**
The Mass Added to a Rowing Shell Hull **

by the Bound Fluid Layer

© 2004 Atkinsopht (09/01/04)

It is time that someone (a graduate student; a rowing club?) determine the
mass added to seated shells by virtue of the bound fluid layer- for singles,
pairs, fours, and eights.
For any well appointed rowing club this is something that would not be hard
to do (but might be frustrating in its details). I agree to **post on this
site** the results of any serious attempt to fill this gap in the knowledge
of rowing.

The determination of the mass of the (seated) shell alone is a matter
of simple weighing of the boat, oars, and crew.

The determination of the added mass can be approached either
theoretically or empirically.

A theoretical approach might involve the estimation of the average
thickness of the bound layer from the laws of fluid dynamics for various
hulls and multiplying those by the wetted surfaces and the fluid density.
It might then be repeated for a range of hull speeds and boats to form a
parametric function which could then be used in any model.

However, an empirical approach might enable the *direct*
determination of the added mass by "weighing" the boat and its bound
layer together by inertial means. I think this is relatively easily
possible.

Suppose a (seated) shell to be set in motion in still water by the
application of a known constant force (a falling weight?) and the
resulting acceleration noted at various stages during the resulting speed
increase. The net mass accelerated at each stage (including that of any
bound layer) is then a matter of simple calculation (m=F/a); and that
"added" the result of subtracting out the known dead weight of the
(seated) hull.