A new app set to be launched on Tuesday, 26th May, by the Royal National Lifeboat Institution (RNLI) will be the first UK charity app to work with the Apple Watch.

Designed to support the charity's H2Only fundraising challenge, it will be available to download for free from the Apple App Store and Google Play for Android phones from Tuesday, 26th May.

The purpose of the H2Only app is to help the thousands of people set to give up all drinks except water for ten days from 2nd June, raising vital funds for the lifesaving charity.

Designed to keep participants engaged during the tough ten day challenge, the H2Only app will set daily challenges to be completed. It will also allow badges to be unlocked, track sponsorship totals, and let users share photos and join teams.

The Apple Watch app provides notifications for new challenges, with the glance showing details of each daily challenge. It will also allow users to see a countdown to the beginning of the challenge, and then view their completed challenges on the Apple Watch as the H2Only challenge progresses.

Ailsa Mackenzie, RNLI Digital Project Manager, said: "The RNLI has a proud history of innovation – from our methods of fundraising over the years, to the pioneering designs of our lifeboats.

"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 ten 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.’

Bournemouth-based digital agency 3 SIDED CUBE developed the H2Only app for the lifesaving charity. iOS Developer, Sam Houghton, said: "The RNLI has always been a very innovative charity, so to have worked with them on the first UK charity Apple Watch app is an incredible privilege.

"We knew we wanted to build a multi-function app that would engage users and keep them motivated. The H2Only app tracks donations and sponsorship totals, lets users complete challenges, share photos and even join teams.

"An Apple Watch app suits this campaign perfectly, elevating an already personal user experience and being an ideal use of the unique functions of the watch".

Steffan Ciccotti, RNLI volunteer crew member at Tower lifeboat station in London, is taking on the H2Only challenge. He said: "The H2Only challenge is extremely tough. We know that going ten 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".

Anyone brave enough to take on the H2Only challenge can sign up at H2Only.org.uk before the challenge runs from 5.00pm on Tuesday, 2nd June to 5.00pm on Friday, 12th June.