Various sensing and digital signal processing approaches to detect cavitation in a water jet propulsion unit were examined based on results in the literature. Several commercially viable sensors were evaluated based upon their ability to detect the cavitation phenomenon, cost, and robustness. An algorithm has been implemented and tested against data recorded from the candidate sensors. The combination of vibration and pressure sensors and the algorithm appear promising and a path for further development and testing is available to Hamilton Jet.

There is a boat burial in Scar, on Sanday, Orkney that was excavated in 1991. This undergraduate thesis compares Scar with 5 other boat burials from Norway, to determine if the burial custom is uniform or if there are regional differences.  The 6 burials are presented individually and then the type and typology of the finds is compared. The conclusion is that the boat itself and the rivets in the boat burial in Scar are very similar to the burials in Norway, and there are strong similarities between the finds in Scar and the corresponding type of finds in the Norwegian burials. However, they are not uniform in their collections of finds, and this could be due to regional differences. Other potential causes, such as dating of the burials, are discussed as well.

Geophysical methods are non-invasive and allow an effective way of understanding subsurface structures and their physical properties. One of the main challenges is the often non-uniqueness of the geophysical models and that several different models can explain a dataset to an agreeable fit. Moreover, noise and limitations in resolution, which are inherent to field data, are additional obstacles for obtaining a true physical property model of the subsurface. Facing all these challenges, geophysicists have dedicated their efforts for decades to recover models that represent, as close as possible, the true subsurface. Joint inversion and integration of multiple geophysical data are two main approaches that I studied to better resolve subsurface structures. I further used these approaches, together with new software and hardware implementations for data acquisition and inversion, for near-surface applications.  In this thesis, radio-magnetotelluric (RMT), boat-towed RMT, boat-towed controlled source MT (CSMT), electrical resistivity tomography (ERT), and first-arrival traveltime tomography are jointly used for quick clay investigations and fracture zone delineation under shallow water-bodies. The joint approach, as compared with any individual method, shows a better ability to both resolve the geological targets and to assist in understanding the subsurface geology that hosts these targets. For examples: by performing the joint inversion of lake-floor ERT and boat-towed RMT data, a fracture zone is better delineated with greater details compared with single inversion; by employing boat-towed CSMT measurements and jointly inverting with boat-towed RMT data, the subsurface structures, especially at greater depth, are better resolved than by inverting each dataset alone. During my PhD studies, two types of new implementations were employed. (1) Boat-towed data acquisition system was implemented to expand the RMT and CSMT method from land to shallow-water applications. This is significant since many large-scale underground infrastructures are likely to cross these water zones (for example multi-lane train or bypass tunnels, such as the Stockholm bypass). (2) The modification of a well-structured code EMILIA allows joint inversion of boat-towed RMT and lake-floor ERT datasets, and the modification of another well-structured code MARE2DEM can accurately model high frequency CSMT data and handle joint inversion of boat-towed RMT and boat-towed CSMT datasets. Thus, the code modification as another type of new implementation guarantees the success of near-surface applications using the boat-towed RMT and CSMT data acquisition systems. Studies conducted during my PhD work, included under the SEG-GWB (the Society of Exploration Geophysicists - Geoscientists Without Borders) program and the TRUST (TRansparent Underground STructure) umbrella project, are useful for near-surface applications including, for examples, engineering purposes such as planning of underground infrastructures, site characterization in connection with energy or waste storage, and geohazard investigations.

Boats have a rich history, evolving in shape and purpose. From ancient logboats to modern superyachts, their design depends on their intended use. Among personal watercraft, such as yachts and motorboats, there are various types like fishing boats and day cruisers. Runabout boats are popular today for leisure. They are fast, agile, and versatile, originating in the 1920s with wooden bodies. Modern Runabout boats carry 4-8 people, lack a cabin, and are favored by casual boaters.  One of the latest trends within boating is the usage of hydrofoils, a hydrofoil is a wing-like shape that lifts a boat out of the water, reducing drag on the boat. Flighter is a new company intending on creating a new concept for a hydro foiling boat that is meant for transportation. They want a boat that is agile and has some multifunctional aspects allowing it to be used by a wider user group.  The following project is a design project focused on the conceptual interior design of Flighters new boat where the goal is to create an interior that fits with Flighters agenda. The concept developed through the project uses a rail system to create modular seating that allows the user to modify the boat to the current needs. There is also a multifunctional sofa in the back allowing for extra storage and seating if needed.

There have long been concerns about the negative impacts of recreational boating activity in the Indian River Lagoon system (IRL), especially in Mosquito Lagoon (ML), the northernmost part of the IRL. My research is focused on the impacts of boat wakes on intertidal reefs formed by the eastern oyster, Crassostrea virginica. There has been a 24% loss of oyster habitat in ML since 1943, where natural oyster reefs have been replaced by dead oyster reefs which do not serve the same ecological function. While there is anecdotal and correlative evidence that this loss is a result of boat wakes, no studies to date have confirmed dead reefs can be a direct result of boat wakes. Therefore, I addressed the following questions: (1) What wake heights are generated by a range of boat types, and (2) What amount of oyster movement and erosion occurs as a result of these boat wakes? A series of boat pass experiments addressed the first question; these results were utilized in experiments at Florida Institute of Technology's wave tank to observe sediment erosion and oyster movement as a result of specific wake heights. Model selection was used for both the field and wave tank experiments to determine which variables contributed most to explaining the wake heights, erosion, and oyster movement that occurred. Wake heights ranging from 0.05 cm to 20.80 cm were documented contacting the oyster reefs from the boat passes, with a mean of 2.95 cm. Boat type was less important than speed or distance when determining wake height. My wave tank results document that wake heights as small as 2 cm contacting oysters are capable of moving individual and clusters of oysters. Minimum distances for boats to travel in order to maintain wakes smaller than 2 cm at reefs are suggested for management purposes based on regression equations. This could minimize the amount of movement that occurs when oysters are subjected to boat wakes. The results of this study can help resource managers implement boating policies in Mosquito Lagoon, and contribute greatly to conserving this important ecosystem engineer.

No description available.

<p> In this dissertation the author provides an analysis of three separate but interrelated aspects of the experiences of women who have been treated for breast cancer and who participate in survivor dragon boat racing.</p> <p> In the first analysis the author addresses the multiple meanings and functions that this physically intense competitive team sport has for the women. The paper explores some of the reasons why this activity appealed to them and the kinds of impacts and effects that participation in this activity had on their lives. The second analysis offers a critical look at the ways in which breast amputation has been characterised within the medical and breast cancer literature as a threat to women's self identity as female or feminine. The data from this study however demonstrates that women's experiences of breast amputation is much more complex and nuanced than characterised. Also included is an examination of women's own perspectives on this experience, as well as the mediating role that dragon boat racing had on this aspect of self identity. The third analysis focusses on a major theme that emerged from the data which was the transformative effect that competitive dragon boat racing had on women's bodies and on their sense of self. Discussed here are the impacts and effects that participation in competitive dragon boat racing had on women's self identities and bodies and that enabled the women to see themselves as strong, fitter, healthier and "better" than what they were prior to their breast cancer illness experience. Finally, the author concludes with a discussion of how regular participation sport, and especially for women living with a critical illness, can empower women at the individual, group and societal levels.</p> / Thesis / Doctor of Philosophy (PhD)

Wave energy is a major driver for many coastal processes and influences wetland vegetation and shoreline stability. Coastal conservation and restoration projects often include wave climate estimations in the decision-making process for project design. The current method primarily used to estimate a project area's wave climate is the use of wind-wave models. These models use wind speed, wind direction, bathymetry, and fetch to estimate site-specific wave activity. However, these models neglect boat wake which is an important contributor to wave energy in fetch-limited environments. This study used site-specific wave measurements to compare wind-protected and open sites in Back Bay, Mississippi. Study results demonstrated that some protected sites experienced similar or even higher wave activity when compared to the open sites. These findings indicate that excluding boat activity from wave climate estimations could lead to an under-estimation of site-specific wave activity.

The Swedish Sea Rescue Society (SSRS) is a non-profit organisation which performs themajority of rescue missions on Swedish waters. SSRS together with many other companies arecurrently under development of a novel boat design which is battery powered. This leads to aspecific challenge of shorter available reach compared to the traditional diesel engine poweredboats. The solutions is to make use of hydrofoils which enables the potential for the hull to belifted above sea level and reduce drag resistance by up to 80% The purpose of the project was to through a broad background study, develop systems that allowretraction and extension of the hydrofoil from the hull of the boat. After generating 10 concepts,these were evaluated by performing an elimination- and decision matrix. Two concepts werechosen to be further developed. The two concepts were in many aspects similar in regards tocomponents and the outline of them except one was actuated by a multi-stage hydraulic cylinderand the other by a servo motor and roller screw. Analytical calculations, choice- anddimensioning of components and FE-analysis in NX Nastran were done in the furtherdevelopment-stage. It was found that both solutions were viable options to integrate as hydrofoil extension andretraction mechanisms on an electric boat. After completion and interpretation of the results itwas concluded that an electromechanical solution would be prefered to use as the underlyingtechnology for the lifting mechanism. / Svenska sjöräddningssällskapet (SSRS) är en ideell organisation som utför majoriteten avräddningsuppdrag i Sverige. SSRS tillsammans med flera andra företag är under utveckling aven ny båtdesign som ska drivas av el, vilket leder till en specifik utmaning i form av en kortaretillgänglig körsträcka gentemot den traditionellt drivna motorbåten. Lösningen är att använda sigutav s.k. bärplan, vilket möjliggör skrovet på båten att lyftas över vattenytan och reducerarfriktionskrafterna med upp till 80%. Projektet gick ut på att genom en bred bakgrundsstudie utveckla koncept av system som tillåterin- och utfällning av detta bärplan från båtens skrov. Efter en generering av 10 varierandekoncept sållades dessa ut genom en eliminerings- samt beslutsmatris. Två av dessa konceptvaldes att utveckla vidare. Dessa två koncept var i många hänseenden identiska i utformning avkomponenter med skillnaden att den ena var driven av en teleskopisk, 2-stegs, dubbelagerandehydraulcylinder och den andra med en servomotor och rullskruv för att utföra linjär rörelse.Analytiska beräkningar, urval och dimensionering av komponenter samt FE-analyser i NXNastran gjordes i vidareutvecklingen av koncepten. Båda koncepten visade sig vara lämpliga alternativ i tillämpningen som mekanism till ett ut- ochinfällbart bärplanssystem på en eldriven båt. Efter slutsats och tolkning av resultatet framgick detatt den elektromekaniska lösningen nog skulle vara den mest lämpliga teknologin bakomlyftmekanismen.

No / Boat people, whether refugees or migrants, are protected by special provisions in custom and law relating to safety and rescue at sea. At the same time, the governments of coastal states have expressed concern about the arrival of boat people and have been robust in depicting and treating them as a threat. The questions addressed in this article are: how and why have boat people been regarded as a threat, and what challenges does this treatment present for the humanitarian regime at sea? The article connects two dimensions of the issue. First it deconstructs the prevailing images and discourse surrounding boat people that contribute to securitizing them as a threat. Securitization is defined as the process by which issues are identified, labelled and reified as threats to a community, often by politicians for electoral gain. Second, the article argues that this securitization challenges the maritime regime, which is infused with humanitarian values based on solidarity among seafarers. Both short and long-term remedies might be considered. The immediate requirement is to ensure not only that asylum seekers at sea continue to be rescued and protected but also that the maritime regime is strengthened to facilitate their arrival at a place of safety. Over the longer term, de-securitizing the issue of asylum seekers and boat people requires action to address perceptions in destination states.