what is a shellback certificate?

its probably worthless to anyone but Michael Mortimer and his descendants as far as actual monetary value.

but intrinsically it's a valuable piece of Maritime History. .

http://www.shipspotting.com/modules/myalbum/photo-...

People have explained the Shellback thing already but I found this for you.

Here is a picture of the Port Hobart. It apparently was/is a cargo ship and this class of ship was built from 1940-1949. This Port Hobart was built in '46 so it is probably the Ship you are asking about.

And yes the Certificate is probably only valuable to the person that went through the initiation ceremony and maybe his family. There are other certificates for crossing things like the Arctic Circle, International Dateline, Antarctic Circle etc. etc. They are kind of a "Badge of Honor" to the people that went through the initiations (or a "Been there, Done that" statement).

Its probably worthless. A shellback as far as the US Navy and US coast guard are concerned is someone who has crossed the equator. Their is an initiation but all non-shellbacks aka scallywags go through this. All the certificates have the bit with neptune and davey jones. As to what Navy I am not completely sure but I know its a US custom not sure if the British do the same thing. As to the worth of it see if you can find out what ship it was from, some ships have been turned into museums.

The ceremony of "Crossing the line" is an initiation rite in the Royal Navy, US Navy, US Coast Guard, the US Marine Corps, and other navies that commemorates a sailor's first crossing of the Equator. Originally, the tradition was created as a test for seasoned sailors to ensure their new shipmates were capable of handling long rough times at sea. Sailors who have already crossed the Equator are nicknamed (Trusty) SHELLBACKS, often referred to as Sons of Neptune; those who have not are nicknamed (Slimy) Pollywogs.

The sailors are given a certificate and card called a "Shellback Certificate".

A Golden Shellback Certificate is for sailors who have crossed the point where the Equator crosses the International Date Line.

The Emerald Shellback Certificate or Royal Diamond Shellback Certificate is for sailors who cross at 0 degrees off the coast of West Africa (where the Equator crosses the Prime Meridian.

Submariners often become "Top Secret Shellbacks" having crossed the Equator at a classified degree of longitude.

Shellback certificates are awarded to Marines and Sailors who cross the equator while underway. Its a very old tradition. I couldnt tell you if its US or UK without looking. In the US it is celebrated by spending the day playfully hazing the new shell backs. People who have crossed before will spray new crossers with hoses and set up little challenges for them to run. It would only be worth a lot of money if it was awarded to a famous Sailor or somehow linked to something other famous. Other than that it is just something cool to have.