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50ft oh casts, comparison incl. and excl double haul

Purpose

The purpose of this comparison is to show the impact of double haul, dhl.

The comparison is made between two simulations:

· The 50ft oh ref. cast simulated without dhl.

· “50ft dhl” simulated with dhl. Double haul denotes the hauling of line during the casting stroke and the release of line from the rod during the pause. Here, the line length for the simulation with double haul is up to 0.50 m longer than for the 50ft reference cast. The peak haul velocity is 5.0 m/s and is set 110 ms after the max angular velocity.

Input, casting stroke

The line haul velocity and line feed velocities, shown below, are the only inputs that differ between the two compared cases. For the 50ft oh ref. cast, haul and feed velocities are both zero.

Input, equipment

The equipment for both simulations is identical, see the 50ft oh ref. cast.

Output, animation

Click on the graph below to start animation.

Comment, animation:

The haul increases rod loading/bending during the acceleration phase and this contributes to increased line speed. Another benefit of the haul is the decreased loop radius leading to decreased air drag. It is noted that the haul must not be excessive as that may lead to a dip in the rod tip path and as a consequence tailing loops.

Output, graphs

The graphs considered most relevant for the comparison are presented below. For explanations to the graphs please see the 50ft oh ref. cast.

Output, energies and work

Notes on energies and work:

· The increase in work input by the caster for the dhl cast is partly due to increased bending moment at the rod handle and partly due to the added work by the hand hauling line.

· The rod strain energy is increased for the cast including double haul. However, the increase in line kinetic energy is significantly larger than the increase in rod strain energy indicating that most of the increase in work input by the caster “goes directly to the line” and only a smaller portion via increased “strain energy stored in the rod”.