A boat lift that pumps air into a ramp—using solar power.
Panels can be added for larger boats.
A Jet-T for Jet-Skis:
http://www.safehavenboatlifts.com/products/jet_t/
Video for larger boats (3500# to 4500#) at this link:
http://www.safehavenboatlifts.com/pr...treat_2_solar/
Looks like it would take seasonal lake heights in stride.