Problem? sizing stabilizer fins for the modern yacht hull form… creating fins large enough to perform both underway and at anchor without exceeding the hull envelope… or, keeping your OnAnchor™ or ZeroSpeed™ installation a two-fin installation instead of four… Solution! Quantum XT™ fins, patented innovation from the world standard for yacht stabilizers, underway or at anchor. XT™ fins extend to provide additional lift while in ZeroSpeed™ or OnAnchor™ mode, and then retract for less drag while underway.