Further digging has unearthed the story of a Dutch ship-borne IED on about April 6th, 1588, a few months before the Armada. I’ve found reference in letters to Elizabeth’s spy-master, Francis Walsingham, from an agent, David Cabreth,based in Calais and which enclosed a letter from Cabreth’s “servant” Renault le Normand, based I think in Dunkirk. Cabreth was an adventurer from King’s Lynn in Norfolk who had a privateer’s commission (“a Letter of Reprisal”) against the Spanish in Northern France, and the typical sort of person that Walsingham used in his network. In this case Cabreth apears to have been running a spy network for Walsingham. In March or April (the dates are a little confused) a Dutch “bark” (a small trading vessel) entered the port of Dunkirk, then held by the Spanish. They were challenged as to the cargo by port security officials and claimed it contained “cheese and beer”. It appears they tied up the ship in the port and then the crew departed in a small boat giving the excuse they had to recover an anchor from near the port entrance. The ship however was loaded with “powder and stones” and by some means set to explode shortly after the crew departed.
Three ships along with the bark were destroyed, two of them carrying Spanish munitions. An area of buildings around the port were damaged. The report suggests the “sudden blast did so terrify the Spaniards that they went howling about the street, crying like cats”.
Fragments of an explosive barrel reported landed on another vessel, which brought it to Calais for investigation – early IED Technical intelligence!
The significance of the explosion I think might have reinforced the Armada’s concerns about explosive ships amongst the fireships launched against it a few months later which caused such disruption and led to the defeat of the Armada by the English in August of that year.
I can’t help wondering if Frederigo Giambelli, the builder of the “Hoop” ship IED in 1584 had a hand in this attack. He had been working for Walsingham since 1585. This device in Dunkirk clearly had to have had a reliable and discreet time fuze – the port authorities might have seen the smoke from a burning fuse.