Lawrence Beesley thought that the forward boats were generally taken by first class, being in first class territory. The aft boats were largely taken by second class women and third class passengers of both sexes, who came up from aft. The second class were squeezed out. Here's Beesley---
"About this time, while walking the deck, I saw two ladies come over
from the port side and walk towards the rail separating the
second-class from the first-class deck. There stood an officer barring
the way. "May we pass to the boats?" they said. "No, madam," he
replied politely, "your boats are down on your own deck," pointing to
where they swung below. The ladies turned and went towards the
stairway, and no doubt were able to enter one of the boats: they had
ample time. I mention this to show that there was, at any rate, some
arrangement--whether official or not--for separating the classes in
embarking in boats; how far it was carried out, I do not know, but if
the second-class ladies were not expected to enter a boat from the
first-class deck, while steerage passengers were allowed access to the
second-class deck, it would seem to press rather hardly on the
second-class men, and this is rather supported by the low percentage
saved."