An operation is under way to use explosive devices to blow apart the deck of the stricken container ship MSC Napoli, off the south Devon coast.
Only the deck plates had been holding the Napoli together, which were targeted with explosives on Tuesday.
Attempts overnight to pull apart the two sections of the stranded cargo vessel with tug boats were unsuccessful.
Wednesday's explosions centred on the longitudinal ribs on the vessel's starboard, but senior coastguard Paul Coley said there was no guarantee it would be successful.
Crowds gathered on vantage points to watch the operation - the latest twist in a saga that began with the deliberate grounding of the storm-damaged vessel in January.
The explosives are being used in the £50m salvage operation in an attempt to separate the ship into two pieces, to make it easier to deal with.
MSC Napoli was refloated last week but the results of a diving survey revealed the ship's hull was severely damaged and it was beached again on Thursday.