Around here it is usually referred to as a beaver tail rather than dove
tail but same thing.

If you mostly do vehicles, you will like the beaver tail, much easier to
load. Most vehicles have some sort of rear overhang, you need the
trailer there to attach tie downs but level is not important. If you
mostly haul steel or lumber, the beaver tail is a pain. You need to
support the ends of the steel/lumber, you can't load pallets on the back
end.

We load a race car with full ground effects fairings on the front and 3"
of ground clearance in the middle onto a flat trailer. I have to pick a
good spot to load it, set up long ramps, then add some strategic 2x10's
and assorted blocks to get up 18" in the air.

Sounds like you want the flat version, just bring along some extra
planks for low slung cars. Hint: put a 5' long plank with a 2x block
under the ground end of the ramp, makes it a lot easier.

Albert wrote:
I'm thinking about getting an open trailer for general hobby use
(hauling steel tubes, dimensional lumber, an occasional machine, and
an occasional car). I'm thinking tandem axle, electric brakes on both
axles, 18' long, and 7000 to 10000 pound GVWR. I've seen many of
these with a slanted dovetail on the rear-most 4 feet. I understand
this dovetail combined with 2 short length ramps make it easier to
load a low clearance vehicle. But I don't understand why a flat bed
and 2 long ramps wouldn't do the same job. Do long ramps bend
easily? Are they uneconomical in terms of cost and weight compared to
a dovetail? While they might be good for loading a car, I don't see
them helping if I'm carrying long tubes or wood.

Also, I've considered an enclosed trailer but have yet to see any with
strong tie-downs that would be appropriate for tying down a machine.
And they sure are expensive.