A day in the Fitzroy

[Douglas]

P1060011.jpg

Time for some pix. (Comics are always more interesting than novels).

The one thing that stands out like the proverbials on soft plastics is the size of the vibration generator (the tail flapper) when its pulled through the water.

Its positioned at right angles to the intended direction of travel (back towards the rod). The tail is thin and soft/pliable so that when moved, the surface of tail bends slightly allowing water to spill around the side and commence the vibration.

Because the tail flapper is thinner at the edges, it will bend at the edges first. One edge bends (could be either but one will go first) which creates a lower pressure on that side and drags the flapper in that direction. Lets say it goes right.

The shaft of the tail then counteracts that to pull the flapper back towards the centre where the other edge then starts to bend pulling the flapper to the left.

Then away the lure goes with the flapper tail swinging right then left. Like a soldier marching.

The magnitude and frequency of the vibration created will depend on the surface area of the flapper.

No matter what tricky remedies the manufacturer sets up to make up for the lack of surface area, unless he's got a decent flapper surface area to start with he is operating from a handicap right from the start.

Have a look at the lures shown in the pix.

From left to right we have increasing sizes of tail flappers (vibration generators). That means increasing surface areas available to flap.

These are all roughly the same shape so it should be easy to come up with some sort of "figure of merit" as vibration generators when compared with each other. Not absolute figures but relative figures (to each other).

I've compared them all with the little pink one on the left so I called it a Figure of Merit (FOM) of 1.

Then the others fell into place easily:

. pink one........ 1

.grey.............. 1.7

.white squidgy....3.3

.thumper......... 1.5

. spinner blade....3.5.

To add to the list yourselves just measure the dimensions of the flapper in mm and divide the result by 154. That'll give you a FOM which is the basic starting point for all of these devices.

Naturally, the bigger the flapper, the bigger the potential figure of merit.

This is a very simple starting point for soft plastics with a flapper tail. Things can change a bit when enhancements are introduced like positioning of the jig head to produce body roll (like a slick rig squidgy) or a bulbous tail like a thumper. But the basic principle of how much the potential that tail flapper has, wont change.

Pretty simple stuff here and I guess you could say that you see that just looking at the tail flapper and you'd probably be close to right. This simply gives a starting point referenced to something.

However, the ball game really changes when you get into hard body lures.