After ringing in the New Year, we'd like to reflect on the many advancements accomplished in 2023. With several new features available in this latest version of TrueProp, we also introduced new products that can be used with our software, were featured in published articles, attended industry events, and started our Scan Showcase.
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We had a fantastic time at NMPA's Annual Marine Propulsion Expo in Fort Lauderdale! It was great reconnecting with old friends, making new ones, and sharing the latest innovative developments in TrueProp. It was an eventful trip complete with networking, presenting, and exhibiting. Chief Technical Officer, Adam Kaplan, introduced our new 3D Scanning Bundle (which includes the Einscan 3D Scanner), as well as our first entry-level pitchometer, HELIX! Plus, we had the pleasure of visiting Frank & Jimmie's Propeller in Fort Lauderdale and seeing how they have been successfully utilizing TrueProp Virtual. Many thanks to Frank & Jimmie's for hosting! We are extremely proud to now offer this entry-level pitchometer, making a crucial tool for propeller inspection and repair more accessible to businesses of all budgets.
New Hampshire-based TrueProp was formed in 2017 as an offshoot of HydroComp. Since then, the company’s specialist propeller inspection and repair software has been widely used within the industry. This software has recently been upgraded to meet the evolving requirements of shipyards and other propeller service providers, and now offers a virtual plug-in for 3D scanners. The TrueProp core product based on inspection and repair codes with a diagnostic screen, remains the same. However, a new parallel code, that enables the software to integrate with a 3D scanner, has been introduced. The TrueProp Virtual Plug-in allows the user to extract angle-drop data automatically. This data is then analysed for class compliance with TrueProp. This development means there is no longer a need to remove the propeller from the ship, which significantly saves on costs and time for yards. “Our aim is to allow shipyards and drydocks to inspect the propeller without the need for a specialist workshop. The link between our software and the 3D scanner means that yards can inspect even large and complex propellers, including CPP units, with a simple handheld device,” says Adam Kaplan, chief technical officer. “As a result of this initiative, yards can save a lot of time and money as it is possible to scan the propeller without dismantling and transporting it away from the ship, and to assess if a repair is needed, and if so what type of repair is required, in situ. Consequently, the whole drydocking schedule can be significantly accelerated," adds Kaplan. According to Kaplan, the new 3D Virtual Plug-in will allow TrueProp to target an expanded market base.“ Whereas previously customers used to have to have specialist machines, and dedicated propeller repair and service workshops, that is no longer the case. This upgrade enables our customer base to be expanded and thereby make the servicing and repair of propeller units more widely available,” he says. 3D scanners are largely general-purpose tools and can be used for a variety of other tasks within a yard, for example in connection with the routing of piping. So, any investment in the device can be quickly paid off. Furthermore, the TrueProp 3D Virtual Plug-in can be used with a variety of commercially available scanners. However, the company offers a hardware and software bundle that includes TrueProp Virtual and the Einscan HX from Shining 3D. This bundle allows propellers as large as 3m (120inches) to be scanned with a portable hand-held scanner. The user can enter the diameter and select the radial positions for extracting ISO 484 type data, with a process that mimics the traditional pitchometer process, etching scan lines into the captured propeller in 3D.
The TrueProp Virtual Einscan HX bundle provides fast 3D capture from 14 simultaneous blue light laser lines and its stereolithography (STL) 3D file output is considered perfect for analysis with the TrueProp Virtual edition. “Using the TrueProp Virtual Plug-in, even non-watertight STL meshes can be interrogated at the ISO 484 radial positions. This provides us with the pitch, chord lengths, blade outline and other metrics used in TrueProp’s Class reports,” says Kaplan. TrueProp Virtual is currently being utilized by more than 30 propeller shops worldwide. The company also reports a significant amount of interest amongst larger shipyards which have traditionally outsourced both propeller inspection and repair. “We are seeing more shipyard interest and at a recent ship repair conference in New Orleans my presentation on the subject attracted a full room! I think that shows that the concept is resonating positively amongst yard operators as well as other propeller service providers," notes Kaplan. Earlier this year TrueProp 2023 was released as the latest version of the propeller inspection software. The new features include expanded diagnostics to identify and correct damage to propellers, including evaluation of propeller blade thickness, blade areas and effective pitch. Operators can quickly determine what is wrong with a propeller and take corrective action, if necessary, the company states. With the 2023 version TrueProp has also introduced a new upgrade and support programme. This is claimed to provide much needed support for the propeller service industry, reducing downtime for propeller inspection devices and ensuring that technical questions are answered promptly by other knowledgeable professionals. *This article was originally published in the July/August 2023 edition of Professional BoatBuilder Magazine, written by Dieter Loibner.
That changed with the advent of personal computers, special software, and electronic measuring devices like wands and scanners that produce and transfer digital data. It’s still a job for skilled technicians, but their tools have evolved. A screenshot shows the condition of a high-performance seven-blade propeller. The measurements for each blade have a specific color and here are close to each other and within the Class S tolerance. A high-pitch five-blade prop shows in a similar display. During the 1990s, several providers of computerized propeller measuring devices entered this limited and specialized market. Only a few survived. “We were asked over and over to develop something for these old machines from the nineties, because the original equipment vendors went out of business,” said Adam Kaplan, CTO of TrueProp in Newmarket, New Hampshire. The firm is a spinoff from HydroComp, Inc., which develops and markets design tools for hydrodynamics and propulsion systems, including software for propeller design, sizing, and manufacturing. “People were using [these machines] but couldn’t get parts or support, [and] were running old Windows 95 computers with all this stuff.” Kaplan said HydroComp initially was contracted for the electronics integration and software development for a new scanning tool, a one-off project that morphed into the TrueProp software, which is part of an integrated solution. A typical use of TrueProp is tracing the surface of a defective propeller with a scanner to measure blade height and angle. The program provides visual aids in the form of charts and diagrams that illustrate the tolerance (i.e., the acceptable difference between measurements), so technicians recognize what alterations are necessary to bring a damaged prop back into shape. “Some repairs are outside the limits of what’s possible to do by moving the metal, so sometimes you need to replace things, and, in that case, the software also helps [technicians] measure and determine what they have,” Kaplan said. “There’s another aspect—performance tweaking. If you have an engine problem or speed problem with the boat, [propeller shops] can use TrueProp to make some modifications to the propeller.” Kaplan observed that propeller designs “are becoming much more advanced and thus much harder to repair with traditional tools.” To keep pace with this evolution and the changing repair and service requirements for newer prop styles, TrueProp partners with Creaform of Lévis, Quebec, Canada, a manufacturer of portable 3D measuring equipment, and Linden Propeller of Dubuque, Iowa, makers of the hydraulic Prop Press and the Digital Data Scanner—all compatible with the TrueProp software. “We were an early adopter of the software but use it differently than other shops,” said Jody Bell, vice president of sales at Osborne Propellers in Langley, British Columbia, Canada, which serves workboat and leisure craft markets. “We use TrueProp more for the capture of current propeller geometry to feed into our CAD system than for repairs. We design and build propellers for commercial applications, and TrueProp is quite handy in capturing geometry that would otherwise be very hard to measure, specifically rake and skew distribution and chord lengths.” Bell said Osborne runs three different Hale MRI machines for propellers ranging in size from 50“ to 120“ (1.27m to 3.05m) diameter. Bell commended TrueProp’s ability to customize the software to improve compatibility and workflow when using existing equipment, something he felt had been missing with other vendors in the past. “TrueProp is affiliated with HydroComp, and we use their other software packages, and they talk to one another nicely. We are able to capture design features that allow us to replicate propeller geometry quickly and easily using our existing measuring equipment.” The digital revolution made it a lot cheaper and faster to produce and share data with others in the supply chain. Osborne also relies on HydroComp’s PropCAD to produce drawings and coordinate tables for manufacturing custom propellers, and for its built-in features to calculate thicknesses and provide torsional data to engine and gear suppliers. Asked about sending workers to shipyards to inspect and repair propellers, Bell said he prefers to work in-house, where his technicians can get better results faster than off-site. “The cost of insurance is also a factor. Adding ship repairers’ liability insurance is a huge expense, so we choose not to. I’m certain that this costs us some jobs every year, but we’re better off in the long run.” Osborne does not cast propellers and often chooses between machining in-house or through subcontractors as needed. Contracting out certain types of work, Bell explained, “allows us to scale up our capabilities without the capital expense.” In some cases, heat is still applied to shape damaged propellers. For nearly 30 years, Cool Breeze Marine of Osage Beach, Missouri, has been fixing props on the shores of the Lake of the Ozarks. Customers include local boaters with prop trouble, but the shop also works on specimens sent from other parts of the country, not just by recreational boaters but also by racers. “Manual pitch blocks, rake gauges, a good eye, and 30 years of knowledge” is what shop owner George Peter used before switching to the TrueProp software and PropExpert, a program to calculate diameter, pitch, reduction-gear ratio, and blade area when sizing propellers. Peter’s shop, which is certified by the National Marine Propeller Association sees a diverse range of defective propellers, from trolling motors to trawlers, and from aluminum runabout props to 6-blade high-performance stainless-steel to 8-blade 40“-diameter (1m) inboard yacht propellers. “People hit rocks, logs, their own boat trailers, or dock lifts and cables,” he said. “In the rainy season, it’s mostly logs. In the dry season, it’s mostly rocks. Damage happens all year long.” Peter calls TrueProp “the most accurate system on the market today” because it eliminates guesswork. He uses a Linden Digital Data Scanner with the TrueProp software to analyze the propellers and Linden’s hydraulic Prop Press 360 to bend them back into shape. Not every customer checks in with prop trauma. Many ask for a propeller tune-up to improve performance. “Where the Prop Press 360 and TrueProp software really come into play is when we are doing performance modifications,” Peter said. “We can take existing specs and data off the prop, talk with the customer to see what they want their boat to do or any performance issues they’ve encountered, and we figure out what it’s going to take to change the props to make that happen. Bending the prop accordingly can save customers time and thousands of dollars, and it gives them better fuel economy and longer engine life, because the prop will be modified to help the boat perform the way it should.” A technician at Osborne Propellers in Langley, British Columbia, Canada, balances a large four-blade prop. When it comes to bent props, there are different levels of mystery, Peter intimated. If the extent of the damage is visible, the evaluation by experienced technicians is usually quick and straightforward. When a customer tells him, “We didn’t hit anything, but now the boat shakes,” the only way to see it is with a scan that shows where the bend is and where to fix it. Smaller props are put on pitch blocks and beat into shape with rawhide-faced hammers, while large propellers are put on the Prop Press to be scanned and subsequently bent back with hydraulic force until they conform to specifications. If necessary, missing metal is welded back on, followed by grinding, finishing, and balancing. “Turnaround time depends on the level of damage and the time of year the prop comes into our shop,” Peter said. “It can take anywhere from one to two days to three weeks, [but] average is about two weeks.”
As a complication, propellers continue to evolve. “Back in the day, we talked about pitch, like a propeller can be a 20“ [0.5m] pitch,” Kaplan mused. “And traditionally those 20“ props measured that same value everywhere across the prop. But designs have advanced so much now [with] a lot more curvature and variation from the leading to the trailing edge of the blade, and from the root of the blade up to the tip. So you really need a digital system that allows you to compare these blades in a meaningful way. Traditional tools don’t quite work with these newer propeller designs. People can’t just repair them like they used to. They can’t use their grandfather’s methods.” More examples of propeller repairs can be found on TrueProp’s showcase page TrueProp, 5 Penstock Way, Suite 101, Newmarket, NH 03857, USA, tel. 603–868–3366. Introducing TrueProp 2023, the latest version of our next-generation propeller inspection software! Building off our progress in 2022, the latest update includes a number of great new features for our users. Major new features released in 2023 include:
With the 2023 version, we’ve also introduced our Upgrade and Support program, allowing you to upgrade your program version and get a tailored level of support to fit your business. Having access to the most robust features and personalized customer support maximizes the value of your software and ensures no interruption in receiving updates and technical support. Isn’t it time you added TrueProp to your shop? Contact us today to get started! Figure 1 – TrueProp Virtual now supports maximum thickness extraction from full 3D CAD models. Figure 2 – New features allow users to click/drag tolerance boxes for precision tuning of pitch progressions and pitch spans. Figure 3– Interactive graphs allow pan and zoom so you can see your repairs in detail. Figure 4 – TrueProp 2023 includes improved estimates for Blade Area Ratio.
After ringing in the New Year, we'd like to reflect on the many advancements accomplished in 2022. With several new features available in this latest version of TrueProp, we also introduced our Upgrade and Support program, with tiered levels of support to ensure the right fit for your business! Plus, we've had a blast with our Instagram Live series that we started at the beginning of this year - it's been a great way to connect with shops and see the software in action! Major new features for the 2022 release include:
Figure 1 - New Reference Setup Wizard for initializing target pitch distribution. These new features allow TrueProp users to tackle a variety of propeller jobs, expanding beyond the pitch measurements with supplemental tools to support other aspects of your business, such as repair cost estimation, customer RPM adjustments, and propeller repitch requirements. TrueProp continues to innovate and refine the next generation of propeller inspection software. We strive to support any propeller inspection device, including Linden DDS, Hale MRI, Prop Scan, Prop View, and many others! Figure 2 - Local Pitch bar graphs visualize the pitch progression from leading to trailing edge for each radius.
Adam Kaplan (TrueProp Software), Gary Linden (Linden Propeller), and Larry Kindberg (AccuTech Marine Propeller) collaborating on the TrueProp / Prop Press 360 installation and set-up. Spring has arrived in the Northeast, along with a new Linden Prop Press 360 complete with TrueProp Software! AccuTech Marine Propeller of Dover, NH has recently acquired this next-generation technology to take their propeller scanning and inspection software to new heights. On April 8, Gary Linden, of Linden Propeller in Iowa, and our very own Adam Kaplan, spent the day with Larry Kindberg and the AccuTech team. They worked on installing this state-of-the-art equipment and software, eager to bring this modern method into the propeller shop. The Prop Press 360, coupled with our software, will allow them to make adjustments and repairs to propellers with greater precision, accuracy, and speed than ever before.
We are pleased to announce that we have launched an Instagram Live series that explores the propeller shops that have implemented TrueProp Software. We tour their shop, get a sense of their company, and chat about their TrueProp decision and its business role. So far, we have gone Live with customers both home and abroad. Every broadcast, we welcome viewer participation and questions in the comments section.
Miss a Live or want to relive all the prop fun? Watch our past Lives below: As we get closer to celebrating the start of a New Year, we would like to reflect on some major additions to TrueProp Software. These new expansions go beyond the traditional software component and truly add new value to the TrueProp you know and love. We genuinely enjoy working with propeller shops worldwide and the insights many owners bring to our developments. TrueProp Virtual Plug-In Launched!This revolutionary process allows general-purpose 3D scanners to be used for propeller inspection in place of a digital pitchometer! Popular with propeller manufacturers, shipyards, and port authorities, the TrueProp Virtual Plug-In represents the latest technological advances in propeller measurement technology! Engineering Services and Replacement PartsNew services available to refresh, convert, and update existing pitchometer systems with appropriate hardware and TrueProp Software. Suitable replacement parts for existing systems can also be sourced with the help of our engineers' detailed knowledge of metrology systems. Prop Scan Upgrade Kit Launched! TrueProp recently presented our upgrade kit for the Prop Scan electronics and encoders. The upgrade kit is designed for Prop Scans with damaged or failing electronics hardware. With OEM parts completely out of production, this upgrade is the best way to extend the life of your Prop Scan machine! Online Education HYDROCourses Available via Partner Company HydroComp, Inc.In response to growing demand for professional education, our partner company HydroComp, Inc. is now offering online courses on a variety of propeller topics, including propeller selection and repair topics sponsored by TrueProp Software. Coming in 2022...
TrueProp's commitment to quality means that our software capabilities are continuously refined based on the valued feedback from our users! Before we ring in the new year, we'd like to reflect on how far TrueProp has advanced in 2021. Just like everyone, we had some resolutions going into this year, and we are happy that we can check off many developments. Plus, we've had a blast working on these new features and seeing them implemented at your shop. Dark ModeBe tempted by the Dark Side! TrueProp now supports Light, Cool, and Dark modes for easy, high-contrast viewing! Built Bigger BetterTrueProp's text and line size are customizable so viewing boxes and radius plots are comfortable on any screen size or viewing distance. Other new options include line style, grid and axis values, and zoom factors. |
TrueProp Software LLC www.truepropsoftware.com measure@truepropsoftware.com Tel: 1-603-868-3366 |
Download this press release: |
Adam Kaplan, CTO, had the pleasure of being featured on the official podcast of the National Marine Propeller Association, Prop Talk. Take the time to give this episode a listen, and you'll be immersed in an enlightening discussion about cup, pitch, rake, camber, and technology's role in propeller design, repair, and performance analysis.
In August 2020, TrueProp Software hosted our first free public educational webinar. View all of our webinar recordings here and sign up to receive notices of upcoming presentations.
An interview with Ignacio Molina of Padgett Swann Machinery
It is the job of engineers to seek creative solutions to complex problems. These solutions are not always obvious, but the experienced engineer knows that using the highest quality tools makes finding answers much easier. In order to learn what can be accomplished by the correct tools in the right pair of hands, HydroComp interviewed Quality Control Manager Ignacio Molina, of Padgett Swann’s Tampa, Florida USA branch.
Ignacio graduated from university in Cuba in 1994. With a background in mechanical engineering, he began working for Padgett Swann’s marine division (Tampa, FL) in 2005.
It is the job of engineers to seek creative solutions to complex problems. These solutions are not always obvious, but the experienced engineer knows that using the highest quality tools makes finding answers much easier. In order to learn what can be accomplished by the correct tools in the right pair of hands, HydroComp interviewed Quality Control Manager Ignacio Molina, of Padgett Swann’s Tampa, Florida USA branch.
Ignacio graduated from university in Cuba in 1994. With a background in mechanical engineering, he began working for Padgett Swann’s marine division (Tampa, FL) in 2005.
Padgett Swann offers a variety of services, such as machining, repair, and manufacture of ship systems. They work with propulsion shafting, propellers, CPP components, heat exchangers, and marine structures. Ignacio started there as a machinist (since there were no engineering positions available at the time) and worked his way up to his current position as Quality Control Manager. Padgett Swann had been using HydroComp’s PropCad and PropExpert software before Ignacio arrived at the company. Ignacio instantly recognized the software’s potential. “I found PropExpert was a very useful tool for what we do,” Ignacio explains. He tells us how he uses the software to calculate the relationship between propellers and engines: obtaining the RPM-horsepower curve. PropCad was very helpful geometric design, as well as reverse engineering for inspection. |
Recently, Ignacio has become more involved with HydroComp’s new sister company, TrueProp Software LLC. TrueProp is software for propeller inspection and repair. Now Ignacio incorporates both TrueProp and HydroComp’s PropCad CAD software, along with their digital pitchometer, to inspect propellers and generate reports.
“TrueProp is efficient, effective and accurate. It captures everything we need, everything we are looking for. Combined with our other technology, it generates reports very quickly as well.”
This is important for Ignacio, since Padgett Swann works with a large variety of propellers, some so big that during inspection they require the machinery to be realigned several times. “No matter how careful you are, you always lose accuracy when you have to realign. There’s no preventing it.”
“TrueProp is efficient, effective and accurate. It captures everything we need, everything we are looking for. Combined with our other technology, it generates reports very quickly as well.”
This is important for Ignacio, since Padgett Swann works with a large variety of propellers, some so big that during inspection they require the machinery to be realigned several times. “No matter how careful you are, you always lose accuracy when you have to realign. There’s no preventing it.”
Though TrueProp is developed marine propellers, Ignacio has found it useful in other circumstances. He has also been applying TrueProp to inspect and reverse engineer water pump impellers. The software has allowed him to inspect the pitch and other geometry of this different kind of system. Padgett Swann and TrueProp have also been developing new inspection integrations, using general purpose laser scanning technology to perform a non-contact inspection of the propeller. This technology is a unique to TrueProp – allowing our users to inspect propellers without ever removing them from the vessel. Several of our TrueProp customers are using this technology to scan large propellers. Over the years, Ignacio has developed a very close relationship with HydroComp staff. He’s been to training classes and frequently benefits from HydroComp’s customer support. He speaks about the staff with great familiarity: “Any time I call it is like talking to a good friend. The staff knows about all sorts of little things that we use here all the time. All of my questions are answered, and I am always given the help I need.” |
HydroComp’s Adam Kaplan comments on his close professional relationship with Ignacio: “Working with Ignacio and the team at Padgett Swan is a pleasure. We have been supporting them for many years with their use of PropCad and PropExpert. Ignacio and I work together regularly through phone, email and screen-sharing sessions. Ignacio uses almost every feature in PropCad and TrueProp – it has been a very beneficial partnership that has led to new capabilities for their company and robust software improvements for HydroComp and TrueProp.
Ignancio’s relationship with HydroComp has been a recipe of keen minds, superior tools, and the desire to continually improve and educate. When someone like Ignacio is offered continued opportunities to advance their craft, they don’t waste time. By coupling this energy with cutting edge advanced propeller tools, there are no limits to what can be accomplished.
Download the full interview here: PadgettSwannInterview.pdf
For more information, please contact:
Ignancio’s relationship with HydroComp has been a recipe of keen minds, superior tools, and the desire to continually improve and educate. When someone like Ignacio is offered continued opportunities to advance their craft, they don’t waste time. By coupling this energy with cutting edge advanced propeller tools, there are no limits to what can be accomplished.
Download the full interview here: PadgettSwannInterview.pdf
For more information, please contact:
HydroComp, Inc. Tel +1.603.868.3344 Jill.aaron@hydrocompinc.com www.hydrocompinc.com | Padgett Swann Tel +1.813.247.3478 imolina@padgettswann.com www.padgettswann.com |
The Leading Edge is a members-only publication from the National Marine Propeller Association. The NMPA is the largest professional society for propeller manufacturers, repair shops, and propulsion equipment vendors. TrueProp is proud to be a contributing member of the NMPA!
Durham, NH – Adam Kaplan, CTO TrueProp Software
If you attended the NMPA Convention this past November, perhaps you saw the panel discussion on repairing new propeller designs. Although many popular designs still use a flat-face, the industry has seen a notable increase in new, contemporary propeller designs such as Veem’s Sportfish and Michigan’s Marlin props. These propellers are deliberately designed for high performance and feature unique geometries that manufactured by CNC machining.
If you measure one of these new propellers, you are likely to notice that the local pitch varies across the blade surface. Let’s quickly review some of these variations…
First, let’s review the propeller from the root to the blade tip. On a traditional propeller, we would expect that the section pitch to be the same at all radii – this is referred to as constant pitch. For example, on a 20 inch pitch propeller with constant pitch, the 50R, 70R, and 90R all measure to 20 inches pitch.
If you attended the NMPA Convention this past November, perhaps you saw the panel discussion on repairing new propeller designs. Although many popular designs still use a flat-face, the industry has seen a notable increase in new, contemporary propeller designs such as Veem’s Sportfish and Michigan’s Marlin props. These propellers are deliberately designed for high performance and feature unique geometries that manufactured by CNC machining.
If you measure one of these new propellers, you are likely to notice that the local pitch varies across the blade surface. Let’s quickly review some of these variations…
First, let’s review the propeller from the root to the blade tip. On a traditional propeller, we would expect that the section pitch to be the same at all radii – this is referred to as constant pitch. For example, on a 20 inch pitch propeller with constant pitch, the 50R, 70R, and 90R all measure to 20 inches pitch.
On contemporary propeller designs, the section pitch changes from the root to the tip in order to better match the inflow under the hull – this is referred to as variable pitch. We often see the highest pitch at the 70R, with decreasing pitch at the root and tip. For example, a 20 inch pitch propeller with variable pitch could have a pitch of 19.5 in the 50R, 20.5 at the 70R, and 19.5 at the 90R. The average pitch for the propeller is still 20 inches, but the distribution of section pitch is variable from the root to the tip.
Next, let’s review the propeller from the leading edge to the trailing edge. Again, on many traditional propellers, the propeller face is flat – as a result, the local pitch is the same on the leading edge, the middle, and the trailing edge of the blade. In the previous example of a 20 inch pitch, this means that the first local pitch segment will measure as 20 inches, as will the second and third segments (and so forth). We refer to this as a flat-face/constant pitch foil shape (technically, the term is Ogival).
However, contemporary propellers will have variation in the local pitch from the leading edge to the trailing edge. This is because these propellers utilize camber (additional curvature in the face of the blade) to increase performance. Often, the local pitch increases from the leading edge to the trailing edge – so many people refer to these designs as a cambered-face/progressive pitch.
When repairing propellers, it’s important to review and understand the intent of the propeller’s design. Is the variation in pitch due to damage or was that the design intent? Is this propeller a traditional design, where the face of the blade is flat and the pitch is uniform across all radii? That would be a constant pitch propeller with a flat-face… Is there more to the design? Is this propeller a contemporary design, with section pitch varying from the root to tip, like a variable pitch prop? Is there variation in the local pitch from leading edge to trailing edge, like a cambered faced/progressive pitch propeller? These are important questions to answer before you begin reworking the blades!
We wish everyone a successful 2020 and look forward to seeing all of you at the 2020 convention!
Did you enjoy this article? View PART 2 - Progressive Pitch: Performance at HydroCompInc.com!
We wish everyone a successful 2020 and look forward to seeing all of you at the 2020 convention!
Did you enjoy this article? View PART 2 - Progressive Pitch: Performance at HydroCompInc.com!
Download the full article... Provided with the permission of the NMPA. |
Learn more about the propeller sizing, design, and repair tools offered by TrueProp and our sister company, HydroComp, in the November 2019 issue of Marine News!
What started as a one-off software development project for a single client has grown into a company that helps propeller designers and manufacturers make better products. TrueProp was founded in 2017 as a sister company to 35-year-old HydroComp in Durham. HydroComp develops performance prediction software for naval architects and shipbuilders to aid in the design and analysis of ship hulls and propellers.
TrueProp Software selected FINALIST for the 2019 New Hampshire Granite State Growth Competition!
5/29/2019
It is an honor to announce that TrueProp Software was named a finalist in the 2019 Regional Economic Development Center’s (REDC) Granite State Growth Competition. The competition showcased young and innovative New Hampshire businesses. The Granite State Growth Competition started with more than thirty applicants. After participating in several rounds of pitching and narrowing the numbers of competitors, a panel of judges selected TrueProp Software as one of five finalists.
These propeller shops upgraded their measurement practices by installing TrueProp Software into their existing (or shop-made) measurement devices.
Wondering how they did it? Contact us!
Wondering how they did it? Contact us!
and why it's important to take a close look...
Propellers are a critical piece of boating equipment. Many boat-owners know the cringing sound of a propeller strike - whether it’s a log, rope, or running aground, that impact resonates across the deck, through your shoes, and right to your wallet. To get back on the water, you might choose to have the prop repaired at a reputable propeller shop. (P.S. The National Marine Propeller Association, NMPA.org, can help you find a certified shop in your area!) These shops utilize computer-assisted measuring equipment to inspect and repair damaged propellers to better-than-new condition.
It’s often said that propeller repair is a blend of both art and science. This is absolutely true, and experienced repair professionals can save heavily damaged propellers. Many shops, proud of their work, provide inspection reports to customers to document the before and after conditions of the propeller. These reports contain a wealth of information, but many boat-owners have questions when reviewing them. In this article, we will go over the format of a standard propeller scan report, as well as discuss a few tips on how to interpret it. Let’s start with the first part of the report you read, the heading.
The Report Heading
The heading gives information about the repair shop, the customer, and equipment used, as well as the date and whether the report is for the initial condition or the final condition.
Inspection Criteria
When a shop inspects your propeller, most times they are checking the position and size of each blade in multiple locations. The positions and sizes should match from blade to blade, within some acceptable margin. This margin is known as a tolerance. For inspecting propellers, the tolerances for the geometric accuracy are based on the International Standard Organization's rules for propeller manufacturing. The standard is ISO-484 and it has 4 levels of increasingly tighter tolerance “classes”.
Propellers are a critical piece of boating equipment. Many boat-owners know the cringing sound of a propeller strike - whether it’s a log, rope, or running aground, that impact resonates across the deck, through your shoes, and right to your wallet. To get back on the water, you might choose to have the prop repaired at a reputable propeller shop. (P.S. The National Marine Propeller Association, NMPA.org, can help you find a certified shop in your area!) These shops utilize computer-assisted measuring equipment to inspect and repair damaged propellers to better-than-new condition.
It’s often said that propeller repair is a blend of both art and science. This is absolutely true, and experienced repair professionals can save heavily damaged propellers. Many shops, proud of their work, provide inspection reports to customers to document the before and after conditions of the propeller. These reports contain a wealth of information, but many boat-owners have questions when reviewing them. In this article, we will go over the format of a standard propeller scan report, as well as discuss a few tips on how to interpret it. Let’s start with the first part of the report you read, the heading.
The Report Heading
The heading gives information about the repair shop, the customer, and equipment used, as well as the date and whether the report is for the initial condition or the final condition.
Inspection Criteria
When a shop inspects your propeller, most times they are checking the position and size of each blade in multiple locations. The positions and sizes should match from blade to blade, within some acceptable margin. This margin is known as a tolerance. For inspecting propellers, the tolerances for the geometric accuracy are based on the International Standard Organization's rules for propeller manufacturing. The standard is ISO-484 and it has 4 levels of increasingly tighter tolerance “classes”.
Measurements Positions
The pressure face of the propeller is measured at several pre-defined locations. These locations are described as a percentage of the blade’s length (or more accurately, the blade’s radius). You may see data reported for these positions; for example, “70R” indicates the measurements are taken at 70% of the blade’s length. The higher the class accuracy, the more measurement positions are required.
The pressure face of the propeller is measured at several pre-defined locations. These locations are described as a percentage of the blade’s length (or more accurately, the blade’s radius). You may see data reported for these positions; for example, “70R” indicates the measurements are taken at 70% of the blade’s length. The higher the class accuracy, the more measurement positions are required.
Bar Graphs
The ISO criteria require inspection of many different parameters of the blades. Propeller performance is greatly influenced by the propeller’s pitch, or the angle of the blade. There is an average pitch for the entire propeller, as well as a pitch for each blade. There is also pitch reported for each blade’s measurement locations (i.e. 50R, 70R, 90R). The reports tend to use Bar graphs to report the Pitch of each blade at the measurement locations (ex. “70R” will have a pitch value and bar graph for each blade). Overlaid on the bar graph results is the tolerance window, which gives us the minimum and maximum acceptable pitch for the desired Class. Measurements of pitch that exceed the tolerance window must be adjusted and repaired to meet the desired Class. The measurement locations (i.e. 70R) can also be broken up into smaller segments to ensure the pitch is consistent from the leading edge (forward edge) of the blade to the trailing edge of the propeller (aft-most edge). This is known as local pitch and is required for the higher repair classes.
The ISO criteria require inspection of many different parameters of the blades. Propeller performance is greatly influenced by the propeller’s pitch, or the angle of the blade. There is an average pitch for the entire propeller, as well as a pitch for each blade. There is also pitch reported for each blade’s measurement locations (i.e. 50R, 70R, 90R). The reports tend to use Bar graphs to report the Pitch of each blade at the measurement locations (ex. “70R” will have a pitch value and bar graph for each blade). Overlaid on the bar graph results is the tolerance window, which gives us the minimum and maximum acceptable pitch for the desired Class. Measurements of pitch that exceed the tolerance window must be adjusted and repaired to meet the desired Class. The measurement locations (i.e. 70R) can also be broken up into smaller segments to ensure the pitch is consistent from the leading edge (forward edge) of the blade to the trailing edge of the propeller (aft-most edge). This is known as local pitch and is required for the higher repair classes.
Other Criteria
While pitch is an important parameter, ISO-484 includes other checks on the blade shape and position. The length of the blade at each measurement location is known as the chord length. Chord length is reviewed because it is important to maintain the same surface area for each blade. The spacing between blades as well as the position of the leading edge of each blade is checked for consistency. Blade spacing is important for smooth and quiet propeller performance. Lastly, the axial position of each blade is checked. This ensures that each blade is raked (or swept backward) the same amount. (This is sometimes referred to as propeller track.)
Compliance Summary
There is typically a statement of compliance (or non-compliance) near the top of the report that gives the overall pass/fail status of the propeller with respect to the desired Class accuracy.
While pitch is an important parameter, ISO-484 includes other checks on the blade shape and position. The length of the blade at each measurement location is known as the chord length. Chord length is reviewed because it is important to maintain the same surface area for each blade. The spacing between blades as well as the position of the leading edge of each blade is checked for consistency. Blade spacing is important for smooth and quiet propeller performance. Lastly, the axial position of each blade is checked. This ensures that each blade is raked (or swept backward) the same amount. (This is sometimes referred to as propeller track.)
Compliance Summary
There is typically a statement of compliance (or non-compliance) near the top of the report that gives the overall pass/fail status of the propeller with respect to the desired Class accuracy.
Evaluation Summary
In addition to the overall compliance, sometimes the compliance of an individual criterion (pitch, chord, blade spacing, track, etc.) is detailed. This provides a nice overview of the work required for damaged propellers or the work performed on repaired propellers.
Wheel View
Some software, such as TrueProp, includes a wheel view that displays the shape of the propeller as seen from above. This view is great for finding the damaged regions on the propeller, which are usually marked with a different color or large dot. The wheel view often includes the spacing between blades, as well as reporting pitch values for each blade and the average of the propeller as a whole.
Some software, such as TrueProp, includes a wheel view that displays the shape of the propeller as seen from above. This view is great for finding the damaged regions on the propeller, which are usually marked with a different color or large dot. The wheel view often includes the spacing between blades, as well as reporting pitch values for each blade and the average of the propeller as a whole.
Tabular Data
In a full report (not usually provided to the customer), the dimensional values for the blade parameters are listed. The repair technician can compare these values to the expected values in order to determine how to repair the propeller. While this data is extensive and hard for a boat-owner to understand, it is essentially a tabular version of the bar graphs and wheel plot data. If you are interested in learning more about this propeller data, we encourage you to talk with your repair professional or contact TrueProp Software.
They say: “knowledge is more valuable than money,” and
this extends to high-quality propeller repairs
So next time you damage your propeller, remember that often the propeller can be repaired to better-than-new condition by a professional propeller repair shop. The inspection information provided by repair shops can be intimidating and non-intuitive for boat-owners, but a little knowledge about the inspection process and standards can help you interpret your own scan report and ensure your propeller has been repaired to as-good or better-than-new condition.
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