Old salt and Oldtimer

Old salt noun - A man who serves as a sailor.

Oldtimer and old salt are semantically related In some cases you can replace term "Oldtimer" with "Old salt", this terms are similar.

Oldtimer noun - An experienced person who has been through many battles; someone who has given long service.

Old salt and oldtimer are semantically related in particularly in war topic. Sometimes you can use "Old salt" instead a noun "Oldtimer".