In 1896 Tony Anzalone, an Italian immigrant and previous US Navy sailor, made it his lifelong ambition to establish a tailor shop adjacent to the Brooklyn Navy Yard. In his early pursuits he spent his time adapting the fit of US Navy regulation uniforms in his tailor shop for sailors at the yard. Through his exploits the original design of the Seafarer bell bottom emerged. The design was eventually adopted by the Navy and over time 'Seagoing Tony', as he was referred, became a primary supplier to the Navy for the garment he had created.
Today Seagoing continues to market the Seafarer brand bell-bottom dungarees and shirts from its discontinued stocks from the late nineties and is in the process of introducing a new and improved version with many of the vintage features of the old style in order to keep its signature Seafarer design... The new Seafarer is due for introduction and rollout in Spring 2012.
Even better, rescued this text from the old Seafarer site using the Wayback Machine;
Seafarer brand clothing are made by Seagoing Uniforms, the military uniform division of Polkton Manufacturing Company of Marshville, N.C. who have manufactured military uniforms since 1896. Over the years products ranged from the "Dixie Cup" sailor hat to finely tailored officers dress uniforms.
Since 1946 and the inception of the Navy exchange system., Seagoing's focus is the manufacturing of the utility uniform. Seagoing is most noted for its original Seafarer brand denim bell-bottom trousers and chambray shirts which have served as the enlisted sailor's uniform for 60 years.
You can find these on eBay quite a bit, as below. No surprise they are on Rakuten too (above).