Propeller (Heads)
by John Curnow, Global Editor, Powerboat.World 10 Mar 2021 22:00 UTC
Otam 80HT Attitude © Sand People
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In recent times, I have been decidedly deep in some America's Cup and foiling designs. Yes. Propellerhead caps, and pocket protector type stuff. Then when I read what is below, I could not help but feel that there was one serious parallel here. Namely, multiple elements all in play at once, and all affecting the others... However, rather than wind, mast height, sail shape, foil geometry and flight control, what struck me was how cost, weight, power, usage, generation/storage, fuel cell, even geography was a huge set of variables to review in the solar/electric/hybrid field.
Marc Hawxhurst, the President of Nova Luxe, was very kind in then allowing me to reprint his material herewith, so I guess without further ado, here is his guest editorial if you will...
As we bring our eLite series of yachts to life, and as our re-fit business gains momentum, it's important to keep an eye on equipment developments. Nova Luxe means 'electric done right', and as such, we must always offer our customers the best solution for their application. Here we share the information that we have learned whilst evaluating different products.
Parallel Hybrid versus Serial Hybrid for new builds
Deciding which is the better choice depends on the desired performance of the yacht. My position has been that a serial hybrid system with Torqeedo equipment is the best system for a 35'-50' power catamaran. This however, assumes that full power would only be used for a short period. Torqeedo does not have a generator powerful enough to support full speed for more than an hour. Max genset size at this time is 25kw, and max motor size is 100kw. (Quarter throttle speed can be used as long as fuel is in the tank, not full speed.)
For a serial hybrid system that can operate at its rated motor voltage of say 100kw, you would need to use the UQM system. UQM was recently purchased by Danfoss, and we expect the system to get even better under the Danfoss roof. UQM motors and gensets are available at sizes above 200kw. Customers have been asking and it's possible to do, yet I do not recommend sizing the gensets to fully power the motors. To do so, you would need four UQM 100kw motors. One is placed on each shaft and two are placed on the back of two turbo diesel motors (Hyundai ~250hp). Add in the batteries, and the weight of this system, and its total cost, is high.
So, how long do you expect to operate at full speed? Realistically, this system will float around for years never operating at peak speed for more than an hour. If the gensets were sized for 20-50% of capacity, cost and weight fall significantly. Very simply put by a fellow boat builder, "Boats are like sex, you need to be able to hit that top gear, but you won't operate that speed much of the time."
All about the speed
For those who do actually want to run at a high cruise speed for long durations, Parallel Hybrid has greater merit. We have been working with Steyr and Transfluid to develop the proper system. Steyr motors are small, light and will burn anything. The Italian company Transfluid purchased BellMarine about a year ago, and are shaping up to be a serious player in the hybrid space. Transfluid offers a clutch that allows one or two electric 'machines' of 10-50kW to be attached to the shaft. Using the smaller, liquid cooled 20kW motors is desirable, as they only require a 96v system.
Two of those motors will give you the 6-7 knots as electric, just perfect for harbour, or channel cruising. When you want excess speed, the diesels can run all day at high speed. This hybrid configuration is about half the cost of the former. Also, the system does not need a generator.
Now we don't use secret sauce at Nova Luxe, so I'll fill you in on one more trick. The motors are modified by Integral Solutions and 10kw+ alternators are added to the timing belt side of the motor. Two of those will provide 20kW or 50% of that at idle, which is more than enough energy to cover the house load and charge batteries, eliminating the need for gensets, which is a weight and cost saver.
Also, the electric machines can generate about 50% of their rated power, providing another 20kw of charging ability while the yacht is under way via diesel. Add solar, and this yacht can generate a lot of power, 50kw in an hour! Use both electric and diesel at the same time, and the performance exceeds that of diesel motors 100-150hp larger.
For the eLite 50 we will build on spec, I am leaning towards the Transfluid system over Torqeedo, because I think it would be better received by the US market. Let me know if you have thoughts, one way or the other.
Refit
For re-fits, I reserve the serial hybrid option for yachts with bad motors and/or a value near $1m, as it takes no less than a quarter million to do the job properly. The Transfluid option would work, and that system is closer to $120k. However, two other systems show higher potential. The first I recommend, the second I do not (yet). Elco, the oldest player in the electric motor space, has a solid outboard option that reaches up to 50hp or 26kw. They use a 96v electric system, which can easily be transformed and shared with the house battery bank. Adding two of these electric outboards to a diesel inboard yacht is a good solution. At $35,000 for the complete system this option has serious potential, and I expect to be using more of these units for conversions.
The next player that I do not recommend, only because I have never seen it working and pre-sales support has been lacking, is from Fischer Panda. They offer a shaft-driven, belt drive motor that has the potential to be the lowest cost solution for electric conversion. It would be the cheapest and easiest to install, and if it can be proven effective, the top choice for charter companies looking to market their yachts as electric.
If I worked at Fischer Panda, I would avoid the difficult problem of operating the electric motor in conjunction with the diesel on the shaft. I would also give up the ability to generate power. Doing those two things would make the system far more reliable. Issues arise when the electric machine is attempting to generate power from a shaft that spins at different speeds. If the prop exits the water, the shaft could instantly double its speed creating a voltage spike, which is difficult to handle. I will keep an eye on this product as it has a lot of potential.
Inside running
Two more yachts are being added to the Nova Luxe, eLite series, which are a 70' and 80' tri-deck. It's been in the works for a while now, however we needed to properly vet the electric systems for these behemoths, and that is just completed. With one exception, a Swiss supplier has proposed a hydrogen solution for the 80'. This team was prepared to build a superyacht using only hydrogen, but the project was cancelled at the start of the pandemic almost a year ago.
Hydrogen was originally a DARPA project, but not much has happened with regards to this technology in the USA. I have driven in a hydrogen car and I was underwhelmed with its acceleration. In Europe however, this technology is advancing quickly and the Swiss are at the forefront. Hopefully Nova Luxe will bring the technology back to US shores, but for now, we see it as a European offering.
Visit our website for details on the 70', and if you're thinking about starting an electric conversion feel free to reach out for advice!
All together now
Recently, Gold Coast Maritimo representatives, BMS, departed the Maritimo's Sanctuary Cove office en route for a raft up at Peel Island. Sales Manager, Justin Thorpe explained, "we departed Sanctuary Cove at 930hrs in a Maritimo M59 Cruising Motor Yacht, along with an M64 and an S50. We subsequently met two more boats around the corner at Sovereign Island, and began our journey North. The weather was gloomy, but the spirits where high, and we were confident the sky would clear."
"On arrival at 1130hrs, two other Maritimo's where entering the area who had departed from Raby Bay, and five of us rafted up, with the others arriving by tender. Those who came along were spoilt with the most emphatic weather, a nice high tide, visiting dolphins, and some good times and stories. Thanks so much for the participants and look forward to seeing them again soon."
Power brand and powercats
Powercat brand, Aquila, is going up and down in range from their original base in the forties. Already a hit in the USA, the first of the new Aquila 32 arrived in Australia recently. This one has the half screens and is fitted with a pair of Mercury's x 225hp V6s. You can option up to a pair of Merc's 300hp V8s with JPO (joystick) for about AUD60k more.
Now it's not that long ago the first new Aquila 54 and 70 left the SinoEagle yard for the USA, and for Australians, a new Aquila 54 will be on display at Sanctuary Cove in May. Importantly, she will be resplendent with a 14 foot Aquila cat tender, which will highlight how the brand now extends from 12 to 70 feet.
The Whitehaven Group is now the official Aquila Boats distributor for Australia and New Zealand. On top of all this new activity with Aquila, and existing brand Integrity, presently Whitehaven have strong interest for their namesake brand in both Thailand and New Zealand.
Only a few weeks ago I had the distinct pleasure of climbing aboard the imposing and very new Whitehaven 8000, Panache. She is aptly named, for Panache is superbly appointed, and masterfully tasteful. It is all no doubt a legacy of her repeat customer owners, Ray and Denise, who are very delightful themselves.
Panache is spacious, definitely the result of her significant beam, and the overall sense of freedom it all affords, means she will do her job of long range, and remote cruising with distinct aplomb. Although capable of 24 knots, and a cruise of 20, her owners do a lot more miles at 10 or 12.
Yet for me the real treat is in the engine room. Yes, Ray makes sure you can eat straight off of her D16 V8 Scania 1200hp donks (each with a impressive 4099nm of torque no less), but one of the telling tales is that at 1660kg each (dry), Scania believes these gems to have the best power-to-weight ratio in their class. At any rate, in Panache they are smooth, and certainly have plenty of workspace around them.
For me, however, it's the massive tender garage that hides a high freeboard alloy tender that really tells the story of how Panache will cruise. For where they go along Northern Australia there's no swimming, think massive saltwater crocs, but the bonus is awesome fishing, which her covered marlin platform, rod holders, and filleting boards are a real testament to.
Big boats, even bigger times...
Superyacht Australia recently held their Soirée, and it was especially important, because they actually managed to get some boats there, briefly, as most are enjoying a bumper charter season. CEO David Good explained, "The charter market is so busy at the moment with cruise and international travel unavailable. It's fantastic that eight owners made their vessels available on a Saturday for the benefit of the industry, and to grow it even further. We hope that we have introduced new customers into yachting as a result."
OK. Today you will find that the website has an abundance of material from right across the globe, and if you cannot find something, just try the search button right up the top of the landing page, above our logo.
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Finally. Please look after yourselves,
John Curnow
Global Editor, Powerboat.World