I sailed last month, and yes, ditch the sport coat/blazers unless you really want to bring/wear one, a majority of the gentlemen weren't wearing them in the MDR or at specialty dining. They wore slacks, jeans, chinos, collared shirts, t-shirts, and all manner of footwear (lace ups, loafers, sneakers, sandals)from dressy to sporty casual. The jeans I saw were of lighter color since we sailed in mostly warmer climates(Bermuda and Charleston), but again the a/c was on, and I was very comfortable wearing mine as well.