Jesse Spence - Academia.edu (original) (raw)

Papers by Jesse Spence

This paper summarizes the efforts undertaken by the author to identify existing and future potent... more This paper summarizes the efforts undertaken by the author to identify existing and future potential methods to reduce underwater sound levels created by nearly all oil and gas industry related activities, including sources associated with seismic exploration, construction, transport, drilling, and production. Information was collected from various sources including technical and trade journal articles, contacts with representatives of companies that

SNAME Maritime Convention, Sep 29, 2020

Awareness of underwater noise generated from shipping is rising due to environmental concerns in ... more Awareness of underwater noise generated from shipping is rising due to environmental concerns in sensitive areas with protected animal species as well as for the world’s oceans as a whole. Individuals interested in underwater noise have attempted to better understand the problem by performing measurements of vessel noise either by direct measurement or by recording sound levels in different oceans over time. These efforts provide insights into noise levels produced by vessels as well as the noise levels produced by shipping in different locations. However, in order to reduce underwater noise the specific causes of noise must first be identified. Various generalities of primary noise sources and radiation mechanisms can be given for different ship types, though in order to actually reduce noise the structural and machinery details of each ship must be known and considered as part of an acoustical design (or re-design) effort. Specific noise control treatments can be optimized to diff...

Marine Technology, Jul 1, 2012

Day 1 Wed, September 27, 2023

A ship is a complex system that utilizes multiple mechanical, electrical, and hydraulic systems d... more A ship is a complex system that utilizes multiple mechanical, electrical, and hydraulic systems during its operation. All these systems can generate noise and vibration, which if not properly addressed during design and construction may cause passenger and crew discomfort, safety issues related to degradation in voice communications, and even structural damage. The noise and vibration generated by a ship is a direct reflection of the quality of the design and construction of the vessel; lower noise and vibration environments will improve passenger experiences, improve quality of life and retention of the crew, and increase mission effectiveness. However, a vessel’s noise and vibration do not need to be left to chance. Engineering tools and processes can be used throughout the vessel’s design and construction which will produce a vessel with low noise and vibration. This paper presents a case study of the three new Staten Island OLLIS Class Ferries built by Eastern Shipbuilding Group...

OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information), Aug 1, 2019

Day 2 Wed, September 28, 2022

Underwater noise is a growing concern for commercial vessels. As an example, efforts are already ... more Underwater noise is a growing concern for commercial vessels. As an example, efforts are already underway to reduce underwater noise and related impacts to Southern Resident Killer Whales (Orcas) in the Pacific Northwest. Groups like Transport Canada, Maritime Blue, Port of Vancouver, and others are investigating appropriate noise limits for vessels and strategies for ensuring noise levels are reduced. With this, there is a strong desire to identify treatments that can reduce underwater noise on existing vessels. Numerous “menu-style” lists of potential treatments have been compiled, but deciding which treatment to use is not trivial. Underwater noise reductions generally cannot be achieved through selection of a single treatment from a catalog. Rather than selecting treatments from a list, stakeholders should look to reduce underwater noise by choosing the right design approach. This approach would ideally be applied during design and construction phases, though post-construction d...

Day 1 Tue, September 27, 2022

The capability to continually perform operations in ice is a function of multiple design factors.... more The capability to continually perform operations in ice is a function of multiple design factors. These factors may directly influence one another and are integral to the design spiral. The compromises made in vessel design directly impact the vessel’s noise and vibration characteristics. Unlike conventional ships, icebreakers are subject to additional dynamic loads arising from interaction with ice. Because icebreaker hull forms are generally influenced by unique performance requirements, engineering past experiences, production feasibility, and risk mitigation during operation, early design development to optimize both ship arrangement and machinery system parameters is necessary to avoid vibration problems. Numerical modeling techniques like the finite element method are indispensable when evaluating the low frequency vibration of a vessel during the design stage. Methodologies for estimating the dynamic loads associated with common shipboard excitations such as unsteady propelle...

Day 1 Wed, October 22, 2014, 2014

Marine insulation and joiner facing out fittings are known to affect the acoustical properties of... more Marine insulation and joiner facing out fittings are known to affect the acoustical properties of the surface they cover. Measured results provided in this paper show that these treatments can also have a substantial effect on the vibration response of ship structures at low frequencies (below 100 Hz). The accuracy of finite element models of marine vibration response to machinery and propeller sources can be improved by accounting for these effects. Two objectives are discussed in this paper: 1) quantifying the effect of various insulation and joiner treatments on the vibration response of a typical ship bulkhead based on measured data and 2) developing an efficient and accurate method to integrate these effects into finite element models for the prediction of vibrations on ships and marine structures.

IEEE Journal of Oceanic Engineering, 2017

Awareness of underwater noise from shipping has grown significantly within the marine community o... more Awareness of underwater noise from shipping has grown significantly within the marine community over the past decade. Concerns have been raised about the levels of anthropogenic noise in the world's oceans, as well as in harbors and areas with sensitive or protected marine life. Regulatory bodies are listening, and are considering what actions are available to reduce noise. Measurements of vessel noise in various situations have been performed to better quantify the problem, and efforts have been made by some to correlate noise levels with simplified vessel parameters. Such efforts provide insights into what levels of noise are possible and how they are related to ship operation. However, to reduce underwater noise, a deeper understanding of specific vessel design and factors that lead to noise are required. While generalities of primary noise sources can be applied to different classes of vessels, design details of specific vessels must be obtained and analyzed to implement noise reductions. Armed with knowledge of vessel details, noise control strategies can be optimized using various computer-aided tools. This must be done on a case-by-case basis for different vessel designs, and is most efficient and effective for new builds. Costs for such efforts must also be considered if vessel noise is to be made inherently quieter worldwide.

Hearing Research, 2017

The US Navy, through an Office of Naval Research (ONR) lead effort on Noise Induced Hearing Loss ... more The US Navy, through an Office of Naval Research (ONR) lead effort on Noise Induced Hearing Loss (NIHL), is investigating methods and techniques to mitigate hearing loss for the crews and warfighters. Hearing protection is a viable and increasingly popular method of reducing hearing exposure for many ship crewmembers; however, it has limitations on comfort and low frequency effectiveness. Furthermore, Personal Hearing Protection (PHP) is often used improperly. Proper vessel planning, programmatic changes and advances in noise control engineering can also have significant impacts by inherently reducing noise exposure through ship design and use of noise control treatments. These impacts go beyond hearing loss mitigation since they can improve quality of life onboard vessels and provide enhanced warfighter performance. Such approaches also can be made to work in the lower frequency range where hearing protection is not as effective. This paper describes non-hearing protection methods being implemented to mitigate and control noise within the US Navy and US Marine Corps. These approaches reflect the latest changes to Mil-Std 1474E, Appendix F.

Offshore, 2009

The impact of seismic exploration on marine life is becoming an ever more prevalent consideration... more The impact of seismic exploration on marine life is becoming an ever more prevalent consideration for the offshore oil and gas industry. Discussion continues on exactly how much sound is acceptable, but owners and operators today increasingly must comply with regulatory agency rules.

Proceedings of Meetings on Acoustics, 2012

This paper presents a review of two projects undertaken to design underwater acoustic barriers. W... more This paper presents a review of two projects undertaken to design underwater acoustic barriers. While these barriers can be used to control noise from many sources the most immediate application would be to reduce noise from piles for bridge construction and repair and offshore wind turbine installations. The design considerations required during the development of underwater barriers are reviewed, including acoustical and structural design considerations, computer modeling of system performance, and realities of on-site deployment. Barrier performance data from the field or testing facility are also presented, along with observations from years of development and deployment in regards to "next steps" and suggested research paths for further investigation.

Proceedings of Meetings on Acoustics, 2010

Finite Element Methods (FEA) have become part of the standard repertoire when designing a ship. T... more Finite Element Methods (FEA) have become part of the standard repertoire when designing a ship. This is particularly true for static analyses, though FEA methods are becoming increasingly utilized for analysis of low frequency vibration as well. This paper discusses the FEA modeling process that was used for analyzing low frequency (<80 Hz) 'habitability vibration' on a 255' vehicle ferry. Deck vibration levels were measured after the vessel was built. Measured vs. predicted vibration data show good correlation, particularly when the various sources of potential error and uncertainty are considered. The subject ferry was designed to meet the ABS Comfort Class "COMF" vibration criteria. Calculations of deck vibration were performed using NEiNastran to verify compliance with the criteria. Excitations due to propeller hull pressure excitation are highlighted here as these forces created the largest deck responses. However, it is noted that the main propulsion engines were resiliently mounted subsequent to initial analyses using the FE model. This paper discusses pertinent details of the model (element types, properties, etc.), application of hull pressures, damping, analysis methodology, and interpretation of results. Areas of uncertainty and impacts to the results are discussed.

For many years naval architects have had access to software covering specific aspects of ship des... more For many years naval architects have had access to software covering specific aspects of ship design, such as hull form design, stability calculations, structural analysis, and speed/power prediction. By their nature, each design tool has its own method of modeling the ship. Similarly, there are various and diverse tools for acoustic design – considering habitability noise, habitability vibration, underwater radiated noise signature, sonar self-noise, target strength, or shock response. Yet all of these acoustic models have one item in common - the hull structure. Thus, one common tool set should be able to utilize this base hull structure to minimize the total effort needed to effectively address acoustic characteristics of naval vessels. Presently, Statistical Energy Analysis tools can accurately predict habitability noise, underwater radiated noise, and sonar self-noise. Boundary Element Methods can be used for target strength and Finite Element Codes for habitability vibration a...

Underwater noise produced by vessels and platforms can impact mission goals and marine life. For ... more Underwater noise produced by vessels and platforms can impact mission goals and marine life. For example, excessive noise produced by fisheries research vessels may alert fish and other aquatic animals to the ship’s presence, thereby affecting stock assessments and research objectives. Similarly, vessels relying on underwater acoustic communications systems, sonar operations, and other forms of acoustic exploration require noise from the vessel to not interfere with operations. Vessels and platforms operating in environmentally sensitive areas may also require lower levels of underwater noise to meet desired or imposed criteria; requirements for limiting underwater noise radiation are being applied to new vessel and platform constructions by owners. Regulatory bodies such as the International Maritime Organization and others are also considering regulations on underwater noise for shipping, at a minimum, to combat the rise in noise levels in the world’s oceans. A highly portable und...