An olive boat is a serving dish which has been specifically designed for olives, typically with a narrow, oblong shape and high sides to contain the juices from the olives. Olive boats may be set out at buffets or on bars, allowing people to snack on olives, and they may also appear at the dinner table, typically during a Mediterranean themed meal. Many kitchen supply stores sell olive boats in a variety of sizes and designs, and sometimes different shapes are available as well.
As a general rule, an olive boat is made from glazed ceramic, which will not react with the vinegar in brined olives. You can also find olives boats made from plastic and enameled metal, but these materials can corrode when used for an extended period of time with brined olives, so it is generally a good idea to avoid them. Depending on the design, the olive boat may have a flush bottom, or it may have small legs or even wheels to allow it to be easily moved around the table.
The decorations on olive boats vary widely. Some are quite restrained, being glazed in solid, simple colors which blend well with a variety of tableware. Others are quite colorful, often decorated with paintings of olives and olive branches, and with bold stripes of color which are meant to evoke the Mediterranean. Some even have oversized ceramic olives interspersed in the bowl for decoration, and to fill the space in the bowl as people eat the real olives.
While an olive boat is generally oblong, they can come in other shapes as well. Some are wider, allowing people to put more olives in them, and an olive boat may be divided into compartments to separate different varieties. Others deviate from the oblong shape altogether, being round, square, triangular, and everything in-between. These shapes tend to be more unwieldy when set out with an assortment of other platters and dishes, while the slim oblong shape can be nestled between serving platters, creating less of a footprint on the table.
As a general rule, olives can be stored in an olive boat overnight or in the fridge, as long as they are covered to keep them from drying out. If you have mixed varieties in the olive boat, they may acquire new and surprising flavors if allowed to sit together, which is something you may want to consider. You can also add other pickled foods to an olive boat, like artichoke hearts, roasted red peppers, brined cheeses, and so forth.