No need to own a boat to get afloat, there are lots of boat owners and helms who need crew.
Racing boats of all sizes, whether a sailing dinghy or a racing yacht, are always on the lookout for crew so try your local sailing club website or give them a call. Many websites have a crew register where skippers and crew make contact.
If you are into cruising there are many different ways to get afloat. Sometimes it is for local estuary sailing, it could be crewing on a boat delivery or assisting someone with an ocean voyage.
There are also many charitable organisations who would love you to get involved either on large sail training ships, helping with disabled sailing, working with children or even the Olympics.
Racing
Yachting and Boating world is a website attached to many of the UK marine magazines. It has a forum with a crew search facility.
The World Cruising Club (WCC) is best known for the Atlantic Rally for Cruisers (ARC), the world’s largest annual trans-ocean sailing event and also organise many cruising rallies around the world. They have an active crew register for events and long distance cruising.
The Association of Sail Training Organisations (ASTO) and Sail Training International (STI) have many opportunities to get you involved. Their members operate all around the UK and overseas and take people sailing throughout the year and often their crew are made up with volunteers.