The Parts of a Speargun

Coated spring steel shafts have been around a long time. It’s been the European shaft of choice for decades and perhaps the most common shaft globally. It’s very inexpensive, has a Rockwell hardness of 50 – 52 (very stiff), and comes in 6.6mm, 7mm, 7.5mm, 8mm, and larger. On smaller Euro style guns 90 cm and less, it flexes less, holds an edge longer, and bends less than a stainless shaft. For open-track guns this is a definite plus. A galvanized coating inhibits corrosion. It will rust wherever the coating is scratched or abraded off. This is normally the tip area. Coated spring steel shafts can last a long time with proper care. After diving, remove the shaft, rinse with fresh water, dry, and then apply a light coat of oil. Well-maintained, they can last many years. Spring steel and stainless are increasing in price every year. I consider spring steel shafts to be disposable. Inexpensive, they can eventually be discarded or become a back-up shaft.

Maintenance is minimal with stainless steel shafts. Good stainless shafts are usually made from 17-4 stainless steel and heat-treated to H-900. Rockwell hardness is 38 – 41. Less stiff than a spring steel shaft, it can be bent more easily. A higher Rockwell hardness would make the shaft more brittle. Stainless steel 17-4 H900 is the industry standard, used by most companies providing stainless shafts with their guns. It is an alloy of chromium and copper, used where high strength and moderate corrosion resistance is needed. The price of a stainless shaft can be high – upwards of 25% more than a spring steel shaft.

I use both shaft types depending on the situation. I use spring steel shafts for economy. They bend less, dull less, and perform better (less flex). I just spend a little more time to care for them. There are some custom stainless shafts that are sold for 100+ USD per shaft vs 50 USD for a spring shaft. For blue water, I use stainless shafts because sometimes proper care is not possible. Stainless shafts require lower maintenance. Most blue water guns will not be shooting fish as often as a smaller reef gun and a stainless shaft works just fine.

Spring steel shafts have many size options. Most fish can be landed with a 7mm (9/32in) or 7.5mm. The 7.5mm shaft is a perfect blend of size and stiffness. It performs better than a 5/16 stainless shaft. It is lighter, stiffer, and needs less band power. This means better distance and straighter trajectory with less flex and bending. For shooting fish like groupers, this is a good choice. Many commercial spearfishers use 7.5mm to harvest groupers.

For lower maintenance use stainless. For lower cost, higher stiffness, fewer bends, and less dulling, go with spring steel.

Also, see the video (above). Gun handles can be rear, rear plus, or mid (as in mid-handle).

1. REAR – These are traditional spearguns with handles at the rear like a Euro-styled gun. Loading is easy from the hip or chest. It is used by entry-level to advanced divers. It is the easiest to aim. The disadvantage is that once you get past a certain length, maneuverability can be an issue. Many scuba divers prefer the easy hip loading of rear-handled guns.

2. REAR PLUS – The rear plus gun is chest-loaded and provides more power and distance because the mechanism has been moved back. Aiming is easy.

3. MID – Mid-handled spearguns are designed for maneuverability with a pivot point closer to the center of the gun. This is a great advantage when tracking game and maneuvering in and around obstacles. The rear mechanism placement maximizes band pull length and allows for a longer shaft. This means more power and distance. Usually chest-loaded, this gun is popular with advanced divers who need maneuverability and power.

UHMWPE is often incorrectly called HMPE or High Modulus Polyethylene. The higher the molecular weight, the stronger the fiber. There are many types of UHMWPE. The best known are Honeywell “Spectra” and DSM “Dyneema”. Not all Spectra fibers are the same, nor are all Dyneema fibers the same. Fiber diameter is called denier. Fibers of the same denier can vary in strength by up to 40%. In some cases, there are up to 3 grades per denier. There are 4 classes of Spectra fibers (USA) with varying grades, and there are 7 classes of Dyneema fibers (Europe). The main difference between Spectra and Dyneema fibers is the number of filaments per denier. Dyneema has more fibers per denier, giving it a softer hand as filaments slide when bending. Spectra has fewer fibers per denier, making it harder to break the thicker individual fibers and making it less likely to “Fuzz Up”. If a line is not Spectra or Dyneema, then it is called generic UHMWPE, or incorrectly, HMPE, and comes from China in one low grade.

Variability in the diameter of individual filaments causes the fiber to vary in strength for a given denier. These fibers are typically used where variability in breaking strength and abrasion resistance are unimportant. Spectra is the most expensive. Chinese UHMWPE is up to 3 or 4 times cheaper. Similar appearance does not mean similar performance.

Fiber construction affects performance. Complex constructions and tighter braids require sophisticated braiders and knowledge of how fibers work together. They take longer to produce and are more expensive. Tighter braiding requires more fiber and results in higher abrasion resistance. Fiber linearity results in higher strength. Engineering a line for a specific application (other than very light lines under say 200 lbs) involves a combination of fiber linearity for strength, and a tight over-braid for abrasion and tangle resistance.

The third component of well-engineered lines is coating or impregnation, which minimizes salt water penetration and maximizes abrasion resistance. Polyurethane is typical and comes in different performance formulations. Q-PowerLine has an exclusive proprietary formulation for salt water.

Float lines are standard for most blue water diving. You can bag larger fish without losing your speargun and fish are easier to control. However, it can get tangled on rocks or hung up in thick kelp.

With reels, there is no line hindrance when navigating caves, ledges, currents, and kelp. They hold from 50-100 meters of line. However, thinner line typical of reels makes it harder to control fish, and if used in blue water you could lose your gun to a big fish.

Consider your diving conditions. Is there kelp? How big is the quarry? Is there enough line?

Bigger guns have longer range. The correct size depends on visibility and game. In visibility of 2 to 5 feet, a “pistol” would be best. In 5 to 10 feet, a 35 to 42 inch gun is great. For visibility greater than 10 feet, 50 to 60 inches is recommended. For fish under 10 pounds a 50 inch or smaller gun will do. For longer shots on bigger fish, 55 – 63 inches may be needed. Blue water diving requires guns at least 60 – 68 inches. The number of bands varies from 3 to 5. Be conservative and know the effective killing range of your speargun. We should be good sportsmen and use the right tool for the job

I have worked with all different woods, but now I use only teak. Why? Because it is the most stable to work with, it is fairly easy to acquire, and I rarely have problems with warping or delamination.

Here is what I have found while working with four commonly used woods. All are very nice to work with and have advantages and disadvantages.

Oak: It is hard, dense, and has nice grain. It does not rout easily and tends to splinter in sharp pieces so eye protection is a must. Of course, that should be standard for anyone working with power tools. Oak tends to warp very easily, even when laminated. It will absorb moisture through any break in the stock – screw holes, scratches, etc. A strong seal and good finish is critical. It tends to get dark wood rot stains wherever moisture can seep in. A very well-known company used to have oak and teak laminated guns. They are no longer available. Because of warpage and different expansion rates the stocks would delaminate over time. It happened to me too.

Mahogany: It is soft, easy to work with, and porous. If moisture gets to the stock it turns dark. It is very buoyant. I used to make ballast wings (yes me too before I saw the light) out of mahogany. It is very important to get a good seal. Many manufacturers like this wood because it is readily available, easy to work with, and cheap. Almost half the price of teak.

Purple heart: I fell in love with the look of this dense purple wood the first time I saw it. The down side is that it is very brittle, tends to splinter, and warps easily. I love the look but hate the splinters. It will turn a lovely tan or brown color over time as UV fades the wood.

Padauk: Very dense and tight grained, it splinters unless sharp blades are used. It is not very buoyant. A few guns sank on me. The big downside is the large amount of sawdust generated. You need to be very careful when sanding and working with this wood. This wood will also turn color with time.

Do not mix woods. Some make beautiful mixed-wood guns. But a laminated stock of a single wood is less likely to warp or delaminate. Many years ago, I decided to make the most beautiful gun and used all of the aforementioned wood in a laminated stock. I was so proud on the inaugural dive. But not only did it start to delaminate – it had warped after only a day. It had four coats of epoxy and was finished as best as I could do at that time. It was just that the different woods expanded differently – more than the epoxy could handle.

Make two guns. Use a cheap piece of wood to test cuts and routs before working on the real stock.

There is always a chance of delaminating or warping. Stick with one wood and try to use a very dense stable wood like teak. There really isn’t a substitute for teak. If you prefer to mix woods seal everything well.

Do not cut corners. Make your gun as safe as possible. The only safe speargun is an unloaded speargun.