  We describe a method, based on techniques used in molecular dynamics, for
simulating the inertialess dynamics of an elastic filament immersed in a fluid.
The model is used to study the "one-armed swimmer". That is, a flexible
appendage externally perturbed at one extremity. For small amplitude motion our
simulations confirm theoretical predictions that, for a filament of given
length and stiffness, there is a driving frequency that is optimal for both
speed and efficiency. However, we find that to calculate absolute values of the
swimming speed we need to slightly modify existing theoretical approaches. For
the more realistic case of large amplitude motion we find that while the basic
picture remains the same, the dependence of the swimming speed on both
frequency and amplitude is substantially modified. For realistic amplitudes we
show that the one armed swimmer is comparatively neither inefficient nor slow.
This begs the question, why are there little or no one armed swimmers in
nature?
