Man: So here's the smallest, cheapest, easiest, fastest version of a portable canon that I could keep working. Takes up 30 seconds to build and fire. This is the southward-facing version. The northward-facing version is a little bit harder but I'll show you how to make that too. All right.
So let's look at how to build this guy really quick. I need a diamond shovel, TNT, a trigger like a lever or a pressure plate, some redstone, and a water bucket. Dig trench three-long, drop the water, TNT. You can pick up those dirt blocks, put them right there. Redstone, and then drop one trigger here, one trigger there. TNT goes there. Light the charge, light the TNT, there you go. Count should be about four Mississippi between lighting the charge and the shot. You'll figure out the time yourself. You can see that came up a little bit short. If yours' coming up short, you can always just head to another row.
Okay. So before we look at other directions, let's look at why this works so well when facing south. When you light a TNT with redstone, it's going to jump a little bit north, some random direction north. So when we light a canon, this TNT's going to jump and the shot is going to jump on top of it. So it ends up being at the perfect angle even if it's just a tiny charge.
Now on the other hand, we have the north-facing canon. This one as you can see takes a little bit actual work but basically it's the same. You need something for the TNT to sit on, and you need something here to place the TNT on. So now that it's placed, this lever is going to both light the TNT and initiate that trap door. So I light the charges same as always, and the shot, and we still get great results. These blocks on top prevent the TNT from jumping too high and then going out of the channel or landing on top of the shot.
So here I've got a canon facing east, same design, same trap door, same levers. Light the charge, and light the shot. Perfect. Oh man, we almost got that cow. Now one key thing is, when you're facing east or west, always make sure that these, let's call them guide blocks, are always on the north. If they're not on the north, it's going to jump out and it's going to be very bad. I will demonstrate that right now. Now note everything is the same except for the position of the guide blocks. Light it and the TNT jumps out, and now it's not on the water anymore. Still got a great shot but our canon is done. So always make sure you know which way is north.