From Drebbels wiki
Drebbel used his knowledge of chemistry to produce explosives.
From other documents of the date of March, 1630, it appears that Drebbel and Abraham Kuffler had been employed in the late expedition to Rochelle, by authority of an Order of the Council, issued on July 1 3, 1628, for the preparation of three extraordinary fireships, under the direction of Colonel Peblis, and six engines for fireworks, according to the directions of the Lord Admiral, with allowance of pay to the chief officers of the same fireships and engines ; among whom are Abraham Kuffler, 20 Shillings per diem, and Cornelius Drebbel, £150 per month. Kuffler and Drebbel petitioned for further payment, but this was refused.
Wednesday, 11th November 1663
11th. Up and to my office all the morning, and at noon to the Coffee-house, where with Dr. Allen some good discourse about physique and chymistry. And among other things, I telling him what Dribble the German Doctor do offer of an instrument to sink ships; he tells me that which is more strange, that something made of gold, which they call in chymistry Aurum fulminans, a grain, I think he said, of it put into a silver spoon and fired, will give a blow like a musquett, and strike a hole through the spoon downward, without the least force upward; and this he can make a cheaper experiment of, he says, with iron prepared. (Samuel Pepys)