Although it was not possible to capsize the model in natural waves in the Race, this series of tests confirmed an important conclusion presented in reference 1: if a drogue is used, it should be deployed from the stern rather than from the bow. With the drogue deployed from the stern, the model lay stern to the wind and sea. When the same drogue (or sea anchor) was deployed from the bow, the bow tended to fall off whenever the towline was slack. A 2-foot parachute (28 ft. diameter full scale) was tested in an effort to hold the bow into the sea but this did not make a significant improvement. The bow continued to fall off when the boat was in the trough.
The remainder of the tests were conducted in the Thames River. Without a drogue, the model would lie abeam to the wind. When struck by the wake of the boat, the model would be violently capsized, rolling through 360 degrees. It was obvious that there was much more energy in the wave crest than was necessary to marginally capsize the model.
With the 6-inch diameter drogue deployed from the stern, the model was pulled stern first through the breaking wave with no capsize in most instances. However, for several wave strikes the towline had so much slack that the model was capsized before the drogue exerted any force. It is probable that this result is an artefact of the test situation since in actual storm conditions the boat will be riding large regular waves, and the towline should have little slack as the next wave crest approaches.
The deflection of the spring-loaded vane to which the towline was attached was determined by analysis of the movie frames. For two of the runs the vane deflection has been converted to pounds force and the results are shown on Figure 6. It will be noted that the maximum load for one of the runs is about equal to the displacement of the model, whereas for the other run the load is less than half the displacement. In the latter case the model was farther from the research boat and the wake had less energy.