Narrow Results

Faced with environmental and economic challenges, the transition to renewable energies is a priority, particularly in the maritime transport sector, which is subject to increasingly strict regulations. For ships, this adaptation remains complex due to space constraints and the rapid pace of technological advances, sometimes making certain solutions quickly obsolete and generating losses for shipowners. This work explores the use of rotating cylinders, based on the Magnus effect, as an auxiliary propulsion solution for ships. This effect occurs when air circulating around a rotating object creates a pressure difference, generating a force perpendicular to the airflow and the cylinder’s axis of rotation. Compared to other wind technologies, this method has promising potential to reduce emissions and improve energy efficiency. The results of this study highlight the economic and environmental benefits of rotating cylinders, positioning them as a clean and renewable energy for ship propulsion. These findings, consistent with previous work, highlight the rationale of this technology, already adopted by some modern commercial vessels, such as bulk carriers, oil tankers and cruise ships, which seek to optimize their energy efficiency. Thus, despite the challenges, the benefits related to fuel savings and reduced emissions make Flettner cylinders a promising solution for the future of maritime transport.

In this brief article, I present the surprising, symmetry-breaking behavior of a homogeneous log of maple wood. The log is of square cross-section, and is placed to float in a tank of water. The straight symmetric floating state turns out to be unstable, and it immediately lolls over to an unexpected angle. This could explain why, when I was a young kid, my carefully made boats often did not float upright.

Cruising for leisure purposes, whether on the ocean, along coasts or rivers, has demonstrated consistent growth as a tourism activity. Cruising can be divided into a number of sub-markets, within which most supply is oligopolistic in nature, and concentration is increasing. Cruise lines pursue various strategies, but it is shown that pricing is not the most significant, as demand, cruise products and prices are amorphous. Unlike fixed-location tourism, cruising is a footloose product, where factor inputs may be sourced globally and cruise lines may have little connection with port destinations served on itineraries. Operationally, economies of scale, capacity and revenue management are important tools for operators, as vessel sizes increase and operational management and marketing become more sophisticated. The impacts on local and national economies are in many ways analogous to those of tourism in general.