Steps can improve the hydrodynamic performance of planing boats in both calm and rough conditions. While transverse steps have been widely studied, the influence of swept (V-shaped) steps remains less understood. This paper presents a mathematical model to predict the calm-water performance of a hard-chine planing boat equipped with forward-swept steps. The method is based on the 2D+T approach and uses a linear wake assumption to estimate the ventilation length behind each step. Model predictions are validated against experimental measurements and CFD results. The validated model is then applied to assess the hydrodynamic performance of swept-stepped hulls in early-stage design and to support designers in optimizing step height, sweep angle, and longitudinal position for improved trim, reduced resistance, and enhanced overall performance. The study extends and validates the 2D+T method for forward-swept configurations, offering a fast and practical tool for concept evaluation, while CFD remains essential for final design refinement.

This study investigates the potential for improving the dynamic performance and human safety of High-Speed Planing Craft (HSPC) in irregular head waves through the implementation of a Transom Interceptor System (TIS) and a Double Interceptor System (DIS). Experimental tests measure hull resistance, heave and pitch motions, and vertical accelerations in semi-planing, transient, and planing modes. The recorded data for the bare hull, the hull equipped with TIS in transient mode, and the hull equipped with TIS and DIS in planing mode are compared to evaluate the interceptor performance in improving the dynamics of HSPC. Additionally, the crew safety exposed to vertical acceleration is evaluated according to the ISO 2631–1 (1997), ISO 2631–5 (2004), and EU Directive 2002/44/EC (2002). The results indicate that TIS effectively enhances dynamic performance in transient and planing modes as well as human safety and comfort by reducing moderate vertical acceleration. However, in transient mode, TIS may amplify impact shocks, increasing the possibility of adverse health effects. Moreover, the DIS increases hull motions, vertical acceleration, and the potential for health and comfort risks in planing mode. These findings emphasize the potential of TIS in enhancing HSPC dynamics and safety, while it is crucial to optimize interceptor configurations based on operational speeds.

Interceptor is a high-lifting device used in high-speed crafts to correct trim angle and, to some extent, reduce hull resistance. Double Interceptors System (DIS) is an unconventional configuration that involves two interceptors, one is installed on the transom and the other in the middle of the hull length. This design can lead to a higher reduction in drag and trim angle, though designing and implementing efficient DIS requires a thorough understanding of its hydrodynamic performance. This study uses the SIEMENS PLM StarCCM+ code to numerically simulate high-speed craft with and without DIS in calm water and presents the effects of DIS on hull trim angle, drag, and pressure distribution on the hull bottom. Furthermore, the effects of different interceptor heights on its efficiency have been investigated. The accuracy of the current models is examined by comparing the measured trim angle and drag against the experimental results of towing tank tests provided by De Luca and Pensa, (2012a). The obtained results revealed that using DIS causes an unwetted surface area behind the forward interceptor, consequently reducing the wetted surface area and shear drag. Moreover, a high-pressure region appears when the water flow encounters the interceptor, which can affect the pressure drag. As this high pressure does not lead to a rise in total drag, it can improve lift force distribution and longitudinal stability.

A 150 m electric wave-piercing catamaran concept from Incat Tasmania is analysed using CFD to explore the hydrodynamic impact of operating speed and hull separation on vessel performance and CO2 emissions reduction. Over the investigated speed range of 0.2 < Fr < 0.4, interference factors are evaluated for four demihull separation ratios (s/L) and two demihull slenderness ratios (L/∇1/3). The implications on total life-cycle CO2 emissions are presented as a function of total vessel resistance, and the significance discussed. A separation ratio of s/L = 0.220 provides the lowest overall resistance, however other configurations provide superior results for specific Froude numbers. The concept of transportation capacity is introduced and used to demonstrate the advantage of slower speeds for the electric powertrain through identification of a critical Froude number Fr = 0.35, above which transportation capacity is reduced as a consequence of the low energy density of Nickel Manganese Cobalt (NMC) batteries. A comparison is also made between the electric and equivalent LNG and diesel powertrains to demonstrate the effect of fuel carbon intensities on standardised vessel CO2 emissions. Through analysis of the transportation capacity and emissions reduction of the electric vessel, a speed of Fr = 0.28 is proposed as a compromise between the two, with further power and emissions reductions achievable near this speed by adopting a narrower hull separation ratio of s/L = 0.151.

Traditional planing hulls have been a standard in maritime design, yet recent innovations in modern high-speed craft have introduced alternative hull configurations, including tunnels, hydrofoils, and energy-saving devices such as interceptors. The selection of the appropriate hull type has become a critical consideration in the preliminary design phase. In scenarios where ship owners demand increased deck space without compromising speed, designers may propose planing catamaran hulls, characterized by two (demi) planing monohulls connected by a tunnel. These high-speed catamarans offer large spaces making them optimal for diverse military and transportation applications prioritizing spaciousness. The selection process involves a thorough evaluation based on performance, maneuverability, fuel efficiency, and cost-effectiveness. Given the popularity of both planing monohulls and catamarans in high-speed crafts, this paper investigates mathematical models for predicting the performance of catamaran planing hulls. While the mathematical models draw inspiration from planing monohulls in calm water, they consider the interference location and effects between the two half-bodies in catamaran designs by incorporating separation effect parameters. Specifically, this paper explores the implementation of the 2D+T method for the early-stage hydrodynamic design of catamaran planing hulls by using two methods. The first method employs sectional pressure distributions to calculate three-dimensional forces in calm water, the second utilizes momentum variation along the vessel for calculation of three-dimensional forces. In the final stage, a verification comparison is conducted, investigating unsteady Reynolds-Averaged Navier-Stokes (RANS) computations. The findings contribute to engineering community by providing hydrodynamic tools and results that can be used in conceptualizing the design of a high speed craft.

Verification and Validation (V&V) is the foremost analysis which is carried out for evaluation of the accuracy level and dependability of computational fluid dynamic (CFD) simulations. The present study investigates the V&V of CFD models in predicting the dynamic trim and hull resistance of high-speed planing hulls with an aim to provide a deeper understanding of V&V analysis in this specific field of application. Two different planing hulls, namely the C05 stepped hull and the C1 interceptor hull, are analyzed with four different grids and time-steps using two mesh motion techniques, namely overset and morphing approach. The discretization (grid) and time-step uncertainties for each CFD simulation are estimated using the least squares method. The results indicate that the overset mesh approach performs better than the morphing grid method in terms of numerical uncertainty and validation achieved for both hulls. The error of both techniques in the prediction of resistance and trim angle of the boat shows an acceptable range of accuracy. The findings provide valuable insights for simulation-based designing and optimizing high-speed planing hulls, specifically by identifying the optimal mesh technique, cell number, and time-step for accurate prediction of wetted surface shape, ventilation formation, running attitude, and resistance.

This paper investigates the maneuvering characteristics of a planing hull free to move in heave and pitch directions undergoing a steady drift test. Results assess and compare predictions from Computational Fluid Dynamics (CFD) Detached Eddy Simulation (DES) and a 2D + t strip theory models against available experimental data from Katayama et al. (2005). At high yaw angles and high Froude numbers of predictions from both models marginally deviate from the experimental longitudinal force measurements. Whereas strip theory confronts difficulties in predicting dynamic trim angle and CG rise-up when either Froude number or yaw angle increases and hence nonlinear hydrodynamics prevail, CFD generally agrees well with experimental data. The CFD model is seen to result in numerical ventilation in zero-drift cases, leading to lower pressure and a localized reduction in the skin friction coefficient. These phenomena are hypothesized to contribute to the under-prediction of trim angle and longitudinal force in zero-drift scenarios. Strip theory provides less reliable results in terms of predicting the sway forces at larger yaw angles, the yaw moment at low Froude numbers and sway forces and associated maximum pressures near the stagnation line. This model cannot capture the asymmetric pressure distribution that emerges on the bottom of the hull at large speed and yaw angles, which is likely to be one of the reasons for errors in predicting the side force. Detached Eddy Simulations demonstrate the strong asymmetric vorticity field formation on the exposed side of the hull at nonzero drift angle. This means that added masses used in the 2D + t model can cause large errors in equilibrium predictions.

Predicting the dynamic responses of planing hulls in real sea conditions is important for identifying how basic design factors influence their seakeeping performance. Hence, there is a pressing need to provide high-fidelity models for predicting the motions of these hulls in random waves, representing actual seas. In this article, a computational-based model for solving viscous fluid flow around the vessel is built to address this problem. Three different planing hulls, denoted as C, C1, and C2, each distinguished by the number of steps incorporated on their bottom surfaces (1 and 2 indicating the respective step count, with case C being the stepless hull), are modeled in a Computational Fluid Dynamics (CFD) tank, allowing for analysis of the effects of steps on dynamic responses of a planing surface operating in random waves. CFD data is compared against those collected in towing tank tests, revealing a satisfactory level of accuracy. Extreme value and gamma distributions are shown to give probabilities of maxima/minima of displacements and vertical acceleration at the center of gravity (CG) for all three hulls. It is shown that the stepless boat may be exposed to lower vertical acceleration at an early planing speed, but at higher planing speeds, a double-stepped design mitigates the vertical acceleration. Nevertheless, the double-stepped hull would experience more significant extreme heave responses across all speeds and may be exposed to less significant extreme pitch responses during the ride at the highest speed compared to the stepless and one-stepped hulls. The skewness of heave and pitch is evaluated, and it is found that the heave response tends to skew toward positive values (upward). This skewness becomes more noticeable with increasing speed but remains insensitive to wave steepness. Additionally, the pitch response at lower planing speeds shows a partial skew towards negative values (bow-down), but eventually, they may also be partially skewed towards positive values at higher speeds. Moreover, a correlation is observed between the kurtosis of responses of different hulls and the occurrence of the 1/100 highest responses, indicating that a kurtosis greater than 3.0 would result in more extreme responses. Overall, this analysis offers practical insights into planing hull behavior in actual sea conditions from a CFD model perspective, highlighting the potential of CFD in simulating this complex problem.

An innovative Computational Fluid Dynamics (CFD) approach, defined as the Forcing Function Method (FFM), is used to simulate Ride Control Systems (RCS) on an Incat Tasmania Wave-Piercing Catamaran vessel in analysis conducted at model scale. This study examines the FFM's capabilities in head sea regular waves using CFD, and considers three ride control scenarios: Bare Hull (BH), Pitch Control (PC), and Non-Linear Pitch Control (NL PC). CFD-predicted vessel motion is compared to experimental data from a 2.5 m Incat Tasmania Wave-Piercing Catamaran model at 2.89 m/s (Fr∼0.6), showing good agreement. Modification in FFM to account for emergence of control surfaces from the water, and time series of lift forces produced by FFM are also discussed. The frequency domain analysis using heave and pitch Response Amplitude Operators (RAOs) showed a good of agreement in motion reduction trends between CFD and experiments, providing a high level of confidence in the FFM predictions. Dimensionless vertical accelerations are calculated along the length of hull using the various control algorithms, showing a considerable reduction in acceleration, especially at the bow. These outcomes demonstrate the novel CFD approach, FFM, that can be used by ship designers for predicting high-speed vessel motion reductions from deployment of RCS, and thereby improving passenger comfort.

Moving fast by high-speed planing craft (HSPC) is advantageous for some special missions, though it causes severe hull vibrations and shocks that can transfer to the human body and increase health and comfort risks. This study reviews the current safety standards to avoid human safety risks affected by whole-body vibrations (WBVs), as well as the safety status of HSPC occupants. In addition, the efficiency of motion-reduction devices (trim tab and interceptor) and shock/vibration-mitigation devices (shock-mitigation seat) in improving the safety of HSPC occupants is examined according to existing documents. The research methodology was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRIS-MA) method, and published papers in the Scholar, Scopus, and Web of Science databases were analyzed. Because most of these publications are academic research, issues of bias in the eligible publications were not of particular interest. During this systematic review, many gaps and challenges in current information on safety improvement devices were found that need to be addressed in future studies, such as a lack of information on motion-reduction devices and shock-mitigation seat performance in reducing lateral and fore-and-aft motions. Referring to these gaps and challenges can be valuable as a suggestion to improve current knowledge in research and reduce safety risks.