Choosing the Appropriate Speargun by Ray Klefstad
A spearo looking to aquire a band-powered speargun is faced with a big decision: which model is best for his or her favorite type of hunting. A speargun can be a major investment, so it is worth doing some research before making a decision. The most common specific questions are these: 1) What speargun is best for reef hunting? 2) What speargun is best for a combination of reef hunting with some blue water hunting? and 3) What gun is best for hunting big game like tuna? You can use the following information to help you answer questions such as these and I give my recommendations at the end of the article.
This decision is similar to choosing the right firearm for hunting on land. For example, if you are hunting elephant, you could use a .22-caliber rifle, but the elephant will probably be merely injured and will escape, only to suffer and possibly die later, out of your grasp. However, if you are hunting rabbit, the .22-caliber rifle is ideal: it will do the job, the ammo is cheap, and such a small-caliber rifle has little or no recoil. Likewise, choosing the right speargun for your hunting situation will give you the better results and increase your enjoyment of the sport.
We hunters have a responsibility to ensure that we land most of the fish we decide to spear. It's impossible to guarantee we won't lose fish on occasion, but we should try to lose no more than five or ten percent of the fish we spear. Using inadequate gear is one of the main reasons for losing fish (and gear). A more powerful speargun, better shooting line rigging, use of slip tips, and use of floats with bungies can all help reduce the number of lost fish. Twice I've heard of divers losing very large white seabass because they were hunting in the kelp and using a floatline without a large float (they were trying to make it easier to maneuver through the kelp). A monster fish swam by, and the diver speared it, only to have the fish swim away, along with all of his gear, never to be seen again. These fish probably perished, and the divers lost some very expensive equipment.
A poor shot is another reason for many lost fish. If a strong fish is shot in the belly or if the spear didn't penetrate far enough through the fish, that fish may tear off, only to die. A powerful, accurate speargun can help reduce this type of loss. Use of slip-tips also helps reduce fish lost due to tear-off.
Ideally, you may want a variety of spearguns to suit different needs for the various types of hunting you do. However, cost often forces us to select one that may suit a variety of different hunting situations. A speargun is a long-term investment, so it is wise to spend some time considering the trade-offs before making a commitment. Here are the main factors to consider:
When the water is clear and the fish are big, you can afford to take longer range shots. When the water is dirty or when the fish are small, you need to get closer, and therefore you may not want such a big cannon.
A longer shaft tends to give longer range. The power bands also affect the range, but the power you can apply to a given shaft is limited, unless you are willing to go with an enclosed-track design. A longer gun is noticeably more difficult to maneuver through the water, while a shorter gun is very easy to maneuver. However, you can get used to diving with a very long speargun.
For a given length shaft and a given amount of power, a smaller diameter shaft (e.g., 9/32") has lower mass and will travel faster (initially) than a shaft with a larger diameter and more mass (e.g., 5/16" or 3/8"). However, shaft energy is lost due to drag in the water proportional to the square (or cube) of the velocity, so a heavier shaft will retain more penetration power at range than the lighter shaft. However, a lighter shaft will have less momentum when hitting a hard surface such as a rocky reef, so tips and shafts will suffer less damage when hunting reef fish.
Amount of power:
Each powerband adds a fixed amount of power to the shaft. The amount of power each band adds is a function of its diameter and its tightness (or the amount of stretch). A typical high-quality powerband made from 9/16"-diameter rubber will give about 80 pounds of force, while a larger 5/8"-diameter band will give about 100 pounds of force. The power is linearly additive, so if you load three 80-pound bands, you will get 240 pounds of force on the shaft. There are other factors to consider (discussed below) as you add more power.
Type of spear tip:
There are two types of shafts in common use today: fixed-flopper shafts and threaded-end shafts. Fixed-flopper shafts have a hold drilled near the shaft end, and a rivet holds one or two floppers directly onto the shaft. There are two alternatives for single flopper placement: a flopper on top of the shaft is called "Tahitian," and a flopper on the bottom of shaft is called "Hawaiian." Users of fixed-flopper shafts often rely on the floppyness of the thinner shafts or on stringing the fish to prevent the fish from tearing its own flesh against the spear, which may result in the loss of a fish. Some very large fish have been landed with these shafts, but the tear-off rate is generally much higher than it is with slip-tips (discussed below). Fixed-flopper shafts are typically more economical up-front, but if you damage the tip, you may have to replace the entire shaft.
If you use a threaded-end shaft, you have a choice of tips: a screw-on fixed-tip or a screw-on slip-tip. The fixed-tip gives little advantage over the fixed flopper shaft, except that you can replace the tip only (and not the entire shaft) after the tip is ruined from too many rock shots. A slip-tip is superior for landing larger fish - particularly those fish with softer flesh, or when you hit the fish in a soft area like the belly or on the edge. A slip tip is a bit more work each time you reload because you must reseat the slip-portion and tuck the cable into the power bands, but it becomes fast and automatic after just a few tries. Slip tips with floppers offer even better holding power.
Rear handle vs. Mid handle:
The speargun handle may be placed at the rear of the speargun or towards the middle of the gun. Mid-handle guns allow for better balance and for more stable shots, because you can brace the gun with two hands if you like, and the rear extension is an excellent lever for stabilizing with your second hand (the one not on the trigger). Rear-handle guns are less expensive to make, because they don't require rear mechanism placement, which requires an extra trigger slide and a pushrod to activate the real trigger at the rear. Some divers actually prefer a rear handle gun so that they can extend the spear tip closer to their prey.
Speargun Recoil and Balasting:
As the you increase both the mass of the shaft and the power to it (via power bands), you increase the momentum coming out of the front of the gun when you pull the trigger. That forward momentum of the shaft causes an equal momentum of the gun rearwards towards the diver. The Mass of the Spear X Forward Velocity of the Spear must equal the Mass of the Gun X the Recoil Velocity of the Gun rearwards.
MS X VS = MG X VG
VG is the recoil of the gun. You can reduce the VG only by increasing MG -- the mass of the gun. You can do this in a variety of ways, but one that works well is to add lead to the speargun. The gun may become too negative unless you have enough bouyancy (via wood or other floatation) to support that mass.
Lighter shafts with little power require little or no ballasting -- probably one of the reasons that thin shafts are so popular. Macho spearos can hold the recoil of a bigger gun with their bodies by always bracing the speargun firmly with both hands extended forward and elbows locked. This position does limit the shots you can take, since you must have your body in position behind the extended gun. I have hurt myself twice by shooting an under-ballasted speargun while in the wrong position. Once I sprained my wrist by shooting a close fish "from the hip." Another time, I gave myself a cut lip (requiring eight stitches) and knocked my teeth loose by shooting a fish single-handed with a bent elbow. Since then, I always ballast my guns. An under-ballasted gun will tend to shoot low because the front of the gun is kicking upward, which in turn forces the rear of the shaft upward, causing the entire shaft to go downward. Many divers mistakenly blame themselves for this error. The problem is with the speargun, not the spearo.
Enclosed track vs. Open track:
There is a limit to how much power you can apply to each shaft before it will begin to lose all accuracy. When you pull the trigger, the shaft actually flexes and starts to oscillate through the water like a snake. This can cause erratic shaft behavior -- impossible to predict -- resulting in misplaced shots. This problem is eliminated in a gun featuring an enclosed track. In an enclosed track, the spear rides in a barrel similar to a rifle barrel, but the top edge is open to allow the power-band fin-tabs to ride through. The enclosed track forces the shaft to stay straight, no matter how much power you apply. Open-track speaguns are much easier to make and are therefore less expensive. As long as you don't over-power the shaft, an open-track gun can provide reasonable accuracy.
Shock cord vs. Reel vs. Float line
Some guns come rigged with a shock cord, but if you plan to shoot anything other than little fish, you're just going to lose your gun unless you rig with either a float-line or a reel. Some just attach a float line directly to their guns, leaving the gun in-line with the spear and float. But this is not ideal, because 1) it allows the fish to use the inertia of the gun to help tear his flesh so that he can rip off, and 2) the gun may be damaged or lost. Ideally, the float line system should break away from the speargun after the fish is shot, allowing the diver to hold onto the speargun, and allowing the fish to pull the float, unencumbered by the mass of the gun.
For really large fish, a bungie float-line attached to a surf-board float will give you the best chance to land your speared fish. This has been proven on many very big fish. Spearos used to use Norprene for bungies, but now Ron Mullins has developed a new formulation for bungie material that is superior for big game like tuna.
A reel is very convenient for diving in kelp because you don't need to deal with float-line tangles. A reel is also more convenient when diving kelp paddies or other floatsome because you jump in and out of the water fequently and you don't have to deal with the float line each time. I also prefer a reel when diving down to the bottom of deeper reefs because you don't get the drag from the floatline. Although some very large fish have been landed with a reel, a float line is more effective and safer for use with larger gamefish like tuna and bill fish.
It is important to get your spear tip all the way through the fish so that the tip can do its best to hold on to your prize. For larger fish, this means you must penetrate through two or even three feet of flesh, possibly hitting some bones along the way. Heavier shafts driven by lots of power are the ideal setup here.
Range is mostly a function of momentum, but for a given amount of power, a shaft with higher mass will tend to retain more of its penetration power at longer range.
You get lots of bang for your buck with the Euro guns like the Esclapez, but they lack what it takes to consistenly land the bigger fish. Divers can convert them to take larger fish by rigging with a break-away with float and a slim slip-tip made by Bill Kitto.
Here are my recommendations of spearguns for several common types of hunting including those mentioned in the introduction. The lengths should be for the entire mid-handle rear-trigger speargun. When using a threaded shaft, it should be about the same length as the gun, so a five inch long slip-tip plus adaptor will extend the overall length of the shaft by about six inches. Add this six inches to the shaft length for the correct Hawaiian or Tahitian shaft.
reef fish (grouper and snapper):
48" by 9/32" or 55" by 5/16" with slip-tip, fixed-tip, or Haiwaiian shaft.
kelp (white seabass, calico bass, barracuda):
48" by 9/32" or 55" by 5/16" with reel - for easier maneuvering through the kelp
structures (like oil rigs) or floatsome (like kelp paddies) (mahi-mahi, amberjack, yellowtail, school-size tuna):
55" or 60" by either 5/16" or 3/8" rigged with reel if getting into and out of a boat frequently or with float line if in the water for longer periods or shooting large gamefish like tuna, wahoo, or billfish.
55", 60", or 65" by either 5/16" or 3/8", with the thicker shaft giving more range
3/8" shafts are the rule for maximum range and penetration 60", 65", or 72" with the 65" being about ideal for range and comfort while diving
multi-purpose (reef with occasional blue water):
48" by 9/32
55" or 60" by 5/16"
60 by 3/8" (my personal favorite)