International Shipbuilding Progress - Volume 70, issue 1

Authors: Wellens, Peter

Article Type: Editorial

DOI: 10.3233/ISP-230608

Citation: International Shipbuilding Progress, vol. 70, no. 1, pp. 1-2, 2023

Authors: de Kwant, Jochem | Hekkenberg, Robert | Souflis-Rigas, Apostolos | Kana, Austin A.

Article Type: Research Article

Abstract: This article examines the potential implications of using iron powder as an alternative fuel on the design and performance of container ships. Iron powder is a relatively new alternative energy carrier and one in which little research has been done into the application on-board vessels as part of the maritime energy transition. The key benefits of iron powder are that it is a circular energy carrier and the combustion process emits no greenhouse gases. Transitioning to iron powder is expected to have far reaching implications for the design and performance of ships. Thus, this paper aims to perform the first …study assessing the potential of this concept applied to container ships. To do so, a preliminary design space was explored with a custom parametric design model developed to generate preliminary designs of iron fuelled container ships as a function of the operational profile. Using this parametric design model, it was identified that iron fuelled container ships are weight limited, unlike conventionally fuelled container vessels. Furthermore, iron fuelled container ships are best suited for short voyages at low cruising speed. For these voyages, it was concluded that iron fuelled ships are economically feasible; however, other alternative marine fuels are likely more profitable than iron due to the low efficiency of iron fuelled ships and the high cost of iron per unit energy. Show more

Keywords: Iron powder, alternative fuel, container ship design, design space exploration, feasibility study

DOI: 10.3233/ISP-220012

Citation: International Shipbuilding Progress, vol. 70, no. 1, pp. 3-28, 2023

Authors: Ozeki, K. | Nakahara, S.

Article Type: Research Article

Abstract: The colonization of barnacles on surfaces has detrimental effects on shipping, leisure vessels, heat exchangers, oceanographic sensors, and aquaculture systems. One strategy for avoiding barnacle colonization on surfaces is to utilize surface wettability. Silicone-incorporated diamond-like carbon (Si-DLC) has high hardness and a low friction coefficient, and an increase in the incorporation of Si leads to hydrophobicity. By contrast, oxygen plasma treatment produces hydrophilicity in Si-DLC films. The improved surface wettability of Si-DLC may reduce barnacle colonization. However, few studies have been conducted on barnacle larval settlement in relation to Si-DLC films. The aim of this study is to evaluate …barnacle larval settlement on Si-DLC films and on oxygen-plasma-treated Si-DLC films. Si-DLC films were prepared by radio-frequency plasma-enhanced chemical vapor deposition and treated with oxygen plasma. The films were characterized using Raman spectroscopy and X-ray photoelectron spectroscopy. Contact angles of the films were measured to evaluate their hydrophobicity. Barnacle cyprid larva settlement was observed on the Si-DLC and oxygen-plasma-treated Si-DLC films. The contact angle of the Si-DLC-0% film was 69.9 ± 3 . 3 ∘ and increased with Si incorporation. Following oxygen plasma treatment, the contact angle of the Si-DLC-0% films decreased to 10.9 ± 4 . 4 ∘ and gradually increased with Si incorporation. The barnacle cyprid larval settlement ratio for the non-coated stainless plate was 36.4%, whereas that of the DLC films was 15.0%, which decreased with Si incorporation. Following oxygen plasma treatment, the ratio of barnacle cyprid larval settlement in Si-DLC films was lower than for the Si-DLC films. The Si-DLC film was effective in avoiding barnacle adhesion, whereas the oxygen-plasma-treated Si-DLC was even more effective. This study demonstrated the feasibility of Si-DLC for antifouling against barnacles. Show more

Keywords: Barnacles, oxygen plasma, silicon-incorporated diamond-like carbon, contact angle, surface wettability

DOI: 10.3233/ISP-220008

Citation: International Shipbuilding Progress, vol. 70, no. 1, pp. 29-40, 2023

Authors: Zwart, Robert H. | Bogaard, Jordi | Kana, Austin A.

Article Type: Research Article

Abstract: Trim optimization improves the energy efficiency of ships, thus reducing operational costs and emissions; however, trim tables are only available for a limited number of ships. There is thus a desire to develop additional, more accurate trim tables without the need for expensive model testing. The objective of this research was to develop a method to decrease fuel consumption by trim optimization, by a dynamic shaft power estimation model based on available operational data. A method that uses noon report data and a grey-box modelling approach is proposed. The grey box model consists of a multi-layer feedforward neural network to …estimate the required shaft power, using operational parameters and an initial estimate of the required shaft power. A case study is presented for a modern chemical tanker and sea trials have been conducted to validate the results. The method provides correct trim advice for full load conditions; however, the magnitude of the effect is smaller compared to sea trial results. The model is able to estimate the required power with an average accuracy of over 6% for a random subset of the noon report data. Due to challenges inherent to noon reports as a data source, the actual effect of trim and speed have a bigger magnitude than the extracted trend. Show more

Keywords: Trim optimization, grey-box modelling, sea-trial validation, noon reports, chemical tankers

DOI: 10.3233/ISP-220009

Citation: International Shipbuilding Progress, vol. 70, no. 1, pp. 41-63, 2023