You can under FAA log PIC time if you are flying with an instructor (most all FAA RW pilots have a FI).
I know that people also log s-61 time as SIC time without typeratin doing logging work.
They can not log PIC time until they have the type rating though.
I am not sure if this is right or wrong, just know that it is being practiced.
So I have a question then:
If you work as a logging co pilot in Alaska on the S-61, and you log 1000hrs SIC, would those hours count in the JAR world?
Would you then be an "experienced" multi engine multi crew pilot?
After all, you log the hours under the regulations of the country you are flying in?