Fiberglass was a revelation for the boating industry. Prior to this, boats were made of wood, metal, or ferrocement. All had drawbacks. Metal rusts; wood rots and leaks; and ferrocement is tricky to work with (and suffers from an unfair reputation in the States, affecting resale value).
Fiberglass is basically a woven mat of plastics and glass fibers, combined with a resin or hardening agent. While it can develop blisters, and if improperly constructed can take on water through its outer skin, fiberglass quickly became the standard material for recreational boating due to the cost, weight, strength, and ease of construction. Since it conforms to any mold, boat builders were able to make hulls with sweeping curves and fewer of the joints found on wooden boats and sharp angles found on steel and aluminum boats. It’s also easy to repair fiberglass.
Fiberglass does have its drawbacks. It can be messy to work with. My last boat had delamination issues in the deck, which meant cutting away the headliner in the bow, digging out all the rotted balsa core, and laying up new glass to strengthen the deck. It was only one of many ugly projects with fiberglass over the years. The resin gets all over you, smells awful (you need to wear a mask while working with it), and the rove and matting material is itchy like fiberglass insulation. You’re basically getting cut up in thousands of microscopic ways.
Even worse, you have to use a lot of resin to make sure you soak all the matting, and you never get it completely soaked. While cutting through glass over the years, I’ve often run into dry matting that never saw a touch of resin. That’s a weak spot. In other places, resin is pooled, and this excess is both waste and extra weight—resin provides little strength on its own.
Enter vacuum infusion, a relatively new process employed by many of the top boat builders today. It’s how Wayfinder’s hull is being built. Here are some pics of the process in action, with my amature commentary sprinkled in.
Here you can see the dry fiberglass material laid up in the female hull mold. The entire hull of the catamaran (you’re only seeing the starboard hull here) as well as the deck that bridges them together, is laid up in a single mold. So there are no joints. This makes for a very strong construction. Not many large cat builders today are doing resin infusion and 2-piece construction like this. It’s one of the reasons the St. Francis 50 is both strong and light (which means both safe and swift).
You can see the pocket for the keel up there. This will become the black water holding tank (where the toilets pump). You can also see the new portholes up there, as well as the large fixed window in the aft stateroom.
Here we see the tangle of hoses that will be laid out on the dry mat and roving. With resin-infusion (or vacuum resin infusion, more properly), these delivery lines are laid out across the laid-up fibrous material. Rather than brush the fiberglass onto the material (resulting in poor penetration) or soaking the matting and laying it up wet (resulting in poor penetration or, more often, too much resin), with vacuum infusion, the resin is sucked into the fiberglass using a low-pressure environment.
Here you can see the bagging that goes down on top of the delivery lines. This bagging allows a partial seal to be made, so the vacuum pumps can create a low-pressure environment. When the resin is pumped in, the vacuum will try to equalize through the matting, pulling the resin all the way through the fibrous material. This ensures complete saturation of the material.
The entire hull has been prepped with hose and bagged. This is a great shot of the deck spanning the two hulls. That will be my living room (saloon), directly in front of the gentleman standing in the starboard hull. The raised portion closer to the camera will be the cockpit. And just forward of the saloon will be the master cabin (with the VIP cabin on the opposite side). Crazy to think that this is my future home.
Okay, they’ve started the flow. A good time to mention the other advantage of vacuum infusion. So I mentioned how much stronger these hulls are, because the resin flows through the entire material. Well, it’s also a lighter construction as well, because any excess resin is sucked out the other side. As you can imagine, this process is healthier for the workers and better for the environment, with fewer risks of contamination.
A great shot of the flow of resin. The dark orange areas are where the resin has already penetrated. It’s flowing outward from the grid of blue hoses. You can see two containers sitting on either side of the deck, distributing the resin under vacuum pressure.
This photo is a thing of beauty. The man on the right is standing close to the end of the galley. The other man is kneeling about where the sink will be (just aft of him). The neatness of the resin infusion process is just lovely.
Here’s the fully infused hull. The resin will harden, and a releasing agent will allow the fiberglass to pop out of the mold. At this point, the boat will have two main pieces: the hull and the deck. This creates the only major joint in the boat, which is high above the waterline and severely reinforced for strength. By the time I arrive in South Africa, in the middle of April, the deck and hull should be paired to one another, and the subfloor will probably be in. At this point, I’ll be able to walk through my new home, helping with the layout and last few details. Pretty soon, this baby will be out on the water, infecting me with smiles.
2 replies to “Wayfinder Build: Part 3 – Infusion”
I knew of a bloke who had a ferrocement boat (I just read that back and it sounds like the start of a limerick!). He had a collision with a steel-hulled tug on the way into harbour in Gibraltar and came out of it barely afloat. The insurance company didn’t have a clue what the value of his boat was, so they settled for the equivalent cost of repair to a similar-sized fibreglass yacht. He couldn’t believe his luck – he nipped down to the DIY store for a few bags of ready-mix, did the repairs himself and netted about twenty grand profit!
They are great boats. I’ve known a lot of sailors over the years on them, and the construction is sound. You just have to be careful when building them.
They have a better reputation overseas. In the US, we think of them as construction material, or rocks, and rocks sink. So they don’t get purchased, and they don’t sell well.