Mortissian Defence Inc. presents you the finest cannon you can get your hands on. The Mortissian Heavy Hellflare-Cannon, is a machine-cannon, meaning it fires tnt at very high rates. It's got a 3 turn redstone feed, which allows it to fire at it's such high speeds. The best part is, it's got 4 firemode settings. 0 - Fast, 1 - Medium, 2 - Slow, 3 - Semi-auto Burst. It's all self contained, and works by the magic of command blocks (so make sure commands/cheats are enabled so you can turn the output off [/gamerule commandBlockOutput false]). We at Mortissian Defence Inc. promise that it will greatly help you destroy your enemies with ease. Unfortunately it cannot be aimed (and rotating it via mcedit requires you to change the command to compensate for the changed data values) independently from a ship, but turning the ship itself should solve the aiming problem. We also guarantee that it will fire further than any arrow, so no more trying to hit those tnt catches with flaming arrows. Enjoy!

Warranty void if any other redstone component other than the firemode changer is edited.
Warranty: Until an update breaks it or trained operator is killed.