Theres actually a thread on this subject. Link below. I will see later if I can find the charts I was looking at. There was a differance but it wasn't as large I was expecting. But in relation to my lifeboat curiousity the data might be apples an oranges. I think you would have to take in other factors that might skew the data. For example people who go on vacation on cruise ships today probably don't look much like the people who go vaction to climb Mt. Everest or shoot the rapids down the Grand Canyon. So the people on cruise ships might tend to favor more on one end of the scale than the others. But overall if I remember right the average between 1912 and 2012 was only like 10 lbs differance. I remember I was expecting it be greater.
I recently heard that James Cameron built his Grand Staircase larger than the original so it was in proper porportion, as people "are larger" today than in 1912. Does anyone know what the average height & weight would have been for man and woman in 1912?