The RNLI is aiming to double its 250,000 membership as part of a new fundraising and marketing strategy to combat falling reserves and rising costs.
Richard Popper - who became the charity's head of central fundraising and communications after joining from Zurich Bank in May - will oversee the strategy.
The central marketing budget will rise by 25 per cent to £9m, and new fundraising methods will be implemented to make the charity less dependent on legacies.
The RNLI relies almost entirely on public donations to meet annual operating costs of about £119m.
Legacies raised £73.6m last year, and Popper said the fundraising team would aim to diversify income by promoting direct debit donations, using face-to-face techniques and appealing for corporate donations.
At the turn of the century, the Charity Commission criticised the RNLI for hoarding its reserves. Since then, however, the amount of money the charity holds back has fallen from £200m to £96m, largely because of the falling stock market.
The charity has also had to deal with the added expense incurred by taking its service into inland waterways as well as the seas. The increased popularity of water sports and higher training costs have also contributed.
Referring to the popularity of water sports, Popper said the RNLI would target younger supporters.
"Given that the climate has changed, the key thing moving the strategy forward is that our obligations have changed," he said.
"Although the organisation has been financially secure in the past, there is now a lot more competition in the charity sector. We are a long-standing and well-respected charity, but we need to ensure we are one of the organisations people will consider in the future."
- A significant drop in the RNLI's reserves has led to a fundraising drive costing an estimated £9m
- The fall in reserves has been caused by the stock market slump and rising cost of rescues
- The fundraising and marketing strategy aims to diversify income away from the charity's current reliance on legacies, which last year raised £73.6m.