These people have successfully fended off the pirates for quite a long time, losing no more than a few of their own number at every encounter. However, in the last ten years or so, the pirates have started to attack with fearsome weapons, and the flyers' technology can't match the pirates'. The elders of the flyer race have sent a number of envoys to the mainland to learn more about these weapons, to bring samples home, and to establish relationships that will allow their manufacture on the island.
Long story short, the development of firearms on the mainland is growing apace, and the envoys are learning as much as they can and trying their hand at developing specific defenses against ships bearing cannon and musketeers (well, not the French kind).
Our heroine has designed a rudimentary gravity bomb; a simple iron casing filled with gunpowder that's meant to explode when dropped from a sufficient height. She envisions her fellow flyers dropping these bombs on attacking ships to injure and kill the crew without outright destroying the ships (there's bound to be something useful on them after all). Assume the ships are of the variety you might see in Master and Commander -- lots of sail and rigging, cannon and muskets and flintlock pistols.
If you have a mind to, review the description below. Would such a device function as intended? Would it be sufficiently lethal to turn the tide of a coastal pirate raid? If a device like this would explode as intended, what sort of injury radius are we looking at? Any other feedback would be lovely.
The Mark I Gravity Bomb is an iron egg attached to a guiding rod. The entire apparatus is about the length of an adult human male's forearm and weighs three pounds. The iron egg is segmented to allow for easy fragmentation when it explodes, and resembles a small pineapple. The guiding rod resembles an oversized arrow shaft, complete with thick wooden stabilizer fins as "fletching." The iron egg is filled with about a pound and a half of gunpowder. The conical terminator (usually made of thin brass or some other easily compressible material) separates from the bomb to reveal a percusson cap that seats over a small aperture in the egg. Inside the terminator is a firing pin poised over the percussion cap. A sufficient impact will crush the terminator, driving the firing pin into the percussion cap and igniting it. This ignition sets off the gunpowder within the egg, detonating it and sending fragments of the egg flying.