Facts About Fishhook Patterns, Sizes, and Gauges

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Photo courtesy of Mustad.

In the world of terminal tackle, there is an astounding array of fishhooks available, many quite similar and many vastly different, and the number of patterns and sizes is impressive and confusing. Here are facts about patterns and sizes that will help you when choosing and using a hook.

Bend/Pattern

A pattern is the name by which a style of hook is known, and this is a function of its bend, which is the curved section between the point and the shank.

The bend has a lot to do with the strength of the hook. Ideally a hook should resist bending up to a stage where the hook almost would break, preferably bending instead of breaking. 

Resistance to direct-pull pressure is influenced by hook style and size, is substantially aided by forging, and is related to the bite and gap. The gap is the distance between the tip of the point and the shank. The distance from the peak of the bend to the gap is known as the bite or throat. Most hooks have a deep or relatively deep bite and a fairly wide gap, both of which keep hooked fish more secure than a shallow bite or narrow gap.

Most hooks avoid having a sharp angle to the bend and are such that the initial stage of the bend is gradual and the final stage of the bend is pronounced. This is actually less easily bent than a symmetrically round design.

Here are some popular patterns and their attributes:

  • Sproat: straight point; popular with flies and lures.
  • Kirby: point offset helps prevent hook from slipping out; good for bait fishing.
  • O'Shaughnessy: outward bend to the tip of the point; heavy wire; many applications.
  • Aberdeen: light wire, round bend good for use with minnows; will bend before breaking.
  • Carlisle: stronger than Aberdeen; used with bait; long shank prevents fish from swallowing the hook.
  • Siwash: heavy wire; extra long point offers good retention; used for big, active fish.
  • Salmon Egg: short shank; concealed by small bait.
  • Claw or Beak: point is offset and curved inward to aid penetration; used often with bait.
  • Limerick: long shank; wide bend provides extra hooking space.

There are many more patterns, of course, and many with very specialized applications. Freshwater bass anglers, for example, have such an affinity for fishing with soft lures, especially worms, that there is a whole genre of so-called worm hooks (which should not be confused with fishing with natural worms) having various humps and bends to the shanks, as well as different bends and worm rigging enhancements.

One of the more specialized products is a circle hook, which has become very popular in bait fishing. The circle hook has a wide bend and long inward point that at first glance makes you wonder how it could ever stick a fish, but it not only does, it also doesn’t pull out very easily under fishing rod pressure, so a greater number of fish hooked are landed. Perhaps more importantly, as circle hook is especially good at hooking a fish in the corner of the mouth and not deep in the throat, minimizing harm and making it less injurious to fish that will be released.

Size/Gauge/Temper

No matter what the pattern, hooks are all designated according to size, which in principle is the width of the gap. This is just a relative designation, however, instead of an absolute one. Gap width may differ between families of hooks and there is no consistency between manufacturers in sizing, so the matter of size designation is relative to individual manufacturers and specific patterns.

Sizes are specified in whole numbers at the smaller end of the spectrum and as “aught” fractions as they get larger. The smallest hooks, depending on manufacturer, are No. 32, 30, or 28; the largest hooks range from 14/0 up to 19/0.

Although it isn’t reflected in size designations, the diameter of the wire used to make the hook has a bearing on its performance and its proper use. This diameter is reached in manufacturing by taking steel wire rods and reducing them to the wire gauge that is necessary for a particular pattern.

The wire is pulled through a series of ever-narrowing orifices, which reduces the gauge, sometimes by as much as 90 percent.

There are fine, medium, and heavy wire gauges corresponding to relative diameter. Heavy wire is used in making hooks for the strongest applications and where it is beneficial for a hook to sink fast (large wet flies, for example, or big game bait fishing). Fine wire is used in making hooks for light-line fishing, angling with small and delicate baits, and in slow-sinking or floating uses. Medium wire is used for general purpose hooks.

In the manufacturing process, the drawn wire gets machined into shape and then heat-tempered. Tempering is the hardening process that gives the material its strength within that shape. It is a critical operation, as over-tempering results in soft hooks that don’t adequately resist bending and under-tempering results in hard hooks with no flexibility. The ideal is a strong hook that will flex moderately; if there is no flex under load the hook will snap at less of a load. (Incidentally, with the exception of some light wire hooks, like the Aberdeen, when a hook bends out of its original shape and does not spring back it is permanently deformed and should be discarded.)

Some hooks are also given extra strengthening by forging, which is stamping the sides flat. While this increases resistance to bending on a straight pull, it does not help resist side torque, and is often not found on hooks with offset points for this reason, since offset points do not resist side pressure as well as straight points.

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