Spearfishing is something that I’ve wanted to do for years, and living on a small subtropical island surrounded by beautiful ocean means that there’s really no excuse to not do it. So, since quitting my job, that’s one of the things that has occupied my time and energy. Considering the fact that spearfishing is one of the most physically taxing sports, and that spearfishing with a gun is banned in Okinawa, I’ve been having a rewarding, if somewhat exhausting time fishing with a Hawaiian Sling.
The Hawaiian sling is basically an underwater slingshot with a tube to aim (not guide) the spear. The one pictured here is made from a bamboo tube and was initially meant to serve as a substitute for the sling fashioned from wood. That one has a smaller hole for the spear, which I thought was necessary for accurate aim. But according to some sources, the larger hole is fine because you aim down the shaft, not with the handle of the sling. This assertion is backed by my experience using the sling in the picture, as I have continued to get fish. I do plan to make more slings with small holes, however.
The little “cup” on the rubber tubing was fashioned from bamboo. The little aluminum cups you can buy cost $6 apiece if ordered online, which is pretty steep when you figure in shipping. The necessity to be frugal (or cheap) meant that I had to invent the bamboo cup. It seems like an obvious solution when you see it, but I had considered several more difficult and less aesthetically pleasing ways to fashion a cup before trying this one. The bamboo is the easiest way- you simply find bamboo that’s the right diameter to hold the end of the spear, and cut out a “knuckle” containing a node. That way, you can drill the hole for the tubing to one side of the node and have the spear cup on the other. The node acts as a natural barrier.
Drilling small, round objects can be difficult. I kind of cheated here, first drilling a very small (around 1mm) hole with a Dremel. Then I used a small round grinding bit to enlarge the hole. I imagine it would be difficult to drill an accurate and clean hole freehand, especially without a clamping setup for the bamboo. If you do try this, it would be easier to drill before cutting out the section of bamboo. That way, you have more to hold on to when drilling.
I didn’t find any concrete guidelines for how long to keep the tubing. This is because tubing varies, a lot, and strength also determines how long or short you should tie the tubing. The way I did it was to simply grip both ends of a piece of tubing and pull back to test the tension. This gives you a good idea of the length of tubing that will be comfortable for you. Remember that it should probably feel a bit challenging to pull back on the sling. You want a balance between ease of use and power. If pulling back on the sling leaves you exhausted, you probably won’t get many fish. The same goes for if the tubing is too loose- your shots will be weak and you also probably won’t get any fish.
As per a discussion on one spearfishing forum thread, I used a whipping knot to tie the sling. It’s really easy to do, and hard to forget. I read that you want the length of the tie to equal 1.5x to 2x the diameter of the sling shaft .
I highly recommend making an underwater target to practice with. A target consisting of a neoprene fish with a length of cord tied to a weight is probably the simplest, least bulky way to do it. If feels bad to wound a fish and have it get away, for yourself as well as the fish! I was somehow able to get close enough to a parrotfish which must have been at least a foot and a half long, and I hit it with my spear. But it shook loose. I wonder if it’s dead or doing okay. The scene has played over and over in my mind. It seems like such a waste. But the only thing you can really do is become a better shot, so let the neoprene fish play its part in helping you secure real fish. It’s the responsible thing to do 
Finally, become adept at sharpening your spear. Missing your mark and hitting rocks, sand, etc. rapidly dulls the point. A dull point is less likely to adequately penetrate a fish．
Dull from yesterday
I tried grinding using a Dremel and grinding tip. It was slow, coarse, and noisy. A simple metal file works a lot better. I ground a rather crude tri-tip, which seems to be a very good tip. It’s easier to make the main tri-tip surfaces, and then file the very tip to be sharp (this is much better explained in “The Razor Edge Book of Sharpening”, but perhaps I’ll do a future post on this point, no pun intended). Sharpening will generally only takes a few minutes between sessions.
Several sessions on and still a beginner, I am getting a sense that spearfishing has the potential to keep one fed. Happy fishing!
Most recent catch:
Smaller fish mean less mercury ingested?
