Sink Tips and Sink Rates [Archive] - Fly Fishing Forum

: Sink Tips and Sink Rates


jimS
07-13-2003, 02:25 PM
Conventional wisdom relates grain weight to sink rate, e.g. a 750 grain head sinks faster than a 250 grain. Does that mean that a 10 pound weight dropped off a 10-story building falls faster than a one pound weight? I don't think so.

The same analogy applies to grain weight and sink rate. Bill Dawson, a rep for Rio, began this discussion recently at my local flyshop, Oil Creek Outfitters. To compound the midunderstanding, throw in the various sink rates, type 1 (intermediate or slow) to type 8 (fast).

The last few years I used a Rio Striper 350 grain sinktip until I lost it on a good fish when the backing snapped. This year I began using a Rio Striper 300 grain sinktip. This new generation sinktip actually sinks faster than last year's model. This was confirmed to me by dragging bottom in the same depth and current that was not possible with the 350.

Simms

loco_alto
07-13-2003, 02:34 PM
interesting analogy, but friction is the wrinkle. As the coefficient of friction increases (in this case, with water, though we move into Stokes Navier equations) then an object's density takes on increasing importance for terminal velocity

In other words, those 2 objects falling through air will have a more similar velocity than those 2 objects falling through water.

SO yes, different grain heads (with similar diameter, thus different density) will sink at different rates. Skinner lines matter a lot, which is what gives Tungsten and LC13 such a fast sink rate

jimS
07-13-2003, 06:05 PM
Good points relative to mass of an object in water. Thus, a fat 750 grain line could have a slower sink rate than a skinny 250 grain line.

One other point I failed to mention is that if all else is equal, i.e. a 450 gr has the same sink rate as a 300gr, then the decision on which one to use is dictated by the rod weight that you are using. You can cast a 300gr with an 8wt, but you would be taxing that rod with a 450gr.

Simms

juro
07-14-2003, 08:29 AM
Great discussion!

I use sinktips extensively for spring and winter steelheading and have found by far that smaller diameters with higher densities get right down to biz.

The same applies to sinking heads which is really what we are talking about here (vs. tips).

Since I am now experimenting actively with powerful two-handed rods designed specifically for the coastal fishery, more grains is not a problem because that lower hand makes even a 12wt feel easy. But get over 400 grains and the problem is the way the head behaves, not the rod throwing it.

I've found the biggest problem with grainy lines in the 26-30' range, 400 or greater, is that they cast like crap! Regardless of how well you can cast that head is going to whip around like a hose with the sprinkler cut off until it slaps the water. This doesn't happen for me with the 225, 250, 300, 325 or 350 but once you hit the 400 mark forget it.

Loco - what's the science behind that?

Eddie
07-14-2003, 09:55 AM
It has been said many times befor: LC-13 and now 14 sinks faster than anything under 600gr. This is good because if you want to cast the really heavy lines (450+), your 9 and 10 wt won't cut it. Around 30' of either casts great, pulls any fly, and sinks faster to boot. Thinner line sinks faster.
This holds true for the running line too. A fat floating running line doesn't help much. Mono running line sinks like a stone, but doesn't handle so great.
My go to fast sinking outfit is about 30' of LC-13 in front of Rio's .030 clear intermediate running line. It makes a big difference when you need to get down.
I have been useing LC-14 (new from Rio) and it is also good stuff. Maybe better suited for a 10wt. I think that my next running line will be the .035 Clear Rio intermediate. I will trade some distance and depth for improved handling.

MarkS
07-14-2003, 10:02 AM
As mentioned the real key for sink rate is density....

I use RIO shooting heads almost exclusively for subsurface work...and you can really see the difference when looking at the different lines...

On my 8-wt, I use 10wt shooting heads (all of which weigh about 300grains more or less (maybe 330, I can't remember)

The clear intermediate is fat, and sinks at about 1-2ips

The type III head is medium and sinks about 3-5ips

The type VI is skinny and sinks about 7-9ips.

I will also huck 27' of LC-13 on this rod (about 350 grains) and this sinks faster still.

Length does play an issue here too, but since we are almost always using heads that are roughly the same length...think density. The 12 wt Type III head that I throw on the 10wt, weighs a lot more than the above type III head but doesn't sink much faster.


mark