After all this work you guys owe me a great deal on a great watch!
"Take this quarter, go downtown, and have a rat gnaw that thing off your face! Good day to you, madam."
Hi Jim. Thanks for the fan mail 馃榾
That Master Mariner is very nice, especially with box and papers. The movement serial no. looks like it's a 1,207,xxx number, which would place it as a 1957 movement. So the watch itself probably dates from a year or two after that.
I don't think 87580 is the model or case ref no. Those were usually 4 digit numbers (often for snap back cases) or an E plus 3 digits - you might find it on the papers in the box. I've never been able to work out what those 87580 style numbers are...
I think it's a case serial number, but it could be a Longines-Wittnauer style number. I would need to see another identical watch.
gatorcpa