Review of SilentJet, Hinckley’s Hybrid Electric Boat Propulsion System

Nearly three decades after the original Hinckley Picnic Boat changed the game, Dasher is back but with all new tricks up her sleeve — it can run in full silence with its trademarked SilentJet technology.

Dash of the Unexpected

Nearly three decades after the original Hinckley Picnic Boat changed the game, Dasher is back but with all new tricks up her sleeve.

A while back, my colleagues and I were talking about what iconic boats from the past we would like to retest for the magazine. Knit-Wits, the first fiberglass Hatteras was a popular choice, as was the first Princess ever built called Project 31. Also landing in the finals was the original Hinckley Picnic Boat Dasher, which we thought might actually be possible since the company had reacquired it a number of years back. Those first two stories haven’t made it to fruition—yet—but I would get my chance behind the helm of Dasher when I least expected it.

I received a cryptic email from Hinckley’s Vice President of Sales and New Product Development, Scott Bryant, one afternoon teasing a new product. When we finally connected on the phone he told me, “We have something really big on our hands and we’d like Power & Motoryacht to be the first to check it out. I can’t tell you what it is, but would you be open to coming to check it out?”

For the record, I loathe surprises. In the deadline-driven world I work in, surprises are almost always bad. But Bryant’s energy was infectious, and he’d earned my trust through our previous waterborne adventures. He had yet to oversell me on a new boat from the brand. Even when they launched the all-electric Hinckley Dasher or their first outboard-powered sport boats, he had been enthusiastic but also even keeled.

Photo: John V. Turner

“I’m going to go ahead and trust you on this one,” I replied. “I’ll see you next week.” I said a silent prayer to Poseidon that I wasn’t heading to their Rhode Island office to bear witness to the latest and greatest in windshield wiper tech.

Anticipation built as Digital Director John Turner and I made our way to their Portsmouth facility to peel back the curtain. Along the way we ventured guesses as to what the surprise might be, each guess getting more radical. A Hinckley sportfisherman? A Hinckley superyacht? A submarine complete with teak and holly floors? Foils? Electric? Autonomous? A foiling, electric, autonomous sportfisherman with teak and holly floors? Did I mention I hate surprises?

We met Bryant at the Hinckley compound. I’d already been peeping around the marina on our way into the yard like a youngster trying to catch a glimpse at his Christmas presents, and I expected he would walk us down to the docks. Instead, he immediately led us to a conference room. The only thing I hate more than surprises are conference rooms, and Bryant again had me praying this news would live up to the hype.

Bryant asked if we remembered the all-electric Dasher project. Of course we did. The Newport unveiling and subsequent Florida test left such a favorable impression on the Power & Motoryacht team that the boat landed on the cover of a previous technology-themed issue.

Power & Motoryacht January 2018 Cover

“The boat did a lot of really incredible things where the client didn’t have to think about how far he was going or his range and all that, because it really tracked everything for him on the boat,” said Bryant. “It gave him a very intuitive interface to show him all those things. What we also demonstrated were the benefits of electric propulsion. And what we learned in that process is that people love the silent running aspect where you could get on the boat, you didn’t have the sound or the smell of diesel engines, you just had this quiet whir, so to speak, that was happening below the waterline.”

Aha, so it is something electric, I thought to myself.

Bryant explained that more than any other aspect of the Dasher project, it wasn’t the impressive speed, the intuitive range interface, the fuel savings or even the boat’s environmental friendliness that people appreciated most. What really appealed to boaters on sea trials was how quiet the boat was. The boat’s range, on the other hand, left something to be desired.

“So, we started working on a project that addressed both of those needs: silent running and long range,” said Bryant. “But how do we do that? How do we have the best of both worlds?”

He went on to explain that the company teamed up with transmission experts Twin Disc to collaborate on a hybrid electric system called SilentJet that would switch seamlessly and automatically from diesel to electric power depending on how much throttle you’re using.

He gave us a first look at a video that shows a hybrid system that can be charged from the running diesel engine as well as shore power. Bryant claimed the system would offer high-performance diesel power when you’re ready to go fast, far and silent and electric propulsion when taking your guests on a sunset cruise.

“We partnered with Twin Disc on the SilentJet technology so that we could create this really incredible experience on our Picnic Boat,” he said. “The beauty of SilentJet is that all of the thought process is done for you. So, when you leave the marina under electric power and silence—as soon as it’s time to go somewhere, automatically you put throttles down and the diesel comes to life and carries you to your next destination while also charging the battery. When you get to your final destination, you drop the anchor and everything runs on that battery.”

“Back in 1994, when we introduced the first Hinckley Picnic Boat with a joystick, that was pretty revolutionary for the time. And that first boat, it kind of had a slow take up, but the first time we took it to the Newport Boat Show, it just started the revolution and that was it. People loved the Picnic Boat. They loved the ease of use, the joystick control. And so, that first boat, the name of that boat, was believe it or not…”

Dasher.” I replied.

“That’s right,” he said. “[The first picnic boat was named] Dasher. Well, about five years ago [that boat] came to market, and we bought it. We’ve had Dasher in the stable for a couple of years. We needed the best possible test boat to develop SilentJet on. So, we raised Dasher out of the shed and we repowered her. We put this new system inside of her to really test SilentJet and also to be able to take folks like yourself out for an experience.”

We finally made our way down to the docks where one after another, beautifully maintained Hinckleys glistened under the summer sun. And there, hiding in plain sight, was the celebrity herself—the original 36-foot Dasher, aging like a single malt scotch in a teak cask. It takes only a little imagination to picture guests of the ‘94 Newport show ditching their Sperrys for a chance to clamber aboard the sleek vessel.

Her recent heart transplant includes a re-powering with a 570-hp FPT Industrial N67 570 diesel paired to the proprietary Twin Disc Hybrid System (comprised of a transmission and electric motor) and then mated to a Hamilton jet drive. We climbed aboard and Bryant fired up the 12.9-liter engine. Dasher’s bones reverberated as jet wash stirred to the surface. Scott pushed the throttles ahead to keep the boat in diesel mode. Then, for the big party trick, Bryant eased back on the rpm. It takes a second or two to feel the engine shut off and then you hear, well … nothing. Compared to other hybrid-powered boats I’ve been on there is no hum, whine or cavitation from props.

Photo: John V. Turner

Losing the lines, we glided out of the crowded marina aided by the peace of mind joystick maneuverability engenders and set out onto Narragansett Bay. Getting my turn behind the helm, I found it hard to believe that this Dasher was approaching her third decade; clearly, she’d taken care of herself better than I had in my twenties.

At first, I have to admit, pulling back on the throttles and engaging electric mode felt like the boat had stalled—don’t ask me how I know what that feels like. But you quickly get over that sensation, and in short order I had total admiration of how seamlessly the system shifted from diesel to electric.

The second half of that party trick was that while we were blasting around in diesel mode, the batteries were being charged at an impressive rate. According to Bryant, just 30 to 60 minutes of cruising in diesel mode is enough to fully recharge the batteries and eliminate the need for the added complexity of an onboard generator.

To really run home how well the boat operates and cruises off the battery bank, the Hinckley team invited along chef Chad Hoffer to prepare an incredible lunch of halibut porter houses. Without a garnish of exaggeration, Hoffer, who works at Newport’s esteemed Thames Street Kitchen, prepared the best seafood meal I’ve ever had. It was a taste of the Hinckley lifestyle, and one I hope to savor again next time I’m in The City by the Sea.

The next phase of the SilentJet rollout will be implementing the system on the brand’s modern iteration of Dasher in the Picnic Boat 40 S, with a pair of 90-kW electric motors, a 80-kWh battery and twin 550-hp Cummins. Hinckley is predicting that at 7 knots, the 40 S will be able to cruise for an hour and reach 35 knots in diesel mode. The best of both worlds? It just might be. I guess surprises aren’t so bad after all.

This article originally appeared in the October 2022 issue of Power & Motoryacht magazine.