Here is the original trailer tongue/hitch as supplied by Harbor Freight for their 1950 lb tilt trailer. With the boat loaded appropriately, the bow prevents the car truck from opening! And needless to say their is no way the boat would float on/off the trailer with that tongue. So here is what I did…

I removed the carrier.

Then inverted it to re-use the square tube. It is now parallel with the bottom of the frame members. 
All bolted up below.

Then I took the 2″ square 3/16″ wall tube I bought and inserted it into the tube and added 2 U tube brackets on the bottom of two frame members. This locks the new square tongue from lateral movement, but allows it to slide fore and aft.

Photo from the back showing the captured tongue and U brackets.
Got my decal/sticker numbers for the registration in the mail...

Here is the new towing position. It is 3′ 6″ longer that the original.

And below is the new launching tongue length. 7′ longer that the original! I sure hope this will allow me to launch and retrieve the boat without submerging my car! If absolutely needed, I COULD drill another hole for another 4′ of length, but the 2″ sq tube would only be guided by the red tube in the front. That red tube is 2 1/8″ by 2 1/4″ so the 2″ sq tongue is a little sloppy, though not as much as one might think. Might work for launching OK…

I have also drilled a 1/2″ hole vertically through the red trapezoid at the head of the original trailer carrier mount. I have a grade 8, 1/2″ bolt to drop through to lock the tongue in the towing position. I will add a 1/2″ hole set to lock the launching length as well. Thought I took a photo of that, but I cannot find it now. There is more to be done, but more later.
Un Abrazo,
Bill