Destructive flames could be seen from streets away as Valentine's night turned to disaster for four boat owners.
A mystery blast has rocked a Perth harbour, destroying boats and forcing a popular restaurant to be evacuated.
Firefighters spent hours battling the blaze overnight at Hillarys Boat Harbour but four vessels were destroyed.
Toxic smoke billowed over the harbour, in the city's north-east, about 10.30pm.
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Skippers stopped in their tracks desperately trying to help.
Andrew Beale was among many who called Triple Zero.
"It was amazing how quick it happened, that was the scariest factor," he said.
"But fortunately for everyone there was no one on board, everyone was safe."
Flames were spotted from streets away as The Breakwater was evacuated and a HAZMAT alert issued.
"Unfortunately for us the cause is undetermined due to the fact that by the time fire investigation arrived, all four boats were underwater," Department of Fire and Emergency Services district officer Scott Bulloch said.
Piers melted and the berths were left empty.
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It's the second boat fire at Hillarys in five months.
"Smoke damage – nothing is melted, which is good but we dodged a bullet, that's for sure," boat owner Wayne Adams said.
It's understood one of the owners sold his boat after 14 years just days earlier.
They were forced to break the news to the new owner when they came to complete the handover this morning.
Now there's a major recovery mission to resurface the vessels.
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