Sailing Research Articles

Review on the application of stainless-clad bimetallic steel in the marine environment

PurposeStainless-clad bimetallic steels (SCBS) are widely investigated in some extremely environmental applications areas, such as polar sailing area and tropical oil and gas platforms areas, because of their excellent anticorrosion performance and relatively lower production costs. However, the properties of SCBS, including the mechanical strength, weldability and the anticorrosion behavior, have a direct relation with the manufacturing process and can affect their practical applications. This paper aims to review the application and the properties requirements of SCBS in marine environments to promote the application of this new material in more fields.Design/methodology/approachIn this paper, the manufacturing process, welding and corrosion-resistant properties of SCBS were introduced systematically by reviewing the related literatures, and some results of the authors’ research group were also introduced briefly.FindingsDifferent preparation methods, such as rolling composite, casting rolling composite, explosive composite, laser cladding and plasma arc cladding, as well as the process parameters, including the vacuum degree, rolling temperature, rolling reduction ratio, volume ratios of liquid to solid, explosive ratio and the heat treatment, influenced a lot on the properties of the SCBS through changing the interface microstructures. Otherwise, the variations in rolling temperature, pass, reduction and the grain size of clad steel also brought the dissimilarities of the mechanical properties, microhardness, bonding strength and toughness. Another two new processes, clad teeming method and interlayer explosive welding, deserve more attention because of their excellent microstructure control ability. The superior corrosion resistance of SCBS can alleviate the corrosion problem in the marine environment and prolong the service life of the equipment, but the phenomenon of galvanic corrosion should be noted as much as possible. The high dilution rate, welding process specifications and heat treatment can weaken the intergranular corrosion resistance in the weld area.Originality/valueThis paper summarizes the application of SCBS in marine environments and provides an overview and reference for the research of stainless-clad bimetallic steel.

Swarm of lightsail nanosatellites for Solar System exploration

This paper presents a study for the realization of a space mission which employs nanosatellites driven by an external laser source impinging on an optimized lightsail, as a valuable technology to launch swarms of spacecrafts into the Solar System. Nanosatellites propelled by laser can be useful for heliosphere exploration and for planetary observation, if suitably equipped with sensors, or be adopted for the establishment of network systems when placed into specific orbits. By varying the area-to-mass ratio (i.e. the ratio between the sail area and the payload weight) and the laser power, it is possible to insert nanosatellites into different hyperbolic orbits with respect to Earth, thus reaching the target by means of controlled trajectories in a relatively short amount of time. A mission involving nanosatellites of the order of 1 kg of mass is envisioned, by describing all the on-board subsystems and satisfying all the requirements in terms of power and mass budget. Particular attention is paid to the telecommunication subsystem, which must offer all the necessary functionalities. To fabricate the lightsail, the thin films technology has been considered, by verifying the sail’s thermal stability during the thrust phase. Moreover, the problem of mechanical stability of the lightsail has been tackled, showing that the distance between the ligthsail structure and the payload plays a pivotal role. Some potential applications of the proposed technology are discussed, such as the mapping of the heliospheric environment.

A Study on Price Prediction of Used Sailboats Based on XG-Boost Algorithm

The sailing industry is currently receiving more and more attention and there is a growing demand for sailboats. Their prices are constantly changing and inevitably contain useful trends and intrinsic correlations. Therefore, we developed a used sailboat price prediction model to allow relevant practitioners to better understand the sailboat market. First, we obtained some key data from the official websites of various sailboat manufacturers that may affect the price, including width, draft, displacement, sail area, headroom, and so on. We pre-processed the data. Next, based on the XG-Boost algorithm, we built a used sailboat pricing prediction model and estimated its accuracy, which reached about 91.5% in the test set. Finally, we did a one-way ANOVA on region and sailboat prices and found that there are significant differences in sailboat prices across regions. Therefore, we conducted a consistency test for region effects and found that the region effects for displacement and sail area were consistent.

Design framework for sail & rigging parameters of Bodrum Gulets: comparison of schooner and ketch configurations

ABSTRACT Bodrum Gulets are worldwide known sailing yachts, for their unique designs and cultural background that they have. In this paper, sail and rigging parameters of Bodrum Gulets with schooner and ketch type riggings are examined and parametric models are developed by using the data collected from 20 Bodrum Gulets with schooner and 27 Bodrum Gulets with ketch rigging configurations. Parametric models are used to compare sailing performances of two different sail and rigging types on Bodrum Gulets. The results show that, for the parametric model that obtained by using the hull form, sail and rigging parameters, the difference between sail area of ketch and schooner configuration is 14%. However, the polar graph shows that the difference between the hull speeds of two rigging configurations is in the range of 1.5–10%. Finally, a design framework for the hull, sail and rigging parameters of Bodrum Gulets is developed.

МОЖЛИВОСТІ ЗАСТОСУВАННЯ СОНЯЧНОГО ВІТРИЛЬНОГО ПРИСТРОЮ ДЛЯ ВІДВЕДЕННЯ КОСМІЧНИХ ОБ’ЄКТІВ ІЗ НАПІВСИНХРОННИХ ОРБІТ

The current state of the near-Earth space environment poses a threat to spacecraft moving not only in low and geostationary but also in semi-synchronous orbits. The main methods that can be used in these orbits for space debris removal are the active method using a rocket propulsion system and the passive method using a solar sail device. The last method is of particular interest because of the low overall mass and mass characteristics of the removal system, as well as the availability of unlimited solar light radiation, which can be converted into a driving force. Solar sails are currently undergoing experimental testing in the near-Earth space, but they have not been used for medium and high orbits. Two constructive variants of solar sails construction are considered: frame and rotor. The article is devoted to the evaluation of the possibility of removing space objects from semi-synchronous orbits using a solar sail. Two variants of the removal scheme are considered: into a circular disposal orbit 200 km below the target orbit and into the dense layers of the Earth's atmosphere. A computer simulation of the removal is performed using the example of the Galileo global positioning system spacecraft with a frame-type and rotor-type solar sail. The dependence of the orbit altitude at the ending of removal on the solar sail area was obtained. The values of the solar sail area required to provide for the maneuvering and the weight of the structure were determined. It was demonstrated that the total mass of the frame-type solar sail is 9 kg (1.3% of the spacecraft mass) and that of the rotary-type solar sail is 11 kg (1.6%). As applied to disposal into dense layers of Earth's atmosphere for frame-type solar sail - 52 kg (7.4%), for rotary-type solar sail - 25.5 kg (3.6%). It follows from the obtained results that for moving to the disposal orbit 200 km below the target orbit it is more advantageous to use a frame-type solar sail, and in the dense layers of the atmosphere - the rotor type.

Self-deployable drag sail folded nine times

• Folding method for 9 folds of the Highly Flexible Frames and the ability to deploy. • Experiments with the HFF in the pocket reviled the need for heat treating the steel. • Uncoiling of the HFF accrued, this was redeemed with a tight pocket depth. Increased focus on space debris push regulations by the UN and thereby the demand for debris removal systems to be implemented in future spacecraft. This research focuses on debris removal of post-mission satellites in LEO using drag augmented deorbit into the earth's atmosphere. By using gossamer sails (drag sails), aerodynamic breaking can effectively be achieved in LEO up to 700 km. The presented work supplements the research performed in the H2020 project Technologies for Self-Removal of Spacecraft (TeSeR), in which the Self-Deployable Deorbiting Space Structure (SDSS) has been further developed. It is devised how to obtain a self-deployable drag sail folded nine times for use in debris removal for a 6U CubeSat, i.e. an SDSS/9. Achieving nine folds of Highly Flexible Frame (HFF) is essential to maximize the drag sail area when it is unfolded and hereby increasing drag force. The nine times folded HFF has been modeled in computer simulations and demonstrated in a lab. From lab-based research, several issues have been identified when folding the HFF nine times. Of these, two main issues are addressed in this paper, i.e. relaxation and uncoiling. When folded nine times, the von Mises stresses computed by FEM reach 1857 MPa. Combined with residual stresses, this is causing yield and relaxation in the HFF and reducing the deployability. A minimum drag sail diameter is identified for this setup, and the high-strength stainless steel should be heat treated to relieve residual stresses before folding. A side-mounted design is chosen for the configuration of the SDSS. This reduces friction during the release and deployment of the drag sail. From thorough testing, it is observed that the uncoiling of the HFF during storage in the pocket significantly reduces the deployability of the SDSS. To mitigate both radial and axial uncoiling of the HFF in the pocket, the pocket diameter and height should be designed with an exact fit to the folded diameter and height of the ideally folded HFF with the drag sail included. Based on this research, a new design of the SDSS/9 for CubeSats is devised, and preliminary testing indicates good consistencies more test is necessary to determine the reliability of the side mounted SDSS. Hence, from the research, it is concluded that SDSS/9 is a feasible solution for a low-cost add-on debris removal system. Furthermore, the side-mounted design allows integration with additional collision protection of the spacecraft.

Performance Prediction Program for Wind-Assisted Cargo Ships

Wind-Assisted Propulsion Systems (WAPS) can play a key role in achieving the IMO 2050 targets on reducing the total annual GHG emissions from international shipping by at least 50%. The present project deals with the development of a six degree of freedom (DoF) Performance Prediction Program (PPP) for wind-assisted cargo ships aimed at contributing knowledge on WAPS performance. It is a fast and easy tool, able to predict the performance of any commercial ship with three possible different WAPS installed: rotor sails, rigid wing sails and DynaRigs; with only the ship main particulars and general dimensions as input data. The tool is based on semi-empirical methods and a WAPS aerodynamic database created from published data on lift and drag coefficients, which can be interpolated with the aim to scale to different sizes and configurations. A model validation is carried out to evaluate its reliability. The results are compared with the real sailing data of a Long Range 2 (LR2) class wind-assisted tanker vessel, the Maersk Pelican. The study indicates that the PPP shows good agreement with the technology suppliers’ own modelling tool and reasonable agreement with the trends of the real sailing measurements. However, for downwind sailing conditions, the predictions are more conservative than the measured values. Lastly, results showing and comparing power savings for the three different WAPS are presented. Rotor Sails are found to be the most efficient WAPS studied with a much higher potential of driving force generation per square meter of projected sail area.

Realistic sunshade system at L1 for global temperature control

So far, space-based geoengineering has rarely been studied from a practical point of view, considered unrealistic as a near-future alternative to fight climate change. This paper evaluates the feasibility of implementing a space sunshade in the vicinity of the first Lagrange point of the Sun-Earth system by the middle of the century. The analysis considers the necessary technological development, the possible trajectories for the shades, and an approximation of the size and cost of the system. It is strongly dependent on the possible optical properties of future solar sails, so an optimal and a more conservative alternative have been studied. With the latter, the shade will be formed by 1.5 × 109 sailcraft with a sail area of 2500 m2 and a total mass of 8.3 × 1010 kg. In the optimal case, the total mass is 3.4 × 1010 kg. Each one of these sails will be launched to a 2000 km orbit, from where they will travel for about 600 days to the equilibrium point using solar radiation pressure. The total cost of the mission is estimated to be five to ten trillion dollars, based on a launch cost of US$50/kg. There are two main technological challenges for this to become a reality: the low TRL of the solar sails proposed and the necessary development in the launch vehicle industry given the dimensions of the mission.

Characterizing Minimum-Time Solar Sail Geostationary Orbit Transfers Using Pseudospectral Optimal Control

This work examines the problem of planet-centered orbit transfers using solar sail propulsion. Though solar sails offer unlimited , they place coupled time-dependent restrictions on thrust magnitude and direction, and the multiple objectives of an orbit transfer can make locally optimal approaches inefficient; it is therefore advantageous to use optimal control to design such trajectories. This paper presents orbit-averaged equinoctial-element equations of motion for a solar sail under a discretized and interpolated control law. These equations are used to study transfer from a geostationary transfer orbit to geostationary orbit; a locally optimal control law is used to generate initial trajectories, and Gaussian pseudospectral optimal control is applied to yield minimum-time transfers. In the default case, with sail area–mass ratio of , optimization reduces the transfer time from 1222 to 293 days. Finally, sail area per mass, sail reflectivity, and initial sun–Earth orientation are varied to explore their effects, and to provide general design guidelines for planet-centered solar sail transfers. Distinct performance regimes are observed for transfers taking longer or shorter than one year, and for reflectivities greater or less than 0.4. Additionally, initial solar position was found to drastically affect the behavior of transfers in the fast regime.

Osmanlı Döneminde (1915-1918) Bandırma-İstanbul Deniz Ulaşımı ve Vapur Yolcu Listeleri

Bandirma, cografi konumu ve denizyoluyla Istanbul’a yakinligi nedeniyle ozellikle Osmanli Devleti’nin son doneminde buyuk onem kazanmistir. Bandirma-Istanbul denizyolu daha once de kullanilmakla birlikte modern donemde bu kullanim gittikce yogunlasan bir seyir izlemis ve bu durum Bandirma kenti ve limaninin daha islevsel hale gelmesini saglamistir. Basta gida maddeleri olmak uzere Istanbul’un cesitli ihtiyaclarinin karsilanmasi hususunda Bandirma’dan saglanan mallardaki artisa paralel olarak Bandirma-Istanbul arasi vapur seferlerinin yani sira yolcu sayisinda da artis kaydedilmistir. 19. yuzyilin sonlarina dogru Bandirma limaninin verilen hizmetler acisindan yetersiz kalmasi nedeniyle; iskelenin buyutulmesi, limandaki hizmet alanlarinin genisletilmesi ve gece seferlerindeki riski ortadan kaldirmak amaciyla belirli yerlere deniz fenerleri insa edilmesi gibi bazi insa ve imar faaliyetleri yapilmistir. Bu calisma, Bandirma-Istanbul denizyolunun Osmanli donemindeki onemine dikkat cekmeyi ve 1915-1918 yillari arasinda Bandirma’dan Istanbul’a sefer yapan vapurlara ait yolcu listelerini analiz etmeyi hedeflemektedir. Listelerin yer aldigi belgeler sayica az olmasina ve bir seri teskil etmemesine ragmen yolcularin kimlikleri, meslekleri, nereden geldikleri ve Istanbul’da nerede konaklayacaklari gibi bilgileri icermesi acisindan onem arz etmektedir. Makalede soz konusu bilgiler tasnif edilmis, mumkun oldugu olcude sayisal verilere donusturulmus ve 1915-1918 yillari arasinda Bandirma-Istanbul denizyolu guzergâhini kullanan yolcularla ilgili iktisadi ve sosyolojik bazi degerlendirmeler yapilmaya calisilmistir.

De las bóvedas nervadas al cañón con lunetos. Las iglesias de bóveda baída en el ámbito valenciano

<p>Los cambios arquitectónicos realizados desde el lenguaje gótico al clásico a partir de la irrupción del renacimiento, supuso la adopción de nuevos parámetros espaciales y compositivos que necesitaron del soporte de nuevos sistemas constructivos y geométricos. Es significativo el proceso evolutivo experimentado en los abovedamientos de las iglesias de la Corona de Aragón durante el recorrido que conduce desde las bóvedas nervadas propias del gótico hasta las bóvedas de cañón con lunetos barrocas. En el ámbito valenciano, y como un modelo intermedio entre los extremos del proceso, se realizaron unas pocas iglesias cubiertas con una sucesión de bóvedas baídas claramente adscribibles al lenguaje clásico. La solución geométrica de estas bóvedas basada en la esfera resultará clave.</p><span>En el texto se analizan cinco iglesias construidas con este sistema, y se muestran las soluciones adoptadas por los artífices para resolver cobertura de los diferentes templos con una geometría inédita hasta el momento.</span>

Sailing dinghy hydrodynamic resistance by experimental and numerical assessments

Hull forms of high-performance sailing dinghies are very interesting for yacht designers. After a long period in which the attention has been focused on one-design boats, in recent years a few exciting restricted classes such as International Moth, International 14′, 18’ Skiff and Class A catamaran become recognized in several countries and led to interesting advances in high-performance yacht design.“1001VELAcup R3” class is two people racing dinghy designed according to a box rule with limitation on LOA and Bmax and total sail area. The boats must be designed and built by students of European Universities and race yearly in Italy.This paper focuses on two best-ranked boats “LED” from the University of Palermo and “TryAgain” managed by the University of Naples but designed by the University of Roma3 team. These boats were definitely superior as regard motion resistance when tested without appendages during 2017 MIDWINTER INDOOR RACE and, although very different in main section shape, had comparable performances.The observed behaviours and the availability of experimental data suggested a suitable numerical approach and a fair comparison between experimental and numerical results is presented.

Sailing on an Ocean of Noble Causes: The Commonwealth Blue Charter

Sailing on an Ocean of Noble Causes: The Commonwealth Blue Charter

A Comparison of Yeats’s “Sailing to Byzantium” and Jibananda Das’s “Banalata Sen”

A Comparison of Yeats’s “Sailing to Byzantium” and Jibananda Das’s “Banalata Sen”

Riittääkö liberaali kansalaisuus?

Riittääkö liberaali kansalaisuus?
 Tässä kirjoituksessa käsitellään nykyeurooppalaisen suhdetta kansalaisuuteen poliittisen filosofian valossa. Kansalaisuuden kehitys on yleisesti tavattu jakaa klassiseen tasavaltalaiseen traditioon sekä moderniin liberaaliin traditioon. Kirjoitus käy läpi näiden olennaiset piirteet, ja asettaa kysymykseksi nykyisen eurooppalaisen mahdolliset näkökulmat omaan kansalaisuuteensa. Tässä kirjoitus ottaa lähtökohdakseen jo Aristoteleen esittämän vertauksen, jossa kansalaista kuvataan osana laivan miehistöä. Nykyisin niin eurooppalainen kuin kansallinenkin lainsäädäntö takaavat oikeudet ensi sijassa yksilöille liberaalin kansalaistradition hengessä. Mikäli tämän päivän Eurooppa tarvitsee kuitenkin tämän lisäksi suurempaa yhteenkuuluvuutta – kuin miehistöä yhteiseen laivaan – yksilön harteille jää kysymys siitä, onko hänen laivansa ensi sijassa kansallisvaltion vanha höyrylaiva, vaiko suuri Eurooppalainen risteilyalus.

Memories of Sail and Steam in Joseph Conrad’s ‘Youth’

本稿では，サールの虚構論および「社会的現実の構成」論を援用しつつ，ジョウゼフ・コンラッドの短編「青春」を，主に船舶技術の変遷という背景テーマとの関連から論じる。前半では，「青春」におけるジュディア号の創作上の航海を，本作のもととなった実際のパレスチナ号の航海と比較する。両者の相違および1880年代の船舶技術を検証する中で，帆船から蒸気船への海運における主役の交代が，「青春」における重要な背景テーマであることを論じる。 本稿の後半では，「青春」を多読教材（graded reader）化することの有用性を考察する。「青春」は『ロード・ジム』『闇の奥』とともに三部作をなす作品であり，本作におけるジュディア号の航海と，『ロード・ジム』におけるパトナ号の航海は，プロット上の役割に共通点がみられる。『ロード・ジム』と『闇の奥』はすでに多読教材化されており，「青春」がそれらを補完することになる。また本作は短編小説であるため，多読教材化にあたり会話の縮約が不要である上，「語りの間接性」や「遅延解読」といった，コンラッド三部作の主要要素を解説するページの付加も可能だろう。さらに「青春」における船員達の行動は当時の船舶技術の変遷を背景としているため，本作はその背景テーマを読み取るのに適した教材である。最後に，簡潔なプロットと印象的な情景描写により，本作は読み物教材としての魅力を十分に有している。

Sailing with Stevens

Sailing with Stevens

A Study on the Development of the Collision Prevention System for Aids to Navigation by Early Identification of the Tug Boat

Aid to navigation is a navigational aid facility that informs a sailing vessel of its location and direction as well as a location of a specific obstacle by means of a light, shape, color, sound, radio wave, etc. It can be valuable in improving the safety of day and night vessel navigation at sea. For the safety of the tug boat, the minimum equipment requirements for each type of tug boat are arranged. Despite these preparations, the collision accidents between tug boats, barges, and light buoys can occur when the tug boat turns due to the length of the tow-line, tidal current, and the barge’s momentum etc. The purpose of this study was to propose the basic system that analyzes the physical relationship between two vessels regarding the tug boat-barge-light buoy dynamics and propagate the corresponding data through the aid to navigation management & operation systems in use at each regional oceans and fisheries.

Introduction: Sailing along Intermedial Rivers

Introduction: Sailing along Intermedial Rivers

New Spaceship Sail Self-Centers

New Spaceship Sail Self-Centers