Experimental study of hydrodynamic performance of a Monohull Planing vessel equipped by combined transverse step and transom wedge in comparison with a model of no appendage

Abstract

One of the most well-known strategies to eliminate or reduce the longitudinal instabilities in planing hull, is to reduce the trim of the craft. In the current study, porpoising is controlled through creating a transverse step, and the combination of adding a wedge to the stern and transverse step in the vessel. Usually, performance of stepped boats is not suitable in preplaning regime. However, through the proposed method, stepped model performance can be improved prior to the planing regime. The investigated craft is a 2.56 m long monohull high speed model with speed range of 1,3,5,7 and 9 m/s. The obtained results indicate that best performance is acquired by the step and wedge model at the beginning of the planing regime. From 3 to 7 m/s, drag of stepped and wedged models has the lowest value and above 7 m/s and at 9 m/s, the stepped model has the lowest resistance. Among the investigated methods, using combined step and wedge indicates largest reduction in trim angle (At speeds of 3 to 9 m/s). It can therefore be concluded that model equipped by combination of wedge and step improves the poor performance of the stepped models prior to the planing regime.

Numerical Study of the Effect of Angle and Location of the First and Second Steps on the Performance of Planing Hull and Their Optimization Using the Taguchi Statistical Method

“…Te step location efects in double-stepped hulls with transverse steps at speeds of 10 and 12 m/s were also numerically investigated by Ghadimi et al [36] and validated by some experimental tests. Te efectiveness of steps and wedges on planing mono-hulls would lead to the idea of using them simultaneously, which was probed by Sajedi et al [37] in an experimental manner with a step at 30% of vessel length to the vessel stern and a stern wedge with a height equal to 5% of the vessel beam. Tey found that the simultaneous use of stern wedges and transverse steps could improve the vessel's undesirable performance prior to planing regime, which is one of the challenges in planing hull design.…”

“…Tey found that the simultaneous use of stern wedges and transverse steps could improve the vessel's undesirable performance prior to planing regime, which is one of the challenges in planing hull design. Tese extensive data [9,28,29,[31][32][33][34][35][36][37] for diferent confgurations of a single parent model present a unique opportunity to realize how diferent confgurations of step and wedge could afect a planing hull's performance.…”

Experimental study of the effects of Vee-shaped steps on the hydrodynamic performance of planing hulls

“…The study of Zou et al 13 demonstrated that having a flap on double-stepped hulls could delay the porpoising speed with the penalty of resistance increase. Sajedi et al 14 mounted a stern wedge on a single-stepped hull and tested the craft at longitudinal Froude numbers ranging from 0.19 to 1.74. This simultaneous use of stern wedge and single step would enable planing hull designers to compare their combined effects with those of their individual effects.…”