Revolution Design Pty Ltd.

Derwent Park, Australia

Revolution Design Pty Ltd.

Derwent Park, Australia
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Jacobi G.,University of Tasmania | Thomas G.,University of Tasmania | Davis M.R.,University of Tasmania | Davidson G.,Revolution Design Pty Ltd.
Journal of Marine Science and Technology (Japan) | Year: 2014

The slamming behaviour of a large high-speed catamaran has been investigated through the analysis of full-scale trials data. The US Navy conducted the trials in the North Sea and North Atlantic region on a 98 m wave piercer catamaran, HSV-2 Swift, designed by Revolution Design Pty Ltd and built by Incat Tasmania. For varying wave headings, vessel speeds and sea states the data records were interrogated to identify slam events. An automatic slam identification algorithm was developed, considering the measured rate of change of stress in the ship's structure coupled with the vessel's pitch motion. This has allowed the slam occurrence rates to be found for a range of conditions and the influence of vessel speed, wave environment and heading to be determined. The slam events have been further characterised by assessing the relative vertical velocity at impact between the vessel and the wave. Since the ship was equipped with a ride control system, its influence on the slam occurrence rates has also been assessed. © 2013 JASNAOE.


Haase M.,University of Tasmania | Binns J.,University of Tasmania | Thomas G.,University of Tasmania | Bose N.,University of Tasmania | And 2 more authors.
Transactions of the Royal Institution of Naval Architects Part A: International Journal of Maritime Engineering | Year: 2012

A new class of fuel-efficient and environmentally friendly twin-hull vessels is currently under development. Compared to high-speed catamarans, a significant reduction in speed combined with an increase in deadweight tonnes will lead to a highly efficient medium-speed catamaran design. Recently-built conventional and high-speed ferries are compared to each other in terms of length, speed, deadweight and transport efficiency to classify the new design. The goal of this study is to find a preliminary macro design point for minimum total resistance by considering the main particulars of the catamaran vessel: block coefficient, prismatic coefficient and slenderness and separation ratios of the demihulls. Publications containing recommendations towards the optimum hull form parameters for moderate Froude numbers are reviewed and existing experimental data analysed to identify parameters for this new class of vessel. Designs with varied L/BOA-ratios and constant deck area are compared to find configurations of low total resistance for carrying a nominated deadweight at a particular speed, the associated change of the light ship weight has been taken into account. Two different model test series of catamaran models have been considered and their resistance curves agreed to each other. Recommendations are made; with the most important being the vessel should not exceed a speed of Fr = 0.35, with optimal prismatic coefficients around C P ≈ 0.5 and low transom immersion. This study presents the preliminary design of medium-speed single and twin-hull vessels for operations close to hump speed. © 2012: The Royal Institution of Naval Architects.


Jacobi G.,University of Tasmania | Thomas G.,University of Tasmania | Davis M.R.,University of Tasmania | Holloway D.S.,University of Tasmania | And 2 more authors.
Transactions of the Royal Institution of Naval Architects Part A: International Journal of Maritime Engineering | Year: 2012

To assess the behaviour of large high-speed catamarans in severe seas, extensive full-scale trials were conducted by the U.S. Navy on an INCAT Tasmania built vessel in the North Sea and North Atlantic region. Systematic testing was done for different speeds, sea states and ride control settings at different headings. Collected data has been used to characterise the ship's motions and seakeeping performance with respect to wave environment, vessel speed and ride control system. Motion response amplitude operators were derived and compared with results from a two-dimensional Green function time-domain strip theory seakeeping prediction method. An increase of motion response with increasing vessel speed and a decrease with the vessel moving from head to beam seas was found. In higher sea states and headings ahead of beam seas an increasing influence of the centre bow on pitch motion damping was found. Significant motion RAO reduction was also found when the ride control system was active. Its effectiveness increased at higher speeds and contributed to heave and pitch motion RAO reduction. Predicted motion magnitudes with the time domain seakeeping code were consistent with the measured motion responses, but maximum heave was predicted at a rather higher frequency than was evident in the trials. © 2012: The Royal Institution of Naval Architects.


Matsubara S.,University of Tasmania | Thomas G.,University of Tasmania | Davis M.R.,University of Tasmania | Holloway D.S.,University of Tasmania | Roberts T.,Revolution Design Pty Ltd
11th International Conference on Fast Sea Transportation, FAST 2011 - Proceedings | Year: 2011

Knowledge of the magnitude of expected sea loads, particularly slam loads, is a critical component of optimising the structure of large high-speed vessels. Of vital importance is an understanding of the vessel motions since they will directly influence the loads and also the comfort of the passengers and crew. A segmented model of a wave-piercing catamaran has been designed and constructed to obtain experimental values of global motions and loads. Results are presented for the motions, global wave loads and slam loads, with a particular focus on the influence of the centrebow configuration. The motions were found to be distinctly non-linear with respect to wave height; this was due to the immersion of the centrebow in larger waves tending to reduce the heave and pitch motions. The wave loads were found to be dominated by the slam load on the centrebow, varying in magnitude and location with respect to wave conditions. © 2011 American Society of Naval Engineers.


Davis M.R.,University of Tasmania | Lavroff J.,University of Tasmania | Thomas G.A.,University of Tasmania | Davidson G.,Revolution Design Pty Ltd.
Proceedings of the 18th Australasian Fluid Mechanics Conference, AFMC 2012 | Year: 2012

High speed multi-hull ferries can experience strong vertical motions near the bow when encountering heavy seas and risk bow damage due to deep entry into encountered waves. The risk of water passing over the top of the bow has been virtually eliminated in the INCAT Tasmania Wave Piercer design which incorporates a centrebow with a keel on or above the waterline. However, confinement of displaced water in the connecting archways to port and starboard of the centre bow leads to large hydrodynamic loads on the bow structure. The time dependant water entry problem for a high speed wave piercer vessel is extremely complicated owing to the relatively complicated form of the bow areas of the hulls. Determination of the hydrodynamic loads which can occur has therefore been based primarily on experimental testing at full scale and at model scale, but CFD methods are also being investigated. As the bow enters an encountered wave, water is at first displaced by the centre bow and ejected over the top of the forward ends of the demi-huills. However as the water entry event develops the rising water surface can ultimately fill the arch cross section and at that stage the hydrodynamic loads can become extremely large. Maximum loads in excess of the total displacement of the vessel (that is in excess of 2500 tonnes at full scale typically) have been observed and have durations of about 0.4 seconds at full scale.


Haase M.,University of Tasmania | Iliopulos F.,University of Tasmania | Davidson G.,Revolution Design Pty Ltd. | Friezer S.,Stuart Friezer Marine Pty Ltd. | And 5 more authors.
Proceedings of the 18th Australasian Fluid Mechanics Conference, AFMC 2012 | Year: 2012

Medium-speed catamarans are the latest development in fast marine transportation. Reliable methods to estimate the calm water performance and to predict the powering for the full scale vessel are necessary. For this paper RANSE-based methods were used to predict the total resistance for medium-speed catamarans for various hull forms, speeds and scales using both an open-source and commercial solver. For the Froude numbers of interest (0:3 < Fr < 0:5) an absolute relative error of 10% and below could be achieved compared to model and full scale test results.


Iliopulos F.,University of Tasmania | Lavroff J.,University of Tasmania | Davis M.R.,University of Tasmania | Binns J.,University of Tasmania | And 2 more authors.
FAST 2013 - 12th International Conference on Fast Sea Transportation | Year: 2013

The scope of the present work is to investigate the validity of CFD simulation for the prediction of the resistance for high and medium speed RoPax catamarans. The case study considered here concerns INCAT Tasmania hull 061, an aluminium built catamaran driven by a set of 4 steering Wärtsilä water-jets The hull studied here has been considered bare and thus the conditions during the sea trials, from where the data for the correlation is sourced , may not be effectively replicated in a CFD virtual towing tank. Despite these limitations, this work shows the potential for using full scale CFD simulations for an initial estimation of the powering requirement of a high speed Wave Piercing Catamaran. The outcome of the work is promising since fair agreement is found between the CFD and full scale data. Nevertheless, the CFD modelling is complex owing to the number of variables involved and it remains the case that CFD must be used with caution.


Shahraki J.R.,University of Tasmania | Thomas G.,University of Tasmania | Penesis I.,University of Tasmania | Amin W.,University of Tasmania | And 2 more authors.
FAST 2013 - 12th International Conference on Fast Sea Transportation | Year: 2013

Wave-piercing catamarans are used extensively for both defence and commercial sea transportation. Advantages such as large deck area, stability and high speed make these catamarans suitable for transporting roll-on roll-off cargo and passengers. However, issues such as the impact of the bow into the water when operating in large waves, better known as wetdeck slamming, can affect their mission capability and can cause structural damage. Different strategies are used by the designers to reduce wetdeck slamming in catamarans. Wave-piercing catamarans often have a centrebow that provides reserve buoyancy under the wetdeck in the bow to reduce heave and pitch motions and avoid deck diving in following seas. Designing an efficient centrebow is crucial for these vessels to reduce motions and minimise structural loads. To evaluate the effect of various hull forms on motions and slamming loads, a hydroelastic segmented model was designed and constructed. This segmented model is a scaled model of a 112m INCAT wave-piercing catamaran and has two transverse cuts and a separate centrebow. The centrebow segment was equipped with two six degree of freedom force/torque sensors to allow for slam loads to be measured. Three centrebow volumes (lengths) were designed and tested in head seas in the AMC towing tank in regular waves. The results show a significant variation in slam loads when comparing the three centrebow lengths, with the highest loads found on the longest centrebow, caused by larger water volume constrained between the centrebow and demihulls. Results also showed that the longer centrebows have higher pitch motions in slamming conditions.


Haase M.,University of Tasmania | Davidson G.,Revolution Design Pty Ltd | Thomas G.,University of Tasmania | Binns J.,University of Tasmania | Bose N.,University of Tasmania
Ship Technology Research | Year: 2013

Medium-speed catamarans are under development as a new class of vessels to meet requirements for highly efficient sea transportation with low environmental impact. Reduced service speed and increased deadweight will increase transport efficiency. Compared to current high-speed catamarans, these new vessels will operate in a transitional speed range between high-speed craft and conventional displacement ships. In this paper, design guidelines to choose appropriate main dimensions for medium speed catamarans with minimum resistance were derived and a preliminary design was made. These vessels will operate at Froude numbers of about 0.35 and have a relatively low prismatic coefficient of about 0.5 in conjunction with a small transom immersion. Different methods are discussed to correctly predict the calm water resistance, with RANSE (Reynolds-averaged Navier-Stokes equations)-based flow simulations being the most promising. It is shown that they are capable of predicting the hydrodynamic characteristics of medium-speed catamarans, such as drag force, trim and sinkage with acceptable accuracy.


Haase M.,University of Tasmania | Binns J.R.,University of Tasmania | Bose N.,University of Tasmania | Davidson G.,Revolution Design Pty. Ltd. | And 2 more authors.
Transactions of the Royal Institution of Naval Architects Part A: International Journal of Maritime Engineering | Year: 2015

Large medium-speed catamarans are a new class of vessel currently under development as fuel-efficient ferries for sustainable fast sea transportation. Appropriate data to derive design guidelines for such vessels are not available and therefore a wide range of demihull slenderness ratios were studied to investigate the design space for fuel-efficient operation. Computational fluid dynamics for viscous free-surface flow simulations were utilised to investigate resistance properties of different catamaran configurations having a similar deadweight at light displacement, but with lengths ranging from 110 m to 190 m. The simulations were conducted at full-scale Reynolds numbers (log(Re) = 8.9-9.6) and Froude numbers ranged from Fr = 0.25 to 0.49. Hulls of 130 m and below had high transport efficiency below 26 knots and in light loading conditions while hulls of 150 m and 170 m showed benefits for heavier displacement cases and speeds up to 35 knots. Furthermore, the study concluded that the lowest drag was achieved with demihull slenderness ratios between 11 and 13. © 2015: The Royal Institution of Naval Architects.

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