David Laskin wrote on 01 jul 2012 in soc.genealogy.jewish:

I have been trying to find out when a relative (who held a Polish
passport) left the US for Palestine in the 1940s.
...Is there any way to ascertain whether he actually
did this sailing -- for example a manifest of outbound passengers?...

The US did not even wanted to see departing passengers or their passports
prior to 9-11. So I doubt there was any registration.

The ship's manifests were probabliy only handed over to the local
authorities at the port of debarcation, nowadays called disembarcation.

--
Evertjan Hannivoort.
The Netherlands.
(Please change the x'es to dots in my emailaddress)