Speargun Rigging Part 1: Choosing, Sizing and Tying Bands
It’s the day of the big trip and you're stoked. Months of work commitments, family gatherings and a mile long to-do list have been keeping you off the water, but you’ve finally found an opening and made it happen. You head out with your buddy and jump in at a juicy looking spot. Conditions are perfect. You put your face in the water and there’s fish all around. Excited, you reach for your wishbone to load your gun, pull a band back toward the notch and “SNAP,” that one sound a spearo hates to hear. You look down to make sure you’ve still got a hand. It stings, but it is there… However, your band is torn in half. Looks like someone is gonna be trading guns all day. Fortunately, this situation is easily avoidable. One of the most important things you can learn as a new spearfisher is how to maintain and rig your own gear. At the very least, you should inspect your bands for signs of wear and potential failure before a trip. If something is in need of repair, knowing what to do and how to do it can save you a lot of time and money, not to mention save your trip if you are out on a boat or traveling somewhere and don’t have access to a shop.
Looking for Trouble
Inspect the band(s) for any signs of aging and wear. A quick visual check should be enough to recognize anything obvious like deep cracks, nicks and cuts. Pay special attention to the area around the constrictor knots. Discoloration (such as amber bands turning dark brown) can also be a sign that it is time to change them out. Normal signs of use and light aging are OK for the most part. These can include very shallow lines or cracks forming at stress points in the rubber. Don’t be alarmed if a white residue forms on the surface of your rubbers after they’ve been sitting for a while. This is a natural oxidation process and is not a sign of damage or excessive wear.
You should check the constrictor knots and wishbone as well. Dyneema and spectra wishbones that are excessively worn or frayed should be replaced. Constrictor knots should be tight, and the cut-ends melted into a ball so the knot doesn’t untie.
My personal rule is if anything looks like it might break, replace it. The process is easy enough and the materials are cheap enough that it makes no sense to leave small problems unaddressed until they become big problems on the water.
Band Choice
One of the great advantages of tying your own bands is being able to choose between a variety of different band sizes, materials and configurations. Of course, the easiest thing is to just match what you already had on the gun, but learning a bit about bands will open you up to new possibilities, and perhaps you’ll find a setup you like even better.
When choosing bands, there are a few things you will need to consider: the size, the material and the configuration (number of bands).
Size
Bands are sized by diameter which is typically expressed either in millimeters or fractions of an inch. The common sizes are 14 mm (9/16”), 16 mm (⅝”), 18 mm (7/10”) and 20 mm (¾”). The larger diameter bands (18-20 mm) can store more energy when stretched, so they are typically used for bigger guns, heavier shafts and more powerful setups. Smaller diameter bands are better for smaller guns where less power is needed. There are some exceptions to this generalization though. For example, some divers enjoy a single 18-20 mm band on a hole gun because it is quick and easy to load and provides plenty of power at short range. On the other hand, many blue water hunters have taken to using multiple (4-6 or more) 14 or 16 mm bands rather than one or two 18-20 mm bands because the smaller diameter bands offer a more controlled release of energy, which translates to a smoother shot with less shaft oscillation. This means less recoil and greater accuracy!
Material
The raw material of most high quality speargun bands is latex rubber, but different manufacturing methods can create bands with various properties. Without making things too complex, we will divide band material into two categories: reactive, and progressive bands.
Reactive bands release their loaded energy in a quick, powerful burst. They have become the preferred choice for many divers because they offer a fast, powerful shot, but all that power does come with some slight disadvantages. Because they dump all their energy into the shaft shortly after the trigger is pulled, they can contribute to greater recoil and less range.
Progressive bands release their energy evenly throughout the entire time they remain connected to the spear. For divers wanting a smoother, more controlled shot with less recoil, especially when stacking multiple bands together on longer guns, progressive bands offer a significant advantage.
In general, for shorter guns, short range shots, or situations where a fast, powerful shot is needed, reactive bands will be a good choice. For longer guns with multiple bands and in situations where range and accuracy are important, progressive bands may be preferable.
Quality is important!
Keep in mind that not all rubbers are created the same. Many top spearos test a sample of rubber before buying more to make sure it is of good quality. At the very least, it is important to source your rubber from a reliable manufacturer or get it from a shop that you know and trust. Avoid online discounts from unknown sources. Top quality rubber will retain its power for many shot cycles, and will exhibit very little energy loss when the bands remain loaded on your gun throughout the day. Poor quality rubber will break down faster, and will also experience a significant drop in power as the bands sit on your loaded gun for an hour or more. The last thing you want is to pull the trigger on a dream fish only to miss or injure it because your bands didn’t have the power.
* Band color is a myth!! It is common in the spearfishing world to hear statements like “black bands are softer”, or “I use amber bands because they are more powerful”. These days, bands can come in a variety of colors made by an array of manufacturers. Some are high quality, and some are very poor quality. The only thing you can be guaranteed is that the color of the bands has nothing to do with it!*
Configuration
How many bands should you be using on your gun? One, two, six, ten? As you might have already guessed, it all kind of depends…
Often, less is more
Generally, less bands offer quicker, easier loading, and one or two bands is often all you need for most spearfishing situations. For many, many years, diving with a single band or two bands was the norm worldwide. Spearos simply changed the length of the gun and the diameter of the bands to have the right power for the situation. It wasn’t until big game blue water hunting really took off that divers started using large numbers of bands on big wooden guns to achieve the extremely powerful shots and long range necessary to tackle the world’s largest fish species. As a rule, most guns up to 130cm or 50” will work fine with one or two bands. Most european style guns (pipe guns) in this size range come stock with small diameter (7mm) shafts which can easily be overpowered by heavy bands or large numbers of bands. To get the most out of guns like this, 2 x 14mm or 2 x 16mm bands in the proper length are all you should need. Some divers like to use a single 18mm or 20mm band for these setups, mostly because one band is quicker and easier to load than two. The tradeoff is that a single heavy band when paired with a small diameter shaft will tend to be less accurate than the same gun set up with two narrower bands. If you have a long rail gun (120cm +) that you want to power up with more than two bands, it is important to balance that extra power with a larger diameter shaft that will have enough mass and rigidity to maintain accuracy. It is also worth noting that many euro style gun barrels, particularly aluminum ones, are not designed to withstand the pressure of several power bands pulling on one side of the barrel. A thin-walled gun barrel can flex noticeably under the intense pressure of an extra band or two, reducing the gun’s accuracy and potentially leading to failure.
Until more is more
There are situations in spearfishing that simply call for the biggest, most powerful guns. American blue water hunters figured out early on that a heavy 11/32” shaft propelled by several bands has enough mass and kinetic energy to reach out great distances and put the hurt on tuna, marlin and other massive bluewater species. Remember, however, that power like this comes at a price. Newton’s 3rd law states that for every action, there is an equal and opposite reaction. Firing a big, heavy shaft out of a speargun rigged with multiple bands = major recoil! Recoil when firing a speargun comes in two forms: primary recoil (the gun traveling backwards as the shaft travels forward), and secondary recoil (an upward motion of the muzzle as the bands contract and reach the front of the gun). Both forms of recoil affect the shot. The energy from primary recoil will travel back into your hand and arm, impacting the accuracy and consistency of your shot. Secondary recoil will generally cause a spear to veer downward as the muzzle of the gun rises while the spear exits the barrel, creating a predictably low shot.
Well designed guns address both of these problems through mass and ballasting. Most guns designed with the power to hunt large blue water game fish have several things in common. They are long (55-70”); they are made of heavy hardwoods like teak and mahogany; and they are ballasted (buoyancy compensated) using internal weighting systems. Many also feature large wooden “fins” that run laterally alongside the barrel. All of these features are designed to minimize recoil and create a stable launching platform for a heavy spear.
Bottom line, if your goal is to launch a big heavy spear at big nasty fish, you’re gonna need a bunch of bands, but before you go buying an 11/32” custom made shaft with a Mori slip-tip and loading up on more power bands than you’ve had girlfriends, make sure your gun is up to the job.
If you’ve got the cannon sorted, the number and diameter of the bands will mostly depend on the length and thickness of the spear (the overall mass). Less mass means less power is necessary to get the thing moving. For most bluewater setups 4 x 14 mm bands will have plenty of juice to get the job done and you will benefit from easier loading and less recoil. Longer, heavier shafts might necessitate adding an extra band or two, or using beefier 16 mm bands. Obviously, less bands and thinner bands will reduce your gun’s profile, making it easier to maneuver, and give you a cleaner sight picture. A good rule of thumb is to use the smallest and least bands you can get away with while still getting the desired accuracy, range and penetration.
Rigging Up
So, you’ve figured out your desired band number and thickness, and you’re ready to build some power bands. Before you begin, take a moment to watch this short video about how to make the bands.
There are just a few things you will need to get the job done:
Wishbone material (high quality 2 mm dyneema cord is a good choice. Do not use metal wishbones).
Cord for tying constrictor knots (I prefer flat waxed nylon braid, but there are many choices here).
Wishbone insertion tool or needle nose pliers.
2 pair of needle nose pliers.
Sharp scissors.
Lighter.
Silicone lubricant or soapy water.
Your desired speargun rubber.
Measuring Band Length
Once you’ve gathered all of these items, the first thing you will need to do is figure out the length to cut your rubbers. Here we will focus on building rubbers for open muzzle spearguns which use a single length of rubber looped through the muzzle and connected at the ends by a wishbone.
Step 1 - Place the spear shaft into your speargun and make sure it is locked into the mech. Measure the distance between the opening in the muzzle (where your bands are anchored), and the furthest loading tab or notch. Multiply by 2 (because there are rubbers on both sides), and subtract your wishbone length. Typical wishbone length is 2-4 inches or 5-10cm. Go shorter for smaller guns/less rubbers, and longer for bigger guns/more rubbers. The resulting number will be the length of your bands on one side of the gun when fully stretched.
Step 2 - Divide the result by your stretch factor. Most speargun bands perform well when stretched to 3 times their original length, so dividing by 3 is a good place to start. Some bands are capable of delivering optimal power when stretched to higher factors such as 3.5-3.8, but use caution, as overstretching your speargun bands can make the gun harder to load, shorten the lifespan of your rubbers or cause them to fail.
This will give you the correct measurement to take when cutting your bands.
Here is an example:
I have measured 100cm from the band slot of my speargun to the rear sharkfin tab, and I want my bands to be stretched by a factor of 3 when loaded. I like my wishbones short, so I will be making them 5cm long.
L1 - Length from band slot to notch or sharkfin
W - Wishbone length
S - Stretch factor
((L1 X 2) - W) / S = Cut Length
((100 X 2) - 5) / 3 = 65
I will be cutting my bands for this gun at 65cm
Making and Inserting Wishbones
There are many ways to make wishbones, but to keep things simple I’ll outline the method I believe is the fastest and easiest.
Step 1 - Cut a piece of wishbone material slightly longer than your preferred length to accommodate the knots you will tie in both ends. The goal is to have the correct length of material in between the knots.
Step 2 - Tie a double overhand knot in each end. Before you pull the knots tight, measure the length of the wishbone and then adjust as necessary to achieve your desired length.
Step 3 - Grab one end of your band material and prime it with lube by coating the end of your needle nose pliers and inserting into the opening in the band. Remove the pliers, and use the wishbone insertion tool or the pliers to press one end of the wishbone about 1.5 cm into the rubber.
Step 4 - Cut a 6-8” length of constrictor cord and tie your constrictor knot about ½ cm from the end of the band, rotating the band as you pull to tighten the knot.
Step 5 - Cut a second length of constrictor cord and tie another constrictor knot directly over the first one, ensuring the cut ends end up on the opposite side of the rubber.
Step 6 - Burn all 4 cut ends close to the rubber. Be careful not to damage the rubber with your flame!
Thread your rubber through the muzzle opening and repeat this process on the other side to finish your band.