The RNLI said it expects the Shannon class all-weather lifeboat to help save more lives in waters around Ilfracombe, north Devon.
It is one of only two places in the region to get the upgraded model, which volunteers described as "faster and safer than its predecessor".
The new boat, called The Barry and Peggy High Foundation, also has a faster launching and recovery system.
It replaces Mersey class vessel Spirit of Derbyshire, which has performed more than 500 rescues over 25 years.
Suzy Tubby, an RNLI volunteer based in Ilfracombe, said the new lifeboat was an "incredible thing".
"It does 25 knots compared to the Mersey's 17," she said.
"The launching system is all very much quicker - then recovery takes less than half the time so it means we can be ready to go again a lot quicker" she said.
Second Coxswain Carl Perrin said he wanted to thank fundraisers for their help in bringing the new boat into action.
"It's faster, it's safer, it can go further and the potential for lifesaving is great," he said.

The pair, aged 24 and 27, were attacked by a group wearing hooded tops, who had covered their faces, on Drumilaw Way in Rutherglen at about 02:45 on Sunday.
The victims were taken to the Queen Elizabeth University Hospital.
Police said the incident was visible from nearby houses and have appealed for witnesses to come forward.
They said the men were approached by five or six male youths at the grass area opposite the Usave store.
Det Con Ross Philip said: "There are a lot of houses that overlook the grass area and roadway at Drumilaw Way and I'd like to speak to anyone who may have been disturbed by noise at this time of night and may have looked out and witnessed the two men being attacked."
Hospital staff said the men's injuries were not thought to be life threatening.
An upgraded £3m lifeboat has been launched in the south west.
[NEXT_CONCEPT]
Two men are in a serious condition in hospital after being assaulted in a large-scale disturbance in South Lanarkshire.