This article from theĀ Portsmouth Telegraph, or Naval and Military Journal, february 1801,describes Mr Fulton experimenting at Havre and at Brest, with his Fish-boat. In the course of his experiments he remained under the water for several hours, and could set lite to objects without been seen. It was reported that he, also invented arrows or darts, which he can fix in any vessel that he intended to set on fire. (source:
Portsmouth Telegraph, or Naval and Military Journal 1801 Vol 1, please note that the image shown is of lower resolution and quality than the image on the CD-ROM)