There was no systematic registration of seamen. There are however some muster rolls dating from 1747 to 1857 in BT 98. These are incomplete and are based on the port of registry and the date of sailing. You will also need the name of the vessel.

You may find details of seamen through other types of records, most commonly records relating to trade, taxation, legal disputes and the Royal Navy.

Merchant shipping: Crew lists and agreements, 1747-1860

My Ancestor was a Merchant Seaman, Second Edition, Christopher T. Watts and Michael J. Watts (Society of Genealogists)