The first explosion killed several hundred people in the city of Santander as well as on the ship, and was Spain's worst peacetime disaster in the 19th century.

The second explosion killed a number of workers who were salving the remainder of her cargo from her sunken wreck.

[3] Benisaf's engine room, stokehold, bridge and single funnel were amidships, between her number two and three holds.

She had a single screw, driven by a two-cylinder compound steam engine built by R and W Hawthorn of Newcastle upon Tyne.

But soon after joining Ybarra's fleet, on 4 September 1886, Cabo Mayor ran onto rocks on her namesake and became a total loss.

Therefore Cabo Machichaco was required to spend ten days at anchor in quarantine before entering Santander.

On the morning of 3 November she entered port, and about 0700 hrs she docked at Pier 1, which was a timber jetty in the centre of the city's waterfront that extended about 160 ft (50 m) from the shore.

Cabo Machichaco's Captain, Facundo Léniz, decided to flood the holds, sinking the forepart of the ship, to extinguish the fire.

About 1600 hrs her Master, Captain Francisco Jaureguizar y Cagigal, with one of his officers and about 40 of his crew came alongside Cabo Machichaco in a steam launch to help.

[4] In order to sink the ship quickly enough, the plan was to use sledgehammers and cold chisels to open a hole in the port side of her hull.

[7] At about 1645 hrs, only minutes after men started work with the sledgehammers, the dynamite in her number two hold exploded.

The initial force of the explosion was upward, killing everyone on the forward part of the ship, including all the officers and men who had come from Alfonso XIII, but not the half of the crew who were salvaging items aft of the superstructure.

[11] But the divers became so distressed at the large number of the dead in the water, and the extent of their injuries, that they successfully pleaded to be released from the task.

[7] The first explosion left about 11 tonnes of dynamite in Cabo Machichaco's number three hold, unexploded, but under water and leaking nitroglycerin.

On 15 March 1894, four months after the first explosion, a "technical board" of navy, army and civil experts arrived in Santander to try to solve the problem.

The next day the board decided that the cargo, including the dynamite, should be salved, with salvage divers working at night.

After the Guardia drove them away from the company office, some of the crowd went to the harbour, where they cut the hawsers on an Ybarra ship that was moored there.

[14] On 30 March 1894 the Spanish Navy gunboat Condor used explosive charges to disperse the remains of Cabo Machichaco's wreck.

It is a thick stone cross designed by Santander's then municipal architect, Valentín Casalís, with the dates of the two explosions on either side.