Your friend is catching fish, but you’re stumped. From a distance, you shout back and forth, “How deep are you?”, “What flies?”....Then the final piece of the puzzle, “How much weight”? What response do you get? Maybe, “A small one”, or “3 big ones”. Would it be more helpful if they said, “2 Number 4’s, but a BB would work too”. You’re damn right it would, but how many of us know the weights? Ya me neither… I just guess until I think I’m getting closer. But maybe we can springboard our understanding of split shot and help each other out a little more.
No4, BB, AB...WTF
First, split shot is sold in different sizes. They have a numbering scheme, so I’m just going to leave a conversion table below. Print it out and take it with you on the river. There is also a column to compare sizes.
Don’t Be Mislead by Density
Next, split shot seems to fall into 3 categories for materials, tungsten (usually puddy), lead, and non-toxic tin. Each element has a different density, and each sink at different rates. To start, the density of water is 1 g/cm3. So the greater the density, the faster it will sink in water. Here is how these three elements stack up.
- Tungsten (W): 19.25 g/cm3
- Lead (Pb): 11.342 g/cm3
- Tin (Sn): 7.287 g/cm3
Fortunately, split shot is measured by mass (grams) and not density. And following good old physics:
Mass = Density x Volume
So a highly dense Tungsten split shot wouldn’t need as much volume to equal the same mass as required by a Tin split shot, because it has a greater density. Regardless of the differences in densities, a 0.4g (BB) Lead split shot, should be the same as 0.4g (BB) Tin split shot, etc.
Don’t be fooled that you need to go buy tungsten split shot to get a faster sink rate, any split shot of the same mass, should sink the same. A Tin split shot might just be larger than the Tungsten version. That being said, a larger split shot will have a greater surface to be blown by the current.
Note: This doesn’t apply to beadheads, as beads are restricted by hook size, so the volume is fixed in this case, making the difference in a material’s density influence the flies overall mass in the end.
Toxic Lead PSA
Lead split shot still exists out there, but please go find some non-toxic alternatives. Lead split shot has reaped surprising havoc on waterfowl, mostly due to anglers. Why? Many bird species, like the Common Loon, mistakenly gather split shot into their gizzards to help them digest fish and bones. Since Loon eat fish whole, they have a specialized organ, a gizzard, in which they ingest rocks to help physically break down bones and fish parts. The problem is, Loon tend to find these split shot (and other lead-based fishing products) and ingest them. And like the effects on humans, Lead absorption has drastic effects on birds. Between 1989-2012, 44% of Loon mortality was linked to Lead found in fishing products. I didn’t even understand how bad the effects of Lead split shot are, and am currently moving away from those products. President Obama went so far as to propose a Lead ban on federal lands, but the rule was overturned during the Trump Administration...