You might find it helpful first to read Casting in Fog on Just One Week, which clarifies all the terminology.

The set up of floating line, polyleader and mono tippet is commonly used. Indeed, I've caught 80+% of my salmon using that approach. There are a couple of things to bear in mind with polyleaders. First, their sink rate is measured in static water, so they don't sink as fast or as far in moving water, which generates hydrodynamic lift. In essence, you won't get very deep with a polyleader: for example, with a 10' brown fast sink polyleader in medium paced water and a conventional double fly, it's likely you will be fishing at a depth of around a foot at the mid-point of the swing. Second, longer sinks further than shorter. For example, a 5' green slow sink polyleader will only take your double fly 5-6" below the surface, which is no more than you will achieve with a 12' fluorocarbon tippet. Third, most salmon rivers are generally quite shallow (apart from specific deep pools); we tend to overestimate the depth in front of us; a taking salmon will come up 5-6' to your fly; and you need to present your fly above the fish for reasons of detectability and visibility.

The main reasons for using a polyleader are to get your fly down through the surface turbulence to achieve a smooth presentation; and to ease the casting turnover of larger and heavier flies. They're not the answer on those rarer occasions when you need to get deep.

Going seriously deep is the domain of sinking lines. Sinking tips on a floating line are a compromise, but while useful, easy and flexible, they don't get you down very far. You need to go heavy in deep water; in cold water in spring when salmon tend to lie near the bottom; or to counteract the effects of very fast flows. But unless you're fishing big rivers like the Tweed, Tay and Spey in early spring, or in Norway where the pace of the water is unlike anything you encounter in UK, you are unlikely to need a sinking line very often and you may not need to make the investment.

 

Jimmy thank you for taking the time to write and send such a detailed answer, its much appreciated, my local river and the river i fish the most is a small spate river and like you said it's not a paticularly deep river apart from the odd pool around 10/12 foot , so as far as set up goes there's nothing wrong with it ? Just expect to be fishing in the first foot or so , with say a 8 ft fast sink poly , in medium paced water ?

 

We get this sink rate think rolled out every time poly leaders are mentioned as though it’s some absolute down fall. The sink rates of all lines tips and indeed poly’s are worked out the same way in a static pool. The thing to absorb is it’s the same sinking polymers used in polys as in multi tips and fly lines.
Yes of course you can only expect any 10ft poly of any sink rate to only get so deep and a 10ft poly of the same sink rate as a 15ft tip or full line will never match them for depth seeking capabilities.
In all honesty the Hover, Inty, Green and Brown Airflo polys are best used for controlling the depth of the flee in the top 1ft of water, the two faster polys will help you get deeper, however they can be harder to cast and present and poly nay sayers generally shy from them.
One further thing is to realise is polys are thinner than equivalent full lines and multi tips so usually sink more than a lot of people realise.
I’m a big poly user fan, I use them just about most of the time and I find them of great benefit to managing fly depth from a floating line, and by that I mean the same fly fished in the same manner.
This isn’t a dig at anyone at all, just an opposing view to the poly conundrum. I’m sure if you take the time to learn about them and use them to their best, they’ll reward you.
No offence intended to MCX either here, we all have our views of what works for us.
Pedro.

 

 

Thanks Rennie , this gives me confidence in the set up , thank you

 

Pedro , another big sticking point for me at the mo is the using the correct length of tippet material off your poly leader , i know it all depends on the depth and fly your fishing , but say a 8ft intermediate poly with a size 10 double ? 5ft 6ft leader ? Fast sinking poly , say 4ft / 3ft tippet ?

Cheers

 

You’ll be fine with what you’ve quoted there Hyde44.
Pedro.

 

 

Don't forget that casting 90 degrees across, then putting in two big downstream mends will get the fly further down. Particularly if you use a weighted fly on a short tippet.

What doesn't work in putting a long tippet and a light fly on a sink tip. The current just pushes the fly up.

 

Nice one mate
Cheers 👍

 

Another consideration is that adding a 10’ extension to the head of your fly line changes a lot of things about the cast.

Kit lines like the RIO and Airflo design the extra length and weight into their total line profile but adding a polyleader to a line that's supposed to be balanced, unbalances it. I remember accidentally adding a 12’ floating tip onto a line that already had a 12’ floating tip on. Absolute pig to cast and took me ages to figure out what was wrong.

Sink tips also sink when you don't want them to; leave them on the water half a second too long during a cast and you're stuffed.

Sorry, closed season withdrawal ramblings…

 

Just a further point or two on polys in general.Most of the time it's 10 ft I use, 8ft are cool on switch rods, 5ft I only use as an addition to a 15ft multi tip or full sinking line to further knock the flee down a little and give me a more controlled droop to the tip in the water. 15ft polys I find don't work that well as the tapers are all wrong and too fine for too long in their length.
Another key part of using polys is a longer tapered leader on a fly line is no bad thing to aid in anchor when Spey Casting and also giving better turn over in final presentation.
Of all the fly lines I have it's only the most ridiculously fast of sinkers that don't benefit from their addition- usually because the polys aren't fast enough. I'd also hasten in adding, it's rare in the UK to need fly lines that sink faster than 6ips.
All my multi tip lines I use with polys in place, usually 10 ft but also 5ft too, I find they all cast better with polys in place- that includes Rio, Guideline,Cortland, Hardy and Airflo and it has to be said offer greater flexibility when used with the existing tips.
Pedro.

 

While we are on the subject of poly leaders, my main shooting head range are the SCSS heads from LTS in the full array. Have full sets of these for all my rods from switch to 16’. Instead of using their 10’ tips I use 10’ extra strong airflo polys and a leader from around 6-7’ for tubes up to the length of the rod for dressed flies. Cast perfectly well with perhaps even a benefit in presentation at a fraction of the cost of the dedicated tips (I’ve 2 full sets of those and it’s rare they see light of day)

 

I like to mix and match and find stuff that works together.
Get a good feel for heads and tips and all sorts of combo’s work.
15ft fast sink polys - great with old guideline scandi intermediate heads when the water is a bit on the high side. Or with game changers when the waters’ a bit higher. Higher than that get the T tips out and/or full sinkers.