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.
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.
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.
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.
One for The Road
Work on our new “transportable trawler” is underway
Maybe it was the recession, or maybe folks just got tired of owning and maintaining so much stuff. Whatever the reason, the concept of “downsizing” has taken hold in recent years, giving rise to such concepts as the “tiny house” movement. In the nautical realm, this has resulted in a newfound popularity for the so-called “trailer trawler,” a compact cruising boat that can be easily transported over the road, while also providing at least the basic creature comforts needed to live aboard.
A number of our customers have expressed interest these boats. But after being spoiled by the home-like amenities of the GH trawlers, they weren't quite ready to sleep on boat-cushion bunks, cook on built-in camp stoves and resort to portable toilets, which is the level of amenities you'll find on many of these pocket yachts. “Build us a transportable trawler that you can actually live aboard,” became an increasingly common request. A number of designers and builders have taken a stab at this concept, but after studying what is out there, we could find few that hit that “sweet spot” between big enough for comfort and too big for easy and economical overland transport.
We started to jot down a wish list of our own. We first decided that, though the boat would be designed for trailering, keeping to a standard 102-inch beam would be too restrictive. So instead we decided to keep it within the limits of the standard blanket permit for wide loads. This would allow owners to transport the vessel themselves with minimal paperwork and no special licenses, or to hire cost-effective towing services rather than contracting a big rig with a flatbed and hiring a crane to load and unload. Setting the max beam at a bit under 10 feet allowed for a well-proportioned hull in the 35 foot range, with plenty of living space.
The next consideration was weight. We'd looked at several trailerable trawlers in the 30-foot range that came in at well over 10,000 pounds—and that's before taking trailer weight into account. Moving that much mass around requires a very substantial tow rig, and demands a lot more skill on the part of the driver. To lighten things up, we decided to build the entire boat using composite cores. Our target was a 6,000 pound final product, which is achievable when using modern materials and methods. Another key to weight reduction would be the use of outboards rather than an inboard diesel engine. Modern outboard are extremely reliable, economical and quiet. They are also far less complicated to install, and hanging them on the transom frees up a lot of interior volume for other purposes.
Unlike our larger trawlers, which are strictly displacement speed vessels, we wanted a boat that could run at least into the mid teens, while still delivering good fuel economy. This lead to a hull design with a moderate aft deadrise for lift, and a very fine forward entry to cut through seas with minimal effort. Above the waterline, we decided to go for a classic look. The resulting first-blush profile is something we think papa Hemingway would have been proud to own.
By early September of this year, we've translated that first sketch into a computer-model, and are now able to begin the process of tweaking, measuring and forecasting that will lead up to the fabrication of a scale model, then full-sized molds. It's still early in the game, with a lot of details to be ironed out, but we can offer a few key points that we feel confident will make it through the design and build process.
Count on sleeping on a real mattress in an adult-sized bed. Expect a spacious bathroom with a shower that's large enough to actually use. Plan for a home-style galley with real appliances, and a social area spacious enough to entertain guest or provide realistic sleeping for children or a second couple. You'll be able to walk safely around the side decks, enter the boat comfortably from docks at any height from water level to six feet, and have plenty of room on the cabin top to mount a tender, kayaks and solar panels. Based on initial calculations, a pair of 60 hp four-stroke outboards should move this boat at cruising speeds in the 14 mph range, and it will handle larger engines and higher speeds for those so desiring. There’s plenty of room in the bilges to include a generator, A/C and heat, a water maker and more.
At the factory, we're getting pretty excited about this boat, because it could be a game changer. Here's a reasonably-priced cruiser that you could take into really skinny water, or head offshore and cruise to the islands. Putting it on the hard is as easy as backing a trailer down the ramp, and you could move it from Miami to Seattle in a matter of days. If you really want to get adventurous, put it on a roll-on cargo ship and take it over to Europe to explore the French canals or cruise the Med. For most of us, this is really all the boat you'd ever need to make your cruising dreams come true. Stay tuned for more details.
By Ken Fickett
Ken is the founder of Mirage Manufacturing,