A 40-year-liveaboard couple use their keels to dry out, dampen rolling, store fuel. They also have disadvantages, but poor windward performance is not one of them.
One person's list of characteristics for various types of cruising boat, as defined by their keels, with examples and advantages and disadvantages of each type.
The arguments for and against twin keels by a man who believes the arguments against are overblown.
Technical discussion of high-performance fin keel design, including foil shape, ballast configuration, sweep angle, end plates, etc.
This design firm specializes in designing and engineering composite rudders, trim tabs, and lifting keels, as well as "dolphin" keel bulbs to reduce draft without necessarily sacrificing righting moment and performance.