Heat a slotted broiler pan in a pre-heated 450°F oven.
Pat the scallops dry and quarter them. Combine the vinegar, sugar, garlic and ginger and marinate the scallops for 10 minutes.
Arrange the bacon slices in a single layer. On each half-slice of bacon, place two slices of water chestnuts. Top with a scallop piece and wrap with the bacon, then secure with a toothpick. Repeat with the remaining scallops.
Place the scallops on their sides, exposed sides facing out. Draw the garlic and ginger from the vinegar and drizzle over the scallops, then bake for 10 minutes, turning once.