Meeting deadlines is important in any business, but it seems particularly so when it comes to creating composite parts. Especially when the parts are needed in order for a 70-foot trimaran to compete in the Nassau Cup Ocean Race in less than three months.

Oliver Moore says that they were approached around the middle of August by Argo’s captain to change the shape of the tips of each foil in order to up the boat’s speed average. The foils were originally designed by VPLP Design– the French design company– and built by AVEL Robotics SAS. The plan was to cut the lifting tips off each foil, make new ones to a new design and reattach them.

Simple, right?

All Moore Brothers Co. needed were the new designs from VPLP for the tips and they could get started.

There was just one problem. It was August.

Most French residents go on vacation in August. “We were having calls with the designer from his vacation on a boat in the Med,’ says Oliver with a laugh. It took some back-and-forth for both sides to come to an agreed upon build approach. The Moore brothers needed to be certain that they could both execute the project, as well as ensure that the foils were structurally adequate and could withstand the conditions that they would be up against.

“We came to a compromise,” says Oliver. “We started with needing a 10 millimeter deep scarfing laminate on the outside that would go across the seam,” he continues. “But it took some thinking about how we were going to connect the remaining 60mm of spar in the middle nicely.” They finally settled on a 200mm ”bird’s beak” tenon between the existing spar and the new tip.

Moore Brothers Co. didn’t get the final designs until the first week in September and started machining parts on September 8th.

Now, the race was only two months away.

Were they nervous to get this done in time? “Oh yes,” says Oliver. “I think the level of skepticism from the rest of the shop was significant,” he continues, but he does point out that the most skeptical of the crew were the ones that were doing overtime to make the deadline.

Moore Brothers Co. has worked with Argo for years, but this project was definitely one that was pushing the limits of the company. “A lot came together to make this happen,” says Oliver.

Next up in the design process was to decide how to build the new tip. “You canmold up both sides, figure out how to make and cure those halves and then glue them together,” says Oliver, “but you have to figure out how to make the mating surface perfect, and you end up with a secondary glue bond that is difficult to control the thickness of, which is critical.” he continues.

Or you do it another way.

“We like to call it the open face sandwich approach.” Says Oliver, “you mold one side and build the foil up beyond where it needs to be, then go back and shape the other side of the foil with a CNC machine.” This reduces the bondline control issues and reduces the tooling needs.

The principal issue with this technique is you have to put the foil back into the CNC machine multiple times. “The problem with prepreg is you need to get things hot and the various materials all change shape depending upon their different properties,” says Oliver. “If you put it back on the CNC machine, and the machine doesn't know that the thing has changed shape,” he continues “now you have lost your accuracy.”

So the key is stable carbon fiber tooling. The traditional method is to make a plug and a carbon tool from the plug. The problem comes with then getting the structure on the tool perfectly such that when you turn it over and put it back on the machine the tool surface is exactly where the machine thinks it should be. “We applied the same open-faced sandwich technique to the tool. We molded the back side of the mold, added structure and then direct machined the final tool surface.”

They could have used high-temperature tooling foam, but it is expensive, has availability problems and large volumes of it can split if not processed very carefully. “We have had issues with the tooling foam in the past so we came up with this technique of direct machining a carbon tool using recycled carbon felt,” he says.

Around the same time that they had gotten the Argo job, Moore Brothers Co. had bought a ply cutting machine, allowing them to 2D cut prepreg carbon in complicated shapes. “What you can do is you can take your solid shape you're trying to make and you break it up into slices in design software and then turn it into a contour map,” Oliver says. “Then you take those shapes, lay them out flat and each ply of material is turned into this 2D shape. “You end up with a lot of them.” He continues.

The ply cutting machine then creates stacks of material which the Moore Brothers Co. crew then laid out in the mold, building layer upon layer.

“It takes all of the guesswork out of the lamination process,” Oliver says. Basically, it makes the lamination process more of an assembly job. “Which ultimately makes it more efficient,” Oliver says.

Each part went through two lamination cures and 4 rounds of CNC machining. The first half of the laminate was cured and then one side of the mortise was machined, a plant was added, the top of which was then machined to the other side of the mortise. The second half of the laminate was cured over the plant, machined foam was added around the solid carbon spar and then the tension side surface was machined with reductions and rebates for the scarfing laminate and skin.

“All of that is a hard thing to do,” says Oliver. “And our ability to do that nicely was predicated on us getting that ply-cutting machine, and our stable tool. We were machining the peel ply texture off of the part.” he continues.

As far as having experience with the ply-cutting tool, everyone kind of learned on the job. According to Oliver, it was similar enough to the CNC routers to figure out quite quickly.

“This is a good example of using our in-house design capacity.” Says Oliver. “We were able to design the whole process using our machines and accuracy so that the assembly time of the actual part was really efficient.” He continues. “Mark Raymond led the design effort and when he took his already scheduled, but unfortunately timed vacation, Simon Day stepped up to the plate and I jumped in to help with machining the existing parts.”

While they were building the tips they had to machine the existing struts precisely to mate with the new parts. So they designed a custom fixture to hold the existing parts and machined the tenon and scarfing laminate rebate into the solid carbon spar.

Another fixture was then designed and built to hold the two parts accurately together while they were bonded.

Another round of ply cut laminate followed making up the scarfing laminate and the tension side skin. Each step along the way was checked for defects by Alex Wadson using phased array ultrasound NDT. The team has Alex check all their structural components after each event and this allowed him to build a comprehensive baseline to compare to in the future should any issues arise.

Kenny Madeiro and Sean Lane put the first plies in a mold on Friday September 23rd and 3 weeks later the last vacuum bag came off on Friday morning, October 14th. They were painted over the weekend with help from Argo’s crew members as well as the Itchiban crew.

Six weeks after the start of tooling the foils were in the boat the following Monday and they were sailing with them on Tuesday.

“A lot of stuff came together to make it happen,” says Oliver. On November 4th, ARGO set sail from Miami and crossed the finish line in Nassau with a time of 09:03:01, beating the previous record for that race of 13:31:30 set in 2012. Safe to say, the foils worked.