The Royal National Lifeboat Institution has today launched what it believes to be the first UK charity app that works with Apple’s smartwatch, for people involved in its mass-participation fundraising challenge, H2Only.

RNLI is encouraging people to give up all drinks apart from water between 2 June and 12 June. It has asked participants to collect sponsorship and donate the money they save by giving up caffeinated, alcoholic and fizzy drinks.

The app is free to download and will also be available on iPhones and on Android devices. It will set participants daily challenges and allow them to unlock badges. It will also track sponsorship and let users share photos and join teams.

Ailsa Mackenzie, digital projects manager at RNLI, said: “We are really excited to be the first charity based in the UK to have an app for the new Apple Watch. This app is designed to keep H2Only participants engaged during the 10 day challenge. It will guide them through the choppy waters when temptation kicks in, and it will help them to raise as much money as possible for our lifesaving charity.”

It was built by Bournemouth-based digital agency 3 Sided Cube.

Steffan Ciccotti, RNLI volunteer crew member at Tower lifeboat station in London, who is taking on the H2Only challenge, said: “The H2Only challenge is extremely tough. We know that going 10 days without a morning cuppa, a pint after work or a can of fizzy drink will be really hard for everyone taking part.

“I can’t say that I’m looking forward to the challenge. But every pound raised is so important to the RNLI. As a charity, we rely on the support and generosity of the public so that we can continue to save lives at sea.”

Peope can sign-up for the H2Only on its website.