Extreme sailing is really big, really fast and really scary - but that doesn't stop Newsround fans Ella and Lily!
The girls have spent their summer holiday sailing around the UK coast.
They've agreed to take Hayley for a ride on a super fast boat from the Extreme Sailing Series competition on the Isle of Wight.
It's called the Extreme 40 and can reach speeds of 40 knots - about the same as 45mph in a car!
Hold on tight, Hayley!