Whilst responding to an incident at Selsey Bill on Sunday (September 13), in which six adults and children were cut off by the tide, the RNLI lifeboat crew found the station had been vandalised.
Sharing the news on social media, the lifeboat station said one of its windows had been smashed alongside the footpath that runs down between the station and public toilets.
Coxswain Rob Archibald said: "It has happened since the station was locked up on Friday evening.
"It was discovered whilst the inshore lifeboat was out saving a life and rescuing six others. What can you do?
"If people want to smash a window, they will. It's very demoralising."
The vandalism comes as another blow to the lifeboat's finances, which has suffered from a lack of fundraising during the coronavirus pandemic.
"Unfortunately, we are going to have to spend out on a new window," Rob said.
"Everyone is gutted because we have all spent a lot of time making the place look nice. It's a shame."
If you have any information, please contact the boathouse on 01243 602833.
Sussex Police has been approached for comment.
A message from the Editor, Gary Shipton:
In order for us to continue to provide high quality and trusted local news, I am asking you to please purchase a copy of our newspapers.
With the coronavirus lockdown having a major impact on many of our local valued advertisers - and consequently the advertising that we receive - we are more reliant than ever on you helping us to provide you with news and information by buying a copy of our newspapers.
Our journalists are highly trained and our content is independently regulated by IPSO to some of the most rigorous standards in the world. But being your eyes and ears comes at a price. So we need your support more than ever to buy our newspapers during this crisis.
Stay safe, and best wishes.