The Düsseldorf show gets underway this Saturday, Jan. 20, with the largest indoor collection of boats of all sizes and shapes in Europe. Many of the boats introduced there by the larger builders make their way to the U.S. for the shows starting next fall; others just drop off our radar screens. But it’s always fun to see what’s being shown there, just to get some fresh ideas. Here are three that caught my eye, and they’re all very different. Steeler 50S TA, where the TA stands for Trans-Atlantic (pictured): A rugged steel and aluminum cruiser that the Dutch builder…