Shipped on board and clean on board bill of lading

I would like to explain the difference between shipped on board bill of lading and clean on board bill of lading on this page. 

The reason I would like to write about this topic is that some issuing banks demand "shipped on board" bills of lading, whereas others demand "clean on board" bills of lading under "letters of credit" payments.

Exporters are getting confused, when carriers issue a "shipped on board" bill of lading where the letter of credit requires a "clean on board" bill of lading or vice versa.

What does shipped on board mean on a bill of lading?

Bill of lading is a traditional transport document, which has been issued by the carriers for sea shipments that has been taken place between one sea port to another.

Historically, there are two main types of bills of lading available on the market in terms of scope of issuance.

• Received for shipment bills of lading 
• Shipped on board bills of lading

Today I would like to explain the meaning and function of an on board bill of lading and received for shipment bill of lading.