you can't prove ownership. Those TPWD tickets are not cheap either, you probably are looking at at least a couple hundred bucks if not more.

I'm out on the west coast and fish fresh water from an electric powered home built kayak. The motor is 1/2 hp (MK40) and easily removable. Oregon and CAlif require that any powered boat must have a Hull Identification Number (HIN) on the stern, and state registration numbers on the bow. It is a bit of a hassle to get the paperwork done here but after one time around it is just a 2 year renewal deal.

I'm sure Texas is not as tight as these folks, but keep in mind that local governmets are hard pressed to keep their cash inflow  up with their spending, and you don't want to become part of their solution to the problem..

I got a $50 ticket at Loxahatchee, FL for not having vessel registration. My boat is a 9' BPS Pond Prowler with a Minnkota Endura 30.

Here in Idaho you have to register a kick boat if you put an electric motor on it.  I would guess that it would be a the same elsewhere.

May I suggest playing it smart and registering your watercraft unless the state tells you otherwise.

If the craft is stolen or damaged you then have proof of its existance.

It is better to be safe than sorry.  

I got a $50 ticket at Loxahatchee, FL for not having vessel registration. My boat is a 9' BPS Pond Prowler with a Minnkota Endura 30.

Same boat, same motor. Georgia requires it so I picked up a registration form from Wally World and mailed the DNR a $15.00 check for 3 years. Just keep the registration stub in your tackle box. REALLY cheap if you ask me.

I had to go to DMV and get a formal vessel registration (around $40), then get the stickers with the registration number and put it on port and starboard sides.