UNDERSTANDING THE URFE RIG

Get to grips with line diameter and hook sizes

Many readers enjoyed the two articles I wrote in issue 540 and 541 about the Urfe rig, but it prompted questions about the light lines and small hooks used in its construction.

Roy Sanders, of Slough, Berkshire, was confused about choosing line by diameter, in this case 0.25/0.20mm in summer and 0.35/0.30mm for winter.

Being used to buying line for its breaking strain, Roy tried to find a conversion chart, only to discover there are different conversion charts for mono to that of fluorocarbon, and between makers.

Well, as Roy noticed, the subject can be confusing. Firstly, there is only one true measurement on a spool of line, and that is its diameter. There are so many ways to test the breaking strain of line. These can include testing it over one metre, five metres, the breaking strain of the line spooled up on a reel or threaded through a rod. This is why you get such a wide range of breaking strains for the same diameter line.

Breaking strains can even vary on exactly the same product, depending on the country they are sold. Therefore, a one size fits all conversion table is impossible to create. Even if there was a standardised testing procedure, a conversion table wouldn’t help because there would be various breaking strains for a single diameter line depending on the maker.

As regards lines sold as rig body, fluorocarbon, fluoro leader and hooklength material, there is nothing defining what properties they should have. A company could use exactly the same line labelled as fluorocarbon in smaller diameters, and in bigger diameters for leader material.

Diameter gives me an idea of abrasion resistance; for instance, 0.20mm line will not last long over rough ground, so 0.40mm will suit it better. Diameter also gives a good idea of its strength. As an example, if you got snagged with 0.28mm line and it snapped; I doubt another 0.28mm line boasting a higher breaking strain would have pulled out of the snag. A heavier 0.35mm line might though.

Until there is a standard way of testing line, diameter is the most accurate and possibly safest way to buy and use the product. Before we had all sorts of fancy line and our choices were limited, this rough guideline in the table (below) was the mm/lb conversion. If you are worried about breaking strains, this conversion chart will be conservative and safe.