Taking Shape

A scale model of the transportable trawler takes shape at Mirage Manufacturing. The process begins with sophisticated computer modeling, but also requires some skilled, hands-on craftsmanship

By Travis Fickett

My father has an almost uncanny ability to visualize objects in three dimensions, and he uses this to his advantage to come up with new designs and create intricate molded parts. He just seems to know how things will fit together, before they are even built. I'd like to think I share some of those talents, but I also take advantages of the tools of the 21st century such as Computer Aided Design, or CAD.

​When I was given the first sketches of the tranportable trawler, I redrew the profile and plan views in Rhinoceros 3D, one of the most widely used surface modeling applications. Using Rhino, I can load and tweak specific parameters such as length, beam, and height to start the process of translating the design to the third dimension.

Rhino allows you to create a realistic rendering that can be rotated in any direction. This really helps visualize the final product, but that's just the beginning. I can use the program to see how things might fit together—or might not. For example, after creating a bow profile, I can move inside to determine if the foredeck height provides sufficient headroom in the forward stateroom. If not, modifications can be made with a few simple mouse clicks.

Fleshing out the 3D model involves thousands of these types of checks and tweaks. And as we home in on a final design, modeling provides yet another invaluable resource in the ability to calculate surface areas. This becomes especially important if you are working on a project that is weight sensitive.

One of the primary design parameters of this new boat was to create a final product that would weigh less than 6,000 to 6,500 pounds dry. We are confident we can hit this goal, as we have a lot of experience in cored construction techniques. My father was one of the pioneers of cored construction in the marine industry. He has been producing high-performance sailboats, sport fishing boats and light aircraft for more than 45 years, and knows how to create laminates that are light, strong and durable.

The running surfaces of the trailerable trawler take shape in the Rhinoceros 3D suface modeling program

This gave me a tremendous advantage when it came time to do predictive modeling on the weight of the new boat. We laid up some material samples using the appropriate resins and coring materials, and determined the weight of these laminates on a square-foot basis. Using Rhino, I was then able to calculate the total surface area of the hull and topsides, plug in the weights and produce an accurate estimate. My target number is 2,000 pounds for the hull and superstructure. Based on the latest round of calculations, it looks like we can hit these numbers.

The other interesting thing that the CAD process helps visualize is the boat's running surfaces. This new model will be a radical departure from anything we've done before, as it taps into some very advanced hydrodynamic concepts. The bow has an extremely fine entry and a tall profile, with only the slightest flair above the waterline. Hard chines carry all the way aft, and the running surfaces taper to a 5 degree deadrise at the transom. This design should create significant lift, and minimal bow and stern waves. It is expected to operate efficiently at speeds between 10 and 15 knots without having to climb over the “hump” that plagues so-called “semi displacement” hull designs. We also expect it to perform well at higher speeds, as we know some owners may want the option of larger engines and speeds above 20 knots.

Above the hull/deck junction, there is an equally subtle tumblehome, which is not just a styling element. We plan to incorporate a substantial rub rail at this junction, which will be the widest point of the boat. Fenders are always a good idea when docking, but on this boat, you could pivot the bow against a piling without scuffing the gelcoat.

A computer simulation of the trailerable trawler shows the hull's fine forward entry and dimensions of the low-profile deck house

​With these general design parameters solidified, the next step was creating a physical model, and once again the CAD software proved useful. Essentially, it allowed me to cut the boat into virtual cross sections, creating profile dimensions that are known as stations to boat builders. Working with these profiles, our in-house design team constructed a 12th scale physical model of the hull, then added basic details of the deck and topside. As I am writing this, the finished creation is going north to the Annapolis boat to be revealed to the boating public.

The completed model

​There will be some tweaks to the design made as we move forward, based on what we learn in development, and on feedback from the public. So far, this has been one of the most highly-anticipated new projects we have ever undertaken, and we've been impressed by the enthusiasm of those following the creative process. We are equally excited here at the factory, There's a sense that we are not just creating a new model, we are defining a new category of cruising boat.