Burro has what is often called "double hull" construction, in which the interior is formed from (often) two large gelcoat-finished half shells. In a sense it's lined with another (reversed) layer of
fiberglass. Simple unlined
fiberglass is quite rough on the back side. In addition, an unlined, single layer
fiberglass shell will have issues with condensation in cold weather, and heat gain in summer.
Other trailers with similar double hull construction include
U-Haul,
Cloud, later Parkliners,
Happier Camper, and
Oliver.
Happier Camper and
Parkliner use more than two interior pieces, but the net effect is the same: shiny gelcoat inside. Some have insulation between outer and inner shells; others do not.
Lil Snoozy also has smooth fiberglass interior walls but uses a completely different process in which two thin layers are bonded to an inner core of foam. It's not finished in gelcoat on the inside, so it doesn't have the hard, shiny gloss.
Escape and many vintage models (Trillium,
Boler, early Scamps, and others) are lined with vinyl bonded to a layer of closed cell foam, so there’s a semi-smooth, washable surface inside, but it's also not shiny like gelcoat.
My
Scamp and many other single hull designs like it have a soft material on the inside of the shell over the rough fiberglass with a layer of insulation under it, but all the cabinets are molded fiberglass with a gelcoat finish, so most of the surfaces you actually touch are easily cleanable. Scamp’s marine-grade hull liner is sturdy, non-absorbent, mildew resistant, and can be vacuumed or spot cleaned with a damp cloth. I too had always admired the clean, bright look of the
Burro, but when I actually got a first-hand look at the
Scamp I ended up buying, the so-called “rat fur” was one of the things I unexpectedly liked. It is pleasant to touch in all seasons, cool in summer and warm in winter, never sticky or clammy. Keeping it clean has not been a problem.
Like everything, there are pros and cons. Gelcoat is thin and brittle, and it can scratch and chip. Double hull designs are harder to repair in the event of fiberglass damage.