Investigation of planing craft maneuverability using full-scale tests

Abstract

Maneuverability of planing craft is a complicated hydrodynamic subject that needs more studies to comprehend its characteristics. Planing craft drivers follow a common practice for maneuver of the craft that is fundamentally different from ship’s standards. In situ full-scale tests are normally necessary to understand the maneuverability characteristics of planing craft. In this paper, a study has been conducted to illustrate maneuverability characteristics of planing craft by full-scale tests. Accelerating and turning maneuver tests are conducted on two cases at different forward speeds and rudder angles. In each test, dynamic trim, trajectory, speed, roll of the craft are recorded. The tests are performed in planing mode, semi-planing mode, and transition between planing mode to semi-planing mode to study the effects of the craft forward speed and consequently running attitude on the maneuverability. Analysis of the data reveals that the Steady Turning Diameter (STD) of the planing craft may be as large as 40 L, while it rarely goes beyond 5 L for ships. Results also show that a turning maneuver starting at planing mode might end in semi-planing mode. This transition can remarkably improve the performance characteristics of the planing craft’s maneuverability. Therefore, an alternative practice is proposed instead of the classic turning maneuver. In this practice, the craft traveling in the planing mode is transitioned to the semi-planing mode by forward speed reduction first, and then the turning maneuver is executed.

Simulation of Turning Manoeuvre of Planing Craft Taking Into Account the Running Attitude Change in a Simplified Manner

“…Figure 22 shows the path of the turning manoeuvre where STD/L was 34.9. The forward speed decreased from 36.50 knots to 29.5 knots [24].…”

“…21, where the STD/L was 34.00 and 17.80 at a rudder angle of 14° and 20°, respectively. The forward speed decreased to 34.00 and 30.00 knots at a rudder angle of 14° and 20°, respectively [24].…”

“…Although the heave and pitch strongly affect the four other motions during a manoeuvre, they are marginally affected by the four other motions. As far as the impact of the four other motions on the heave and pitch are concerned, one may conclude (from Sadati et al [24]) that the yaw, sway and roll velocities are much smaller than the surge velocity during a steady turning manoeuvre. Therefore, the heave and pitch motions are dominated by the surge velocity, which is almost equivalent to the speed of a craft.…”

“…Therefore, the heave and pitch motions are dominated by the surge velocity, which is almost equivalent to the speed of a craft. Additionally, Sadati et al [24] showed that the trim angle in a straight path is almost equal to the pitch during a steady turning condition in the planing regime.…”

“…We conducted full-scale manoeuvring tests on two boats (Case A and Case B) and the results have recently been published [24]. The boat in case A had a length of 15.4 m and a weight of 11.0 tons.…”