As we have seen, The Bethel Society maintained a private organization that brought religion to various Merchant Ships and Sailors on The Seas in the 19th Century, They identified themselves with The Blue ''B'' Banner. However, most Navies maintained a similar practice on their Warships known as The Church Pennant.
It's development can be traced to The British Royal Navy ans The Anglo-Dutch Wars of the 17th Century. The Navies of both sides would hoist flags with a Cross image at certain periods. This was to signify that religious services were being held (by a Chaplain). No combat or attacks were allowed by Military Code. In time, The Royal Navy adopted a permanent style of Pennant which is raised off the vessel's super-structure on Sundays or another important religious date. No combat or training is to be conducted while The Church Pennant flies.
The Royal Navy version features a Red, White and Blue swallowtail extension located at the Fly of The Pennant. The Canton to the Left is a White Field with a reclined Red Cross. This is to symbolize The Anglican Church (the only recognized and official religion of a British Warship).
In The US Navy, the adoption of Church Pennants did not come about until the end of The American Civil War (1865). The official Pennant is a solid White Field with a simple Blue reclined Cross. It is flow for all forms of Christian Service. In 1975, The US Navy authorized the flying of a Jewish Service Pennant (also in White), with a reclined Blue image of The Tablets of The Books of Moses topped by a Star of David. Currently no other religious denominations (although allowed) – have their own distinctive Pennant.
Many other Navies ceased the used of Church Pennants, citing that they could be use as a form of deceptive combat tactics. Regardless, most Navies honor both The British and US Pennants.