it may be once in a lifetime but when it happens, it's nice not to sink. Ten years ago a Radar wire inside the mast shorted to ground on Brendon. It wasn't a maintenance problem and my Boat US insurance covered the ten thousand dollar yard bill. When the wire went to ground it set up a 7 amp current draw but the fuse or the Radar was a ten amp. It set and cooked for three days and took out all of my hull fitting, the shaft and the prop. The only thing keeping the thou hull fittings and hoses connected to the boat was the 5200 sealant. Everything else was gone. Make that GONE. The incident was written up in the Boat US magazine so you can look it up if you wish in the back issues. 5200 will rip the decks right off a fiberglass boat but there are ways to get around ripping things off with brute force. having said all that, I mostly use 4200 UV protected on projects that require a strong bond and seal.