Article by Kate about new to trailering with a bunk trailer.
Got a solution - add a 2nd winch at the bottom of the winch stand, and winch the boat OFF the trailer via a pulley system tied to the rear cross member of the trailer 
Remeber, you still need enough water to float the boat from a shallow rampā¦
And for the real sharpiesā¦
Make a wooden āskiā for the ball/coupler to launch the boat in a shallow ramp with low tide, tie the trailer/boat to the truck with an adequate rope.
Launch my 17ā Triumph from alot of natural shoreline ārampsā 
Fishing the beaches, Bays & Ocean of Wildwood/Cape May, NJ
Soon a resident of Georgetown, SC
ā¦and for the real determined sharpie trailer boaterā¦
when faced with a soft sand covered ramp, or muddy āshorelineā ramp with excellent fishing nearby, sand boards are needed for placing under the trailer tires.
Also Alligator Beach Tires (black rubber/wide tires) are availble for the rich & determined trailerboater faces with a soft sand ramp. Not recommended for long distances however.
Fishing the beaches, Bays & Ocean of Wildwood/Cape May, NJ
Soon a resident of Georgetown, SC