Lifeboat crews had their busiest time ever in 2005, with 8% more call-outs than the previous year.
The south coasts of England and Wales are the RNLI's busiest areas
Most of those rescued were on pleasure craft and a growth in water sports is one reason for the rise in emergencies.
The Royal National Lifeboat Institution (RNLI) said its lifeboats were launched 8,273 times last year compared with 7,656 in 2004.
Its busiest areas were the south-west of England and south-west of Wales; Poole, Dorset, was the busiest station.
The number of launches rose there by 16% and 15% respectively.
RNLI operations director Michael Vlasto told the BBC News website: "There is an increase in rescues especially during the months of June, July and August which reflects recreational trends.
"As a result the season grows ever longer as people want to get out on the water more and more."
Mr Vlasto said the coasts of the south west of England and Wales were "by far the busiest" rescue areas because of the number of leisure boats based around those areas.
They were also havens for water sports enthusiasts, he added.
At Poole there were 147 launches - crews there rescued 145 people in distress during 2005.
The RNLI relies on donations for funding and Mr Vlasto said it was "arguably the most reliable and professional lifeboat rescue service in the world".