“We are changing our look!” update

From Jill Aaron, Managing Director

As I noted is a post from some months back, 2011 is the year of several changes for the HydroComp brand. So far, we have been on track and have successfully completed two out of three major projects.

I am happy to announce that we have finished revitalizing all four of our software icons; NavCad, SwiftCraft, PropCad and PropExpert. These four icons are now in keeping with their newest family member – PropElements – which was introduced in 2010. Our goal was to have all the software product logos to share a common theme.

Our second project was to revamp our packaging for software shipments. We had been using a petroleum-based binder which was bulky, expensive to ship, and just not friendly to the environment. Our goal for this project was to reduce our carbon footprint while using USA-made eco-responsible packaging materials. In addition to those requirements, we had to be sure our new packaging could withstand the rigors of shipping and not damage the contents. This was no easy feat! It took a lot of detective work to find a local New Hampshire company (well, almost everyone in NH is considered local) to help with this job. After ten long months of discovery, we now have an earth-friendly package which not only protects our products, but is lightweight.

Our third and final challenge has been the most intensive – our website redesign. The intent was to perform a total redesign from the ground up. We are indeed doing just that, but I am sorry to say that we are not yet finished. In our twenty seven years of business, HydroComp has compiled a vast amount of technical content, (which is better for you our clients,) but that makes the process of migrating to a new site a slower one. We are close to when this new site goes “live”, so please do check back periodically, and we will also keep you informed on our Facebook page.

Care and feeding of your small thruster

Miscellaneous Musings from Don MacPherson, Technical Director

Ocean Tech Expo is a small conference and expo for the submersible community. It was held last week in Newport, RI.

Most of the major players in ROV and AUV vehicles were exhibiting, and I was very pleased to see many of our HydroComp thruster design clients exhibiting vehicles. I had the opportunity to speak to the conference attendees, as part of a SNAME session, with a presentation entitled “Contemporary Thruster Design for Submersibles”.

But enough about that… One thing nagged me the whole drive back to New Hampshire.

As we sit in the designer’s chair, we miss having to deal with the messy practical side of thruster operation – and yet, the practical application of thruster operation should affect design decisions. Let me share some a few things that I saw regarding the “care and feeding of your small thruster”.

First, the picture below is a unit we designed for a vehicle operator (that was eventually passed back up the chain for adoption by the manufacturer). It has proven to be a very nice performer for the vehicle.

I want to illustrate a few small deficiencies that, while certainly not of any major concern, might help to make the thruster an even better performer.

Nozzle-propeller symmetry

In a ducted thruster, tip clearance affects efficiency, as does keeping the propeller fully symmetric with the nozzle. Small tip clearances are better, but this requires tighter tolerances and more dimensional stability.

The image here confirms that the nozzle is not axi-symmetric with the propeller. There is greater clearance to the top blade than to the bottom.

Is this critical? Probably. Remember that for an increase in tip clearance of 1% of diameter, you will see some 3% reduction in efficiency. Combine that with the imbalance in developed thrust, and the practical implications can be meaningful.

How can you avoid nozzle-propeller asymmetry? Make sure that the nozzle attachments (i.e., struts) have sufficient strength and stiffness. As you can see from the first picture, the attachments are made from a relatively flexible plastic material. They should be changed to a stiffer material.

Viscous drag and roughness

At such a small size, roughness can be huge. The propeller is made from a metal that has had a chance to corrode a bit. Keep your propellers and nozzles clean and smooth. Having said that, be careful that any polishing or buffing of the propeller does not alter the shape of the propeller, particularly on the nose.

Nozzle edges

A part of the design of the nozzle is a trailing edge shape that promotes separation per an intentional design objective. So, the shape of the nozzle should also be clean and smooth, and the trailing edge should also be sharp.

This picture is a detail of the trailing edge. You can see how it has been roughened from impact and handling. Take a minute with some fine grit sandpaper to return the trailing edge to a sharp corner.

Flow discontinuities

Take a look again at the top picture. You can see cutouts and holes in the nozzle that allow for different fittings. When these fittings are not required,however,  it would be helpful to fill these to improve water flow. Any discontinuity is just costing you thrust or battery life.

Summary

These small considerations may not “make or break” a design, but they are relatively simple things that can keep your thruster healthy and well fed.

We are changing our look!

From Jill Aaron, Managing Director

The coming year will bring significant modifications to our website. We have been feverishly working on a redesign now for many months and are very excited about the new changes. Some of the changes are small while others will be fairly comprehensive.

In particular, we wanted a more vibrant color scheme, a new user friendly design, improved page layout and increase functionality. There will be a special section for MSU support and subscriptions so our community of users, supporters and friends will have a place to find the information they need when they need it. The latest news and upcoming tradeshow and training events will be more prominently displayed.

This is just the beginning of the process. We are eager to have this completed and are anticipating to have this new website up and running by summer 2011. We welcome your feedback on how you use our website, and how you think we can make the new site more effective. So keep checking back while we begin the countdown to the unveiling…

www.hydrocompinc.com

PropElements nominated for 2010 DAME Award

Of the products entered in the 2010 Design Awards METS (DAME), the Jury has selected 63 nominees from 13 countries to complete in eight categories. We are delighted to note that our PropElements™ detail propeller design and analysis software was nominated to the Marine Related Software category. Overall and category award winners will be announced at METS.

Wish us luck!

Check out PropElements (and other HydroComp products) at METS stand 4.406, Nov 16-18.

The changing winds of summer…

From Jill Aaron, Managing Director

The summer of 2010 has brought changes to our world here at HydroComp. We have our Facebook page up and running, (please join!), a fresh new update of our iconic logo, and we released a brand spanking new amazing product  – PropElements. But, more sadly, we have had to say goodbye to our dear European marketing arm, Nick Danese of Design Systems & Technologies (NDAR). Perhaps goodbye isn’t a good choice of words here. Nick is not leaving the HydroComp family entirely, but simply resigning his formal sales and marketing association with us. After almost twenty years of intensive collaboration, Nick felt it was the proper time to make a change. Nick Danese has been an important part of HydroComp’s tremendous growth in the E.U. and Middle East, as well as part of a joint team for trades shows, sales, and technical development. He will continue to be an active participant in the HydroComp team for technical matters and we look forward to his continued presence, (and good strong coffee!).

On the flip side, we are pleased to announce that HydroComp’s new agent for Europe is Adrián Sarasquete, Director of VICUS DT. Adrián is not new to HydroComp software. A commercial user of HydroComp’s flagship NavCad and PropCad software for over five years, Adrián brings a special set of experience and technical background to the HydroComp team. His company, VICUS DT, is a technologically dynamic and innovative company that focuses on hydrodynamic research and development in the shipping, industrial and energy sectors. His role as European representative will encompass sales, marketing, technical development, and after-sale technical support.

A good place to meet and welcome Adrián will be during our upcoming 2010 Propeller Workshop METS. This is being held in Amsterdam on 15 November, the day before METS 2010 begins. Many of you have asked us to bring our training and Donald’s vast expertise “across the pond”, and we listened. Our April 2010 Propeller Bootcamp was wildly successful and sold out quickly, so you won’t want to miss this excellent intensive day filled of marine propeller design and analysis. Visit our website for further details and to register. Remember: It doesn’t matter how you design your propeller…until it does…

Then there is the METS show itself from 16-18 November in Amsterdam. Together we will have Donald MacPherson, Adrián Sarasquete and Nick Danese all together at Stand 04.406. I can confidently say that all other stands at this show will lack in comparison to the strong background of propeller knowledge, hydrodynamic experience, and last, but not least…charm.

Detailed propeller design for naval architects

Miscellaneous Musings from Don MacPherson, Technical Director

It has been a few months since our PROPS2010 Bootcamp, and we have used the time to reflect on the class, our participants, and propeller design in general. First and foremost, we are grateful to our participants for the time that they spent with us away from family and work, and for their open interaction during topic discussion. It is this type of give-and-take between participants that make these events special.

This group helped us galvanize our opinion that “detailed propeller design and analysis” is indeed within the reach of any practicing naval architect. They also made clear that it is completely relevant to virtually any new ship design, and even to repowers. No longer “black magic”, detailed propeller design and analysis is a mature, reliable discipline. The first step to effectively utilizing detailed propeller design in the course of a naval architect’s day-to-day work is an engineering understanding of its principles, objectives, and expectations. Detailed propeller analysis is not for the uninitiated, but neither is it beyond the reasonable scope of any naval architect or marine engineer that has the inclination to do a little reading and professional development.

A direct outcome of the Bootcamp is the on-going development of a training curriculum for detailed propeller design. This will principally complement our new PropElements detailed propeller design and analysis tool. (PropElements is available now in a Pre-Release distribution, and will be officially released fourth quarter 2010.) We are currently reaching out to a few other companies with notable propeller design experience to assist with the development of the curriculum content.

(The next class is being planned for November 15th in Amsterdam to coincide with the METS trade show. Please email us if you would like to receive additional details information about this class.)

Most naval architects are not in the business of designing propellers for manufacture, so the relevance of detailed propeller design and analysis to the broad NA/ME community may not be obvious. Consider this recent example of where a naval architect might benefit from having an in-house propeller design capability:

We were contracted to provide guidance on the selection of proper gear ratio for a variant of an existing tugboat design with some 35% more power. The propellers and nozzles had already been ordered and delivered. (Of course, choosing the transmission ratio after buying the propeller is…, well, you know…) It became clear very early in the analysis that we needed to find an available ratio as close as possible to the ideal ratio, and then repitch the propeller. Having a detailed design capability allowed us to a) determine that the best distribution of the repitch was not simply a constant change in pitch from root to tip, and b) to provide some measure of what various pitch distributions might offer in improved efficiency. This had nothing to do with building a propeller, but it still employed detailed propeller design, none-the-less.

This capability can also be used for enhanced propeller performance analysis, and the qualitative evaluation of design variants:

• How much change in tip pitch do I really need to measurably change local cavitation number?
• What are the implications of high skew on blade stress and safety factor?
• How would a change in inflow wake distribution (by altering a ship’s stern lines) affect performance, efficiency, and cavitation?

These questions and more can be easily answered by a trained naval architect or engineer (a Bootcamp graduate!) with the detailed propeller design and analysis tools that are easy-to-use, reliable, and well-behaved (such as PropElements).