As a former dealer owning hydraulic and fixed welded supports trailers, a lot depends which trailer to use if launching and retrieving without the use of a travel lift.
Fixed support beam trailers either have bunk boards generally found on trailerable boats that sometimes include side supports with bunk boards or with screw jack pads. Most of these boats have swing, shoal draft or a fixed fin keels. However, some boats for example the Catalina 22/25 wing keels and Hunter 23/270/27 wing keels all have trailers designed around wing keels which can be trailer launched by tow vehicles. There are larger trailers too for carrying heavier and bigger boats of this style too. However, the length, width, depth of water at the end ramp, wind speed and tidal current all play into the mix during launching/retrieval operations. This incudes trailers designed for the wing keels too. With my larger boats, I launched with heavy duty trailers at Kerr Lake that had a very long ramp that could. accomodate launching of boats up to 45 feet; however, I restricted myself to launch up to 33 foot wing keel boats due to width of the wings plus gross weight. Anything over 26,000 pounds requires all vehicles to be treated as commercial with the driver having a commercial driver’s license or CDL. Due to the construction of a hydraulic trailer being much heavier, I was restricted which sailboat I could haul keeping the gross weight under 26,000 pounds.
As stated, hydraulic trailers are much heavier but the side supports are hydraulically raised or lowered. When lowered, there is no issue of how wide the wing keels are but the above issues still could come into play.. With the fixed support trailers required me to have a very long extension dolly that had to be manually guided into the water and once stopped the rear supported screw jacks had to lowered even if the water was icy and cold which was part of my duties.
The poster has a very good question and
@Art12050 recognized the issue
I hated the icy water as it was Cold and only Crazy Dave was crazy enough to do it.
I even have launched sailboats over embankments and bridges; however, that is not suggested as only a few of us ŵere experienced requiring the utmost safety in the industry