Propeller hydrodynamics can be complicated and messy, and sometimes the combination of propeller, vessel shape, gearbox, and engine are less than perfect. Age or lack of maintenance can also compromise performance – frequently causing an overload of the engine and a reduction in RPM. In such cases, it may be possible to relieve some of the problems and shift the operational RPM through a variety of propeller modification techniques, such as re-pitching by blade twist, diameter reduction, or even trailing-edge trimming and grinding. Join Adam Kaplan for this 30-minute webinar explaining the objectives, expectations, techniques, and limitations of propeller modification to achieve performance objectives. Is a new propeller needed to solve a performance problem? Maybe, but not always.
Thursday 29 April, 2021
This two part series on Hull-Propeller Interaction concludes with a session on Propeller Performance (Part 2). We discuss “wake-adapted” propeller design and analysis, as well as differences between steady and unsteady performance and calculation. Propeller design tips are introduced for operation in unsteady wake fields (including typical criteria for propeller blade-to-hull clearance), and we illustrate how estimates of Effective wake properties can be used when ship-specific values are not available. Join Don MacPherson for this 30-minute webinar that will introduce some of the key concepts about wake-adapted propeller performance that are needed by naval architects and designers to ensure best outcomes for noise & vibration, propeller efficiency, and overall performance.
Thursday 25 March, 2021
This two part series on Hull-Propeller Interaction complements our previous webinar on propeller-radiated noise with a focus on Wake Fields (Part 1) and Propeller Performance (Part 2). We discuss in Part 1 how velocities into the propeller are affected by the hull and are defined as a “wake field”. We further explain the various types of wake fields, break them down into useful “quality” parameters, and introduce recommended criteria for wake parameters and hull-propeller geometry. Join Don MacPherson for this 30-minute webinar that will introduce some of the key concepts about wake fields that are needed by naval architects and designers to ensure best outcomes for noise & vibration, propeller efficiency, and overall performance.
Thursday 4 March, 2021
The evaluation of Propeller Radiated Noise (PRN) has always been part of the assessment of internal noise, vibration, and habitability. In recent years, PRN has become a focal point for international regulatory efforts to reduce Underwater Radiated Noise (URN). While difficult to quantify analytically, there are ways to easily characterize PRN as well as common sense practices that can help designers reduce both internal and underwater PRN. This half hour webinar with Don MacPherson will introduce key principles of PRN, universal ways to reduce and mitigate PRN, and the hydroacoustic evaluation utility in NavCad that can be used to provide measures of influence for different mitigation strategies.
Thursday 11 February, 2021
Surface-piercing propellers (SPPs) have a very specific blade form, with cleaver shaped outlines, high pitch-to-diameter ratios, and carefully crafted wedge-shaped sections. As a result, successful surface-piercing propellers require the use of unique design elements. This webinar will cover the characteristics of SSP blade design and demonstrate how PropCad provides an extremely effective environment for SSP CAD modeling. Join Adam Kaplan in this half hour webinar to help you unlock the secrets of surface-piercing propeller design.
Thursday 28 January, 2021
Surface-piercing propellers (SPPs) are typically designed for high speed applications. Unlike conventional fully-submerged propellers, they encounter highly varying thrust-making regimes across the speed range. Understanding how each regime of SPP performance is influenced by speed, RPM, shaft angle, and propeller pitch is critical to successful SPP operation. This half hour webinar will introduce key principles of SPP performance, including NavCad’s new “cleaver-style” SPP propeller series as well as its prediction of the “critical transition”. Spend a few minutes with Don MacPherson to ensure best SPP outcomes for your clients and customers.
Thursday 14 January, 2021
While the primary objective of most sailing vessel designs is performance under sail, auxiliary propulsion is also an important consideration. Often, the heaviest non-structural components on a sailing vessel are the engine and its fuel. Since weight reduction is key to sailboat performance, accurately sizing the engine and fuel tanks are critical to meeting performance objectives both under sail and power. Join Alex Walker for this half-hour webinar to discover how HydroComp NavCad® can be used for quick, accurate performance prediction of auxiliary-powered sailboats to appropriately size the engine, fuel consumption, and even a folding propeller to meet your design goals.
Thursday 12 November, 2020
Tugs, trawlers, and other workboats require the ability to generate thrust for more than their own transit. They need supplemental thrust – known as “towpull” – to pull nets or push other boats. More than just “bollard pull”, towpull requires a properly functioning Vessel-Propulsor-Drive system. How does bollard pull differ from towpull? What design choices can ensure effective towpull? Join Don MacPherson for this half-hour webinar that will review how towpull is generated, its relation to bollard pull, and practices for propeller and driveline sizing.
Thursday 22 October, 2020
Tunnel thrusters are an invaluable asset for maneuvering and docking. But how do they really function? Did you know that inlet and discharge geometry can be as important as the thruster propeller itself for a successful installation? What about thruster noise? This half-hour webinar will introduce the hydrodynamic function of a tunnel thruster, as well as practices for sizing and design. Spend a few minutes with Don MacPherson to review the thrust-making capabilities of a tunnel thruster, techniques for inlet and tunnel design, and tips for the sizing and design of thruster propellers.
Thursday 25 June, 2020
Did you know that the pitch of a propeller can be modified? This process – half art form, half science – provides us some flexibility for correcting performance problems or even re-using propellers with different engines and gears after repowering.Join Adam Kaplan for this half hour webinar, where we will discuss how to identify a required pitch change, the practical limitations for repitching a propeller blade, and the physical geometric changes that occur during a propeller repitching. This webinar is appropriate for propeller repair shops, propulsion equipment vendors, naval architects, and boat builders.
Thursday 18 June, 2020
Vessel hull form drag is the principal system load that ultimately determines engine power, fuel consumption, and emissions, and we know that reducing this hydrodynamic “cost” is an important design objective. But is there a “best” hydrodynamic shape to achieve least drag? Probably. Can I use that shape? Probably not, since the other design objectives of hydrostatics and safety, structure and layout, even producibility and capital cost, typically have priority over considerations of speed and power. This half-hour webinar will review how “designer-guided hull form optimization” in NavCad helps point to the hull characteristics that offer drag reduction for a vessel design. Designers will then use this knowledge to optimize hull shapes that are compatible with their other design priorities. Spend a few minutes with Don MacPherson to review objectives, workflow, and a case study that used these techniques for substantial savings in fuel consumption and emissions.
Thursday 11 June, 2020