This Plugboats Podcast features a conversation at the world’s largest Boat Show in Düsseldorf, Germany, with Tom Dowdell, Head of Marketing for Williams Jet Tenders and Josh Stoddard, Head of Engineering at EVOA, a US developer of high power electric boat drive systems that was contracted by Williams to do an all electric version of their EVOJET 70.

The EVOJET 70e was a Finalist in the 2024 Gussies Electric Boat Awards, and another EVOA powered boat, the Mastercraft NXT21, was a nominee.

See all Finalists  in the 2024 Gussies Electric Boat Awards

You can listen to the podcast here or on »» Apple. The transcription below has been lightly edited for the written word.

Jeff Butler, Plugboats:

Before we get going here, Tom, can you just tell us a little bit about Williams Jet Tenders?

Tom Dowdell of Williams Jet Tenders:

Yeah, sure. So we we make about 1,000 boats in our factory in Oxfordshire in the UK, which makes the biggest boat builder in the UK by volume. We’ve been going for 20 years. We employ about 140 150 staff in total. We have over 40 dealers all over the world, from USA to Asia, Australia and all throughout Europe. And the focus is is on Jet tender.

So a tender for yachts, yachts in a certain size can’t get close to the shore. So they use the tender for journeys from ship to shore carrying passengers, but can also use them for things like water sports and social activities and just generally exploring the local area.

When Williams says ‘electric’ it’s big news

JB: So when William says, let’s do something electric, it’s big news in the tender and yacht world.

TD: Correct. Yeah, it was big news. And it was a big it was a big step for us, and it’s something that we have been talking about for several years. I remember it coming up, certainly over five years ago, we didn’t think we were ready, or the market was ready to take it at that point in time

JB: And how you think the market is getting there and will grow for the future?

TD: It’s a good question. A lot of it will be driven from the big super yachts and shipbuilders they want to incorporate new technology, and one of them is an electric tender. And we’ve had requests from customers and from OEMs, and we wanted to show what is out there and what’s possible.

We have our boat here at Düsseldorf, the EVOJET, which is a seven meter boat, and we thought that is a great vessel for the technology. And obviously we partnered with EVOA on this journey. But I guess we’ll get into the into the project, details of how it all went.

JB: Josh, can you tell us a bit about your background? Were you always in electric boats?

Josh Stoddard of EVOA:

So my background is automotive engineering. I kind of got my start with electrification in graduate school. I was developing plug and hyper electric vehicles. Ultimately, I worked at General Motors for a handful of years, doing vehicles for the army, as well as engine control software prototype EVs and things like that. So that’s the background. Eventually came down to Orlando, Florida to do electrification in the boat world.

JB: And how did it come about that Evola got together with Williams?

JS: EVOA wants to partner with the preeminent manufacturers in their category. We have a high quality product, you know, performance driven, and so does Williams. We had actually had made a visit a few years prior on one of our traditional business trips, and just let them know that we existed, you know, planted that seed, and when it came time for them to decide on who should they should partner with, from electrification front, they knew that we were able to provide the technology to meet their performance requirements to fit into the EVOJET.

JB: Tom, Williams already has a very successful EVOJET 70 diesel powered so how do you go about taking that and saying, we’d like to make an electric version?

TD: What we normally do at Williams is we come up with a project brief, so we highlight what we want to achieve from it, and we highlight, you know, any any suppliers or key stakeholders in that who can help us deliver that, being, you know, if they were in this situation, performance is in our DNA as a company, that is what you know, driving a Williams, it makes you feel alive, and that is what our customers like.

‘Top speed is 40 mph for this boat’

So we can have a compromise on that. So the top speed is still 40 miles an hour for this boat. But then it was also the range. And obviously range is a gray area, because it depends how fast you go, how you’re performing, you know how much charge you get.

JB: Josh, maybe you can tell us a bit about how you meet those criteria that Williams had set up for you. You have the requirement of needing to match the top speed of 40 miles per hour. But diesel packs a lot more energy into a kilogram than a battery. How did you manage the range aspect?

JS: Ultimately, it’s a balancing act of how much energy storage Do you want to put in with your batteries versus how much weight do you want to have with your batteries. Williams is known for producing a high performance product, and by adding an excessive amount of battery storage, we’d also be adding a lot of weight, and we ultimately elected not to go that route.

Read: New Supra Towboat powered by 320 kW EVOA drivetrain

You’s sacrifice the handling of the boat. It’s harder to turn slower to get on plane. Your top speed is sacrificed. And that’s not what we wanted with this boat. So ultimately, what we decided was to try and match the weight of the diesel, and that means that we put 60 kilowatt hours of energy storage in the inch compartment, and no more. And while you’re not going to have a four hour run time, what you are going to have is a very consistently performing product that matches with the rest of the Williams line, and that was the goal.

‘No compromise on performance or handling’

There’s no compromise on the performance or the handling of the boat. When you go to an electric you’re only going to see the benefits of reduced noise quicker to plane because we kept the weight the same. And that was a massive driving target for the entire design of this project.

JB: That kind of begs the question, Tom – what is the usual range that a the Williams Jet Tender would need?

TD: We have a typical range of how you would expect to drive the tender. So it would be a period of time where you’d be limited to, say, five to 10 miles an hour, where you’re coming out with the harbor. You’ve got harbor limits. And also you would approach the yacht at a low speed as well. So they’re the two areas which you would have a low speed running. Then in the middle, where you’re on the plane, about sort of 15 miles an hour. To 20 miles an hour is like your typical cruising speed. And then also a short period of high performance top speed running, so 37 plus miles an hour,

JB: So, did you put together a team from the two companies?

TD: We had one of our technical directors and lead Design Engineer working on this project with them. So they went out to to the US, to see, to meet with EVOA, and then came back and we obviously started and we went ahead with the project.

JB: And what was the team you had over in the US, Josh?

JS: On our end, we’re relatively lean group. We had myself with the project, and we had a lead design engineer working on the integration, and then we had our manufacturing expert also working with our engineer and myself to make sure that our plans were going to work out when we came over to work with the Williams team, but we were pretty much in constant communication with like the project lead over here at Williams.

Splash mold of stern section sent to USA

They would manage the design on the boat side. We would manage the design on the electrification side. And, you know, just remaining in constant communication to make sure that, you know, the general process of what we did will work out, and that process was we essentially assembled the entire powertrain in our facility in Orlando, because William sent a splash mold of the back section of the boat that allowed us to test fit the motor and work on the linkage with the shaft Going into the jet pump and allowed us to optimize the battery structure and all those things that we did on site in Florida.

Then we shipped that product overseas, and then we were able to integrate almost seamlessly when we got overseas to work with the Williams engineering team.

JB: Okay, let’s break this down a bit and take things one at a time so you figured out the weight and energy storage of the battery. Now, what about placing it in the boat?

JS: The biggest challenge is oftentimes going to be physical space, the engine compartment. And the batteries presented a particularly unique challenge just because of how tight it is to install the system. And we wanted to make sure that in the event that you know you needed to service the batteries, or you needed to service something you know in the boat, you could take the batteries out. So I would say that might have been one of the bigger challenges of designing a battery packaging strategy that one fit, and then two would could be uninstalled if needed.

JB: Okay, and then how about the engine and where that fits in?

TS: The engine compartment in this boat lent itself well to the batteries. The motor itself needed slight structural modifications to the traditional stringer system within the boat. So it was, it was a new mounting system for the motor that went into the boat. So a lot of work on both teams, you know, to one, prepare the boat, and then two to actually mount the motor into the boat.

JB: But in terms of integrating it with the jet drive portion of the motor, yep, I’m assuming that it has been built to whatever fossil fuel motor was working with it.

JS: Yes, yeah. So that’s actually an interesting topic. So edible, we have a couple different, you know, choices from a motor selection to kind of optimize the power curve for.

The application. So this being formerly a diesel jet, the jet on the back of this boat actually pairs extremely well with one of our high torque, low speed motors. So the it’s a direct drive, no gear reduction required.

‘Top 4000 RPM speed matches diesel almost exactly’

The motor world has a top speed of 4000 RPM, which is almost exactly what we were looking at with the diesel. So by simply removing the diesel engine and pairing it with our new motor, there’s like no changes had to be made to the actual jet itself, other than on the evowa side of things, making a shaft to adapt into the jet drive. The speed curve is very similar to the jet drive, and there is a little bit more torque that we can provide. But ultimately, you know, we kind of ramp in the torque to make sure that the performance of the jet is always maintained.

JB: So…it’s the moment of truth. You’re in the UK – Tom, you have testing waters there?

TD: Yes we have a testing lake, which is just outside our facility, just about one kilometer away. It’s about an 80 acre lake. So we can use that for some sort of primary provisional testing.

JB: Were you at the first runs?

TD: I don’t know if I was on the very first one

JB: Well, Josh, you must have been there.

JS: Yeah

JB: Okay, so… you’ve been working on this model in Florida for a few months, and everything looks like it’s planned the way it’s supposed to go, now it needs to go on the water and go into the real boat.

JS: it’s always an exciting time when the product transfers from the shop to the water. I have a lot of confidence in in what we develop. You know, we try and do everything we can to make sure that the product is ready to go to water before we go there.

So there’s plenty of system checks before we hit the water, and those all went flawlessly with this product. And so we went out for that first run, and all things seem to be going smoothly. And I have my laptop out, and I’m checking on everything from a safety perspective, from a functional perspective, everything’s going so flawlessly.

Honing performance on very first test run

TD: We had also a list of a set of criteria to tick off the list, so it was just running through all of that criteria to make sure, as Josh said, you know, temperature and things like that.

JS: And I’m asking Dan, who’s driving, and I’m asking how he feels, and he’s like, Well, I feel maybe we can change the torque profile into this curve, or, you know, maybe make it a little bit less aggressive out of the hole. It’s my favourite part of the commissioning process of a new boat is when you can work with the customer on honing in how you wanted the boat to respond to the driver inputs. And we were actually able to do that on the very first water test you can get from the oh, it works to oh, this is exactly how I want it to work. And that’s always really fun.

JB: And how long did it take you to get to, oh, this is exactly the way I want it to work.

JS: I honestly don’t think it took more than a couple of test runs to get there from like a handling and driveability side of things. After that, we were kind of working through more the minutia of analyzing pump flows and things like that, and we’re able to build a lot of confidence in the product that week before heading out to the proper sea trials over off Southampton.

JB: So Tom coming out of the sea trials, how did you feel?

TD: As Josh said, I think there was, there was some fine tuning, but yeah, we, we managed to achieve a level of performance on top speed which is really important for us. And we’ve achieved a typical activity cycle of 56 minutes, which is only going to get better, I think, as sort of the technology and batteries improve. And we were really happy with that the charge on it as well. We’ve managed to achieve that on the fast charge in under an hour, approximately an hour. So we almost have this one to one ratio. And we quite like that, how that works.

‘Drives like a Williams should’

JB: But as Josh says, with a boat, the driver’s heart is part of it. It can tick off all the things on the spreadsheet, but it has to feel good.

TD: absolutely, and we that’s one of the things which is so important to Williams is that it’s a driver’s boat. Obviously, when you get to a lot of the super yachts, it becomes a crew boat, but the crew are still, you know, driving it, and they’re the ones using it every day for provisions and things like that. So it needs to work as well as it as well as it looks. And one of the reasons we made this a technology demonstrator is because we wanted to make sure that when we do launch something, it drives like a Williams should.

JB: Was there any skepticism from the Williams crew about this electric stuff, or are we kind of past that in the industry?

TD: I don’t know if there was skepticism, but we learn a lot by doing it everything, from the cost of charging on the dock to, you know, the regulation and what’s required to sort of sign it off on the you know, when you’re integrating it into into the parent yacht, there’s so many things which hurdles, which we, you know, didn’t necessarily come think about right at the start of the project.

But I think the biggest challenge is to come in terms of the yacht integration. As soon as we have that, I think there’s a, there’s there’s a ready market for and the customers want it.

JB: So what are some of the challenges in getting electric tenders into the super yacht, big, big yacht market? You mentioned that the customers want it, clients want it.

TD: One of the things from watching us is getting the feedback. There is a willingness and a want to go a bit more sustainable. They want to do it and, you know, zero emissions and things like that. But I’m not a technical person, so I wouldn’t be able to tell you, you know, in detail, but it’s the terms of the fitment, and it’s the charging and how that’s integrated with new technology and insurance, with lithium ion batteries, there’s a bit of regulation to overcome, but, yeah, I think we’ll get there. It’s a matter of time.

JB: And just to wrap things up, you know, what were your your thoughts and your impressions and your your feelings, an awesome price to work with.

JS: WIlliams is an excellent company, and, you know, facilitated the project extremely well. I think the quality of the product speaks for itself. Hopefully a lot of people will want to take a demo ride in and really experience what electric tender can do.

‘When you come into a restaurant or something, the silence is quite epic’

TD: Thank you. And, yeah, you know, the EVOA team have been brilliant. You know, they’ve very much driven this and mastermind a lot of it, and we were happy to be the vessel and collaborate with you on it. And hope, hopefully, you know, going forward, it will stand us both in really good position to do that. So just want to say thanks to the to the availability.

JB: And just one last thing, Tom, you said there wasn’t any skepticism, but was there anything that really surprised you?

TD: I was surprised about just how similar it was to a normal EVOJET. But what you get, which you don’t get with the normal EVOJET, is the silent operation when you’re coming in, you know, to a restaurant or something like that, and it’s quiet. It’s it’s quite a moment. It’s quite epic.

JS: It’s always like, one of my favorite parts is when someone that hasn’t ridden on an electric product before, and then they get on electric boat, and they’re just taken aback on the first time. Like, wait a second, because I can talk to you. We’re not shouting over the engine. It’s, it’s, it’s pretty incredible. And it’s, you know, I think it’s the way boating should be. It just changes the way you enjoy the water, so much.

JB: Our thanks to Tom Dowdell of Williams Jet Tenders and Josh Stoddard of EVOA for giving us the inside scoop on the building of the all-electric Williams EVOJET 70. I Hope you enjoyed this electric boats Podcast. I’m Jeff Butler, editor, publisher of plugboats.com where you can find this story and hundreds of other news stories about the revolutionary world of electric boats and boating, along with buying guides electric boats and motors for sale, supplier directories and more you.

The post Plugboats Podcast: EVOA electrifies the Williams Jet Tender EVOJET appeared first on Plugboats.