The debate over using a single hook-set versus a double hook-set is decades old. Everyone has their own theory as to which is better.
When I first started game fishing 30-plus years ago, the go-to marlin lure was the scoop-faced 550 Kona head in green-and-yellow. It was rigged on six feet of 275-pound, 49-strand wire and a single forged 10/0 hook buried well in the skirt so the marlin couldn't see it. By today's standards it was a primitive rig but back then we didn't know any better, but we didn't land a great deal of fish. Our rigs were unsophisticated, the line classes often too light, and way too many fish got away.
Single hook rigs were pretty much standard the world over at that time, but as lure-fishing experiences of travelling anglers visiting the world's billfish hotspots trickled down, the single hook rig was replaced with double hooks rigged at zero, 60, 90 and 180 degrees, depending on the lure design and the preferences of the owner.
Prior to the crimping and leader systems we use today, snelling two hooks onto a heavy leader with the snap end finished off with a perfection loop was a primitive way of getting two hooks into a marlin lure. The rig saw moderate success, but marked the first of many steps forward.
Crews developed various double-hook rigs and these systems became the go-to and it was easy to see why. The double-hook fills the lure skirt better, it gets a hook point up near the head of the lure to deal with those annoying billfish that only like to scratch up the resin, and logic dictated that more hooks is better, right?
In hindsight, we lost a lot of marlin in the ensuing seasons on double-hook rigs, blue marlin in particular. Often times the hooks were lodged in the fish's jaw, but looped around and jammed on the marlin's bill. When the fish turned towards the boat, the rig slid off. We concluded that the second hook got in the way of the first hook setting correctly. Why two hooks would lead to foul-hooked or lightly hooked fish was a mystery, but the situation was more common than any of us could believe.
This was confirmed when we switched to Owner Jobu hooks and you could actually see where the black paint had been scratched off from the inside of the bend. Foul hookups on the bill have become less common since we crossed back to singles set towards the end of the skirt.
LESS IS MORE?
There are many advantages to running single hooks. First, once a single hook is set, it's usually in for good. A single hook won't button up a fish, hooking the fish in both the upper and lower jaw which doesn't do the fish any favors if it breaks free. Additionally, there is less rigging, fewer crimps and no heat-shrink.
Another positive feature of the single hook rig is safety. Having a second, unattached hook flying about while releasing a frisky marlin boatside is fraught with danger. Jamming a piece of swimming pool noodle or styrene foam over the spare hook certainly makes it safer, but you always know where you are with a single hook.
In big-fish locations like Cairns, Australia, fishing double hooks in lures is rarely, if ever, used. Besides, at $15 to $20 a pop, you don't want to throw two hooks away when one will do the job. We don't recover hooks from released marlin unless the fish throws it. It's too dangerous getting close to a feisty 800-plus pounder to remove the hook. Being steel, the hooks do rust out over time.
The Cairns single-hook rig is as effective as it is basic, and usually consists of a single galvanized 14/0 hook at the tail end of the skirt, with a #64 rubber band half-hitched onto the leader a couple of times to set the hook's position.
There are many variations on the general theme, but single-hook rigs are pretty simple to make. The hook needs to be well back in the skirt, as long as it is IGFA legal (part of the hook within the skirt material). Some deckhands like to really push the boundaries with just the eye of the hook in the skirt, but most go for half to two-thirds of the hook in the skirt.
To set the hook in the skirt leave a long tag when crimping the hook on, then twist the leader. Run the twisted tag end into a second crimp and set it in place. The second crimp rests against the lure head. Aside from setting the distance between the lure head and the hook, this crimp also doubles the abrasion resistance in a key area.
You can stiffen and reinforce the hook-set further by wrapping electrical tape around the hook eye or coat the hook-set with PVC cement (that blue glue plumbers use to join pipes). This basically serves as an extension of the hook shank, which should create a better hookup.
The leader is then tooth-picked, or pushed into a rubber bung that is glued to the back of the lure head to set the leader so the hook rides point-up for a solid hookup.
Hook size is dependent on the lure. For bigger marlin a single 12/0 should suffice. If striped marlin are the target, maybe a single 11/0 would be a better match. Ditto if there are other species likely to get involved with the lure spread during the course of the day.
In saying this though, there's an increasing body of evidence from crews with a lot more time on the water than most of us that a single small hook is producing better results than stepping up a size. Fad or fashion, it's certainly food for thought.
Now while single hooks appear to be the answer to a lot of lure hookup woes, there is a fair body of evidence to say that yellowfin tuna attack the head of the lure first, so in a mixed-species fishery a double-hook rig may prove advantageous.
Lures rigged this way halve the weight by doing away with one hook, a length of heavy cable wire, crimps and heat shrink. It might not seem like much, but on some days, especially those slick calm ones we all hope for this weight can make all the difference as to how a lure performs. As an experiment, take all the hooks off and watch how much better your favourite lures swim.
The curved-in point of the Mustad 7691S has long been a favourite 'Tail End Charlie' on double-hook rigs (the front one being a 7732S). Of course, it's really up to the angler as we all have our favorite patterns.
If going stainless, I prefer a Mustad or Dozer, and I never under any circumstances use look-alike copies. Inferior strength hooks in a double hook rig where one hook lodges in the top jaw and another in the lower can see one (or both) hooks bend like paperclips.
There's also the chemically sharpened option from the likes of Owner, but always remember to add a piece of sacrificial anode to the hook shank to protect the hook point or it will disappear in no time flat.