I think a double sink is desirable to some and not to others. It depends on one's preference. When we remodeled our home we installed a single deep and wide stainless steel sink which suits our purposes. It's especially nice when we entertain. We can fill the sink and soak dishes until we get to them. I should mention we have the advantage of having a dishwasher too.
In the 13' Scamp it's a totally different story. We have the standard white single sink. I do not know the sink's composition. Since I do want to keep it unblemished as long as possible I always use a plastic bin inside the sink when washing dishes or storing things in transit. Following is my protocol for washing dishes inside my trailer using minimal water and minimal space. This routine has come from many years of camping and backpacking. It is really a simple, fast process in spite of the number of steps. Supplies needed: eco-friendly liquid soap (Castille or Camp Soap is good), green "scrubee" cut into 1" square (toss it when done), 2 dishcloths (one on counter, one for drying) We find that blue paper towels found in car supply shops work well as dish washing cloths as they do not fall
apart when wet.
1. Each person licks or wipes their messy plate. (This step is only allowed in camp and is not tolerated when at home.)
2. Heat water for first rinse (or use water from cooking pasta, etc.)
3. Clean with liquid soap and warm water. Rinse the cleanest dishes first such as cups and utensils, then clean the more soiled dishes leaving the pots and pans for last. You can pour soapy water from cups to utensils to pots and pans (use green scrubee) since the water gathers in the tub.
4. Empty the tub of used cleaning water.
5. Heat rinse water very hot since it is used for sanitizing. Note: some people might want to dip their dishes in a mild bleach water rinse.
6. Rinse dishes, etc. in the same order as for cleaning.
7. Place dishes on towel between sink and stove.
8. Dry dishes and put away.
Note: When doing dishes outdoors it is nice to have 2 dishpans. You can dry the dishes by putting each person's place setting (dish, cup and utensils) in a net ditty bag and hang to dry!