Christian charity Mission to Seafarers is holding Woolly Hat Day to cap off its ten-week national fundraising effort.
The Woolly Hat Day campaign has been endorsed by several celebrities, including Richard Branson, Dawn French and Griff Rhys Jones.
Rev Canon Ken Peters, the charity's director of justice and welfare, told Premier: "We are all dependent upon seafarers, particularly in this island nation of ours.
"Well over 90% of everything that we need - our food, fuel and raw materials - are brought to us by seafarers.
"They are isolated, disconnected from family and friends, have little or no support structure and they are out of sight, out of mind forgotten people that we depend on."
Mission to Seafarers provides emergency and legal support, methods of transport and communication, counselling and spiritual support for people at sea.
It works in 71 countries and 260 ports around the world.