More than 100 jobs are being cut at the Royal National Lifeboat Institution, with most of the job losses at the charity's headquarters in Dorset.
The organisation says its facing the "perfect storm" of a shortfall in funds at a time when more people need its help.
Ninety-five permanent jobs will go, alongside 40 temporary positions.
Ninety-five percent of its people are volunteers, mainly lifeboat crews and beach lifeguards.
Most of the people who work at the Poole HQ are staff, and more than 10% of those people will soon be redundant.
The RNLI says its cash reserves won't be sustainable enough to halt the jobs cuts.
Chief Finance Officer at the RNLI, Steven Peacock, says: "Free reserves are there to deal with financial shocks in the system, but that's not a long-term financially sustainable position to be in. So we need to take the difficult decisions now to ensure the financial sustainability of the RNLI in the future."
One reason the RNLI says it is suffering a shortfall is a decline in income from legacies, down from £131m in 2017, to £122m in 2018.
Sir Robert Syms, the Conservative MP for Poole says that although the redundancies are disappointing, Poole is well placed to offer alternative opportunities.
He says: "We've had unemployment figures that show we are well below average, there are more vacancies than there are unemployed in Poole. There are many companies who will interested in high quality staff and this organisation is a high quality organisation."
In a statement, Chief Executive Mark Dowie said: "It means we’re having to make some very difficult decisions. This includes proposals to reduce our staff by 135 roles, pending a period of consultation. The 135 positions include 95 permanent jobs, with the remaining 40 roles made up of temporary positions that won’t be extended or current vacancies that will not be filled. This is part of a programme of activity that, combined with increased investment in fundraising, is designed to help us get back to living within our means and deliver our world class rescue service across the UK and Ireland. The majority of the proposed redundancies will be based at the RNLI’s Support Centre in Poole as we look to focus on our frontline services and provide support at a local level."
Watch Richard Slee's report below: