You could launch a boat with a keel like this, assuming you had an extendable tongue on the trailer, and a steeper ramp. Otherwise, as mentioned, you will need a crane something or other.
But a trailer like that that would work. an over the tire bed would be better for a bigger boat like you have. OR also as mentioned, something built into the frame and going up to the boat. Here is a link to my stepdads getting his boat he built off the ground, and onto his trailer. Boat is 9.5'wide. His trailer is similar to the one you showed, but a lot beefier as his boat is about 6-7000 lbs or there abouts. I would not want to tow this boat with a ford ranger, other than thru a yard to the launch "crane"