**
The Effect of Deadweight
**

© 2001 Atkinsopht (02/15/03)

Increasing displacement weight reduces speed owing to the increase in wetted
surface at the higher displacement and, further, increasing deadweight reduces
speed owing to a reduction in the shell velocity excursion - which reduces the
available external momentum work delivered to the footboard.
Below is a table of the pertinent data from the model ROWING for a coxed
eight:

Case 1 Case 2 Case 2a: @ equal power
------ ------ ------
Displacement weight, Ww, kg 805 885 * V2= V1 [Ww1/Ww2]^0.167
Deadweight, Wd, kg (non-sliding) 220 225 V2= V1 [Wd1/Wd2]^0.500
----- -----
Shell speed, V, m/s V1: 5.85 V2: 5.76 5.71
----- ----- -----
Rating, 1/min 30.1 30.1 29.5
Peak oarhandle pull, N 630 630 630
Shell w.l. length, m 17.85 17.91 17.91
Shell w.l. beam,m 0.58 0.59 0.59
Reynolds' number 8.7E7 8.6E7 8.6E7
Block coefficient, Cb 0.42 0.42 0.42
Prismatic coefficient, Cp 0.53 0.53 0.53
Hull resitance factor, N-(s/m)^2 12.74 13.28 13.28
Oarlock work, J/stroke 4344 4323 4306
Ftbd. momentum work, J/stroke 800 792 796
Shell friction work, J/stroke 5144 5115 5103
Total rower power, Watts 525 540 524
System efficiency 0.615 0.594 0.599

* Agrees with
**the "Effect
of Weight in Rowing"**, Section 7. Effect of Deadweight on Boat Speed.
The speed penalty for added weigt is slightly greater if the comparison is
made at constant total rower power (Case 2a) in which case the stroke rate is
necessarily relaxed slightly.