How do you mount the knife to the sappling?
Thew knife comes with a small notch on the rear handle edge you can use to clamp the knife to the spear with a screw. That is not secure enough for me. What I do is drill two small holes in the handle and use 2 short dry wall screws to fasten it up tight with the phillips head on my swiss army knife. Some people go through the trouble of making the whole spear before the trip and use cross bolts. I like to do it on the way.
My father and uncles all are camp whittlers. I am the same. The first day out I keep my eyes peeled for a good sappling that is straight and a little wider than the hollow handle on the top end, then harvest it with an axe. Hardwood is best(maple) but a good long straight black spruce sappling from a thicket where they grow tall and straight will do just as well if you dont mind peeling the bark off, or the sticky sap.It should be about 8 feet long. In camp the first night I simply whittle the sappling end into the right cone shape, by repeatedly fitting it into the handle, until I get a solid snug fit way up into the handle. I then take out my trusty swiss army knife, open up the phillips head screw driver and screw the short dry wall screws into the holes I have predrilled. ( Drilling the holes about 2 inches apart takes about five minutes with a hand drill at home.)When I finish the fitting and squaring the butt, the spear is usually between 6 or 7 feet long. Make sure to mount the knife on the skyward end of the sappling, its incredibly bad luck to mount it on the earthward end, but do as you please. If the butt starts to split you can resquare it or serve it with tightly wrapped and tied fish line. As time goes on, you will get better at selecting straighter sapplings and smoothing the shaft. Sometimes I use beach sand to get the shaft really smooth, and by the end of the trip, the spear shaft is scrimshawed with art.I even tie feathers I find to the haft just behind the knife handle, using fishing line.Raven feathers work well to keep track of wind direction.
I keep the spear on the floor of the canoe with the knife in the sheath, and use it for poling the canoe when in shallow water. I leave the sheath on when poling.My dad taught me how to stand up and do this but be careful, its tricky balancing with two in the canoe if your partner moves much. The Indian people used to do this a lot. (If going into rough water, I lash the spear to the thwart with rope, just like the other gear.) I usually whittle the spear shaft , as an ongoing project in camp, peeling the bark off, smoothing out the knots and squaring the butt. Its good that the butt has a few knots in it to discourage splitting, you can see that when you cut the sappling. I do this smoothing work as a matter of respect for the weapon, and if a native Indian sees it, he will understand why you have it a lot better, its not just a cold killing tool but a way to pass the time enjoyably.
At the end of the trip, I take out my trusty swiss army knife, and unscew the dry wall screws, and put the knife in sheath in my pack. Usually I burn the spear at my last camp fire. (I have even used the spear as a quick in a pinch fishing rod by tying leader and hook to it).
I do get some queer looks from other canoists about the spear, but have never been castigated, when I tell them its bear insurance, because of the recent attacks you have mentioned. If you ever have to use it, prod the bear with the spear about its cheeks and nose until it stands up and sink the spear right into its solar plexis or base of the neck as deeply as you can, avoid the ribs. If you have to thrust into ribs do it from low to high at an angle so the blade will slip in between them.Pull it out and reinsert as many times as necessary.You will find after the first few prods that most bears will turn and tucker, rather than stand.If the spear shaft is broken by the bear after you have inserted it, go for your camp axe and finish the job. BTW Do not try to use it on a moose that might chase you. Thats what trees are for ( LOL), but I am told that Indian people use to wait for moose to feed on Water Lilly roots, and stalk the moose by paddling up on it silently when its head is under water. When next to the animal they speared it deeply towards the heart from the left side if possible, just behind the foreleg shoulder. They must have been wild crazy and hungry! I have done the same, but used a camera, instead of a spear.
A spear is a good weapon, and not at all a toy. My dad always said to be real careful with it.
There is a photo here of the result of spearing a bear.
http://www.apgs.com/spear%20hunt.jpg
Good luck!