Of all the Columbia sailboats I think the Columbia 50 is the most similar to the Columbia 43. They both have the same designer, the dimensions are suspiciously similar (the beam is the same on both, the waterline length is only one foot shorter on the 43 than the 50, the draft is nearly the same and the standard interior layout is nearly the same).
The boats were so similar, in fact, that Columbia Yachts could use the entire deck, including the house and the cockpit, from a C-50 on the C-43 hull number one . They just had to trim around the edges.
Here's wishing Kevin well on his new endeavor. Be sure and check it out.