The torpedo sinker is probably one of the most commonly used and sought after fishing weight. There are a few reasons why the torpedo sinker is so common, and although its a similar shape to the “trolling weight” they arent identical.
Lets start with the shape –
#1) The torpedo weight (sometimes called the inline sinker) has a slender, symmetrical shape with a brass eye at each end. This shape is somewhat like a missile, narrow at each end and slightly fatter in the middle.
This slender shape allows this fishing weight to drop quickly and get to into the strike zone where you are targeting the species you’re after – quickly. This slender shape also allows the weight to be trolled, with minimal resistance, thus allowing a consistent motion through the water keeping your bait in line. Lastly, when it comes to fishing things like breakwalls/jettys this thin smooth shape keeps the torpedo sinker vertical dropping through tight cracks in between rocks preventing snags. The key with this type of fishing however, is to not quite let your line slack much, as to keep the sinker vertical. When you retrieve it back, be slow, and patient so as to keep the weight vertical when coming through cracks and chasms between the rock piles.
#2) The torpedo weight is sometimes also referred to as the double ring sinker… Why? Unlike most fishing sinkers, the torpedo sinker has 2 eyes or points of attachment. One at each end of the sinker, allowing for a variety of applications. By having two opposite points of attachment, the torpedo sinker can be used “in-line” ( hence the name inline sinker). This means you tie your line to one end, and can run a leader with a lure, bait, etc to the other end. You can also utilize the double rings by turning the torpedo sinker into a custom made lure. Simply add some pain, a skirt, some flash, etc… and put a split ring with a hook on one end, or a siwash hook… and on the other end you have the eye where you can tie your line.
#3) The torpedo sinker can occasionally be used as a trolling weight, depending on the speed youre going and the type of fish. You could essentially rig a torpedo up like a premade trolling weight by adding a short section of wire leader, and shock leader to each end, using a heavy swivel. The wire leader is important as wahoo will occasionally bite the torpedo thinking its a fish, snapping off the line. The cable prevents that. If you dont have the gear to make a custom wahoo trolling lure using a torpedo sinker, then Just buy a premade wahoo trolling weightThese premade trolling weights are very expensive compared to using a basic torpedo sinker and rigging them up yourself with cable, shock leaders and swivels. Often the most common size for high speed wahoo trolling is 24-48 oz, which can be purchased through Ocean-Angler .
As far as the what many specialists would consider a true trolling weight, it would be similar to the picture above. A slightly more slender shape is generally what is used. This allows for even less resistance when trolling at high speeds. Rather then a brass eye on each end, the trolling weight will have a cable running through it on both ends, fused into the casting. It will have a heavy wire loop or swivel at each end, and a snap swivel on the other end. This makes it simply for the fisherman to just simply tie onto their shock leader, and they are ready to go and fish!