The Triton


Yacht repower like a heart transplant


When a megayacht needs a new engine, it is nothing like opening an automobile hood to install a new one. It’s a big job that often entails cutting a car-sized hole in the hull.

Aaron Beiswenger said it can be complex. Beiswenger has worked on many yacht repowers as a naval architect with Murray and Associates in Ft. Lauderdale, including work with Capt. Doug Coe on M/Y Hilarium, a 137-foot Hakvoort.

“Basically it’s like a heart transplant,” Beiswenger said, pointing to a photo of Hilarium’s original engine, the heart, hanging from straps during a recent repower at Derecktor in Dania Beach, Fla. At this point in the repower, the yacht sat on the hard with a 7-square-foot hole in the side and new engines waiting in containers in the yard.

Removing the old engines was just a fraction of the project. Like an organ transplant with blood vessels and nerves, an engine’s fuel, intake, exhaust and electric have to be cautiously reconnected.

“What I run across a lot of the time, is that the captain is surprised by the complication,” Beiswenger said.

Plan ahead

Problem prevention is the best way to approach a repower, and that is done with planning, organization and communication.

“If you let a problem snowball and get away from you, you can’t get it back,” Coe said by phone from Hilarium in Italy.

Coe and Beiswenger agreed that planning is key.

“Doug [Coe] prepped, planned and scheduled the yacht to be in the yard four months ahead,” Beiswenger said of the Hilarium job. “That worked well for contractors to become familiar with the vessel. It was quite impressive. I give him credit. Too many times, captains are not prepared.”

As with a successful surgery, the tools and parts need to be on site, and the workspace ready with crew in place.

“Captains would be wise to spend more time planning things out,” Beiswenger said. “They can do their homework by finding boats that have done similar work or yards that have done it. And prepare for downtime.”

Some captains prepare with a program such as a Gantt scheduler program, which uses bar graphs to organize start and finish dates for everything from ordering parts to managing contractors.

Meet head on

Meetings are also key, according to the chief officer of a large yacht that recently repowered in Ft. Lauderdale. The officer and captain asked that the vessel not be named.

“The key to the success here was scheduling and project management with daily meetings and a weekly schedule review,” the chief officer said.

On Hilarium, Coe also held a Friday wrap-up to decide if extra work was required on Saturdays. A  wax pencil board at the job entrance was another tool he used to keep crews informed of deadlines and expectations.

“Say the guy comes to sweep and clean up but sees that they are going to paint, so he can’t,” Coe said. “He can explain that he hasn’t cleaned in a while, but needs to. That way I can delay the painting for a couple of hours.”

First things first

Choosing new engines is one of the first orders of business. Beiswenger recommends an engine be ordered about 10 months ahead because it can take six months to build. The naval architect analyzes compatibility including how the new engine footprint will fit on the current engine beds and how to connect components such as the gearbox, generator, exhaust and seawater connections.

He works with the captain and owner to pick the right engine, whether the goal is more power or to save fuel. Beiswenger uses programs such as NavCad to predict and analyze speed and performance and to test resistance of each option. Naval architects may request to go on a sea trial first to understand what is needed for efficiency and speed.

“It’s helpful if the captain brings as much as possible on original build plans,” Beiswenger said. “We can get specifics from the manufacturer, but the history of the yacht’s rebuilds helps.”

Price is not always the best bargain for a new engine, he said.

“It is rare for best fit engine to also be on sale,” Beiswenger said. “Consider the cost of the engine is just a percentage of the project. If you get it 20 percent cheaper, but the footprint is different, you will probably spend the amount you saved. Anything that you have to move equates to money.”

With downtime in the yard, many yachts tend to also include maintenance, repairs and warranty work.

“Since it’s a fairly major expense, we want people to think of what else can be done at that time,” Beiswenger said.

Coe did.

“While the engine was out, we refurbished the air conditioning and accessed parts of the engine room we never have gotten to before,” Coe said.

As to a ballpark cost? It varies with complexity, but for an initial estimate, expect the cost of the engine plus that amount again, Beiswenger said.

The hole story

Now just how to pull out the old and bring in the new engine? To make the decision Beiswenger prefers a site visit and uses 3D programs to model options. If a hole is cut, the goal is to find the fewest pipes, electrical wires and structure to disrupt. Usually the cut is through the side on metal boats and through the deck on fiberglass.

“Sometimes we can come in through the salon and sometimes it is advantageous to enter on the bottom to save the paint job,” Beiswenger said.

Cuts often have to be made because builders do not take a repower into consideration and usually don’t leave a soft patch, like a hatch or an area that can be easily accessed. Cut location is based on things like how the hole will be sealed. And even though contractors use a fine saw to cleanly replace the cut-out, replacing, fairing and painting can take a month.

Deliberation on where to cut the hole affects all subsequent decisions and was taken seriously by Coe and his team.

“Believe me, when is was being looked at, it was almost down to the toss of a coin,” he said. “But then we thought it over more and picked the least intrusive, most sensible choice, the side where we wanted to make improvements.”

Typically the access hole is not cut into the yacht until the new engines are on site. The hole is cut as small as possible and engines are moved in and out sideways because they are longer than they are wide, Beiswenger said. It is an option to disassemble engines but most yachts try to avoid that.

Reconnecting the new engine usually entails changes and the engineer usually organizes how things should go back together.

“The engineer is very important and we prefer he make some decisions because he is the one using it,” Beiswenger said.

The engineer was in charge of all day-to-day on-scene operations on M/Y Hilarium.

“He, in the end, has to understand and operate what we have done,” Coe said.

Hilarium’s engines were 30 years old and the reconnections demanded skilled “surgeons” to move the new engine’s raw water pickups from the front to the back. This required all new copper nickel welded raw water plumbing and engine bed modifications to accommodate the new engines’ footprints. Plus 135 feet of cable was run from the engine to the wheelhouse.

Sweat the small stuff

Depending on a repower’s complexity, there are a few topics that most yachts should consider:

● The yacht’s insurance company will want to know about the work and Shipyard Repair Legal Liability (SRLL) may be required for contractors, damage liability, equipment, security and fire protection (if hot work is involved).

● Scaffold and tents are usually required to protect the yachts from weather and yard dust, said Dockmaster John Terrill of Lauderdale Marine Center in Ft. Lauderdale. Placement can take a week or two.

“It is important because most yachts don’t have a soft patch in the salon floor so they may sit for months with open holes,” Terrill said.

Depending on how the project is accessed, the crew may need to remove furniture, clear out cabinets and store items. Valuables and doorways may need to be covered and protected.

● If the yacht is in a class, it may be important to get approval for changes along the way. Even if a modification seems simple, such as changing a water line, the class society may mandate the materials used, the angle of the bend, etc., and it may take weeks for approval.

In the end, although planning, organization and communication are key, Coe said it was important to make the best of a difficult project and work together.

“It’s supposed to be fun, and I want people to take pride in the project,” he said. “I don’t want them down at Waxy’s having a beer and complaining. Instead, I hope they’re talking about their ideas and what they want to do at work tomorrow.

“It’s many leaders all working together; no one person gets the single credit for the job,” Coe said. “I am only, after all, the bus driver. The main thing it takes is teamwork. That, and good coffee. A ton of it.”

Dorie Cox is associate editor of The Triton. Comments on this story are welcome at

About Dorie Cox

Dorie Cox is editor of The Triton.

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