The life-saving charity “stood down” Tom Clark for leading what it called an “unauthorised training exercise”.
Mr Clark, who was awarded an MBE by the Queen in 2016 for his service to Scarborough RNLI, called the claims “rubbish” and said the charity had “lost focus of saving lives at sea”.
A wave of support online for Mr Clark has begun, with one Scarborough business saying it would remove all pictures of the RNLI in a show of solidarity.
The issue revolves around a training exercise last year.
An RNLI spokesperson said: “An internal RNLI investigation has recently been concluded into an incident at Scarborough lifeboat station and, as a result, the volunteer coxswain involved has been permanently stood down.
"Both the inshore and all-weather lifeboats at Scarborough remain on service.
The volunteer crew continue to work closely with the RNLI and the lifesaving operation has not been impacted by this decision.
“The RNLI was made aware of an unauthorised all weather lifeboat training exercise led by the coxswain. It is not acceptable to take out the lifeboat under these circumstances, without proper permissions, and subsequent evidence during the investigation contributed to the decision to stand him down.
“As an emergency service, the RNLI expects its crew members to behave professionally – not just in terms of maritime expertise, but also in behaviour and respect for others - and to carry out their role with due care and diligence at all times.”
A peition has now been set up to get him reinstated.