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By Ed Fry
FRY Associates, Inc. (FRYCO)

Why a custom design?

Every major yachting center has dealerships and marinas full of new boats and brokers that list thousands of existing yachts. So why have a custom yacht designed? There doesn't seem to be any singular answer to that question. In the case of yachts up to 100 ft. (30m) there are many very good production yachts on the market, still some people find, for various reasons, that available yachts don't quite suit their requirements. Perhaps they are not fast enough, perhaps the client is not satisfied with the styling or the arrangement or the builder’s quality, the list goes on.

For larger yachts there simply isn't a production equivalent. Most people who have a custom yacht designed have owned several yachts, know exactly what they want, and for some reason have not been able to find the "right yacht" in the marketplace. To most owners a yacht is a very personal thing and they want one that is arranged and laid out according to their lifestyle and that is equipped to do the kind of yachting that they like to do whether it is sportfishing, long range cruising, fast boating, sailing or just houseboating the ditch.

Today we find a new generation of boaters that want speed. Sportfishing yachts are faster because they are fishing further away from home and they want to get out and back to win that trophy or prize money. Likewise yachtsmen are not satisfied to putt long at 20 knots, so fast boats are the order of the day.

Other clients don't know what they want so they hire an experienced custom yacht designer to help guide them. These are the clients that challenge the naval architect to do something different, unusual or better.

Just how do you go about designing a yacht?

No matter how much experience you have or how many times you have gone through the cycle, it always starts with spending time with the client to find out exactly what is wanted and then developing what can best be called "the owner's requirements". This information tells the designer approximately what size yacht is desired. Whether it is for high-speed or long-range, whether the owner cruises alone, or normally has guests, whether the yacht is to be used in protected waters or full ocean cruising. We learn about the owner's equipment preferences, principal activities, such as fishing, racing, cruising, or other water sports. With this information the naval architect can develop a set of principal characteristics and begin to come up with an envelope to fit these owner requirements. Next the designer needs to know the owner's styling preference, avant-garde, traditional, or just modern. Usually four or five profile and arrangement plans are developed and discussed in detail with the client to firm up his ideas and to give him options to trade off living space versus sleeping quarters, speed versus range, etc.

After the owner requirements are defined, the serious work of design begins. The hull form is developed and studied, multiple powering options are considered, equipment lists are developed and electrical load analyses are made. At this time the basic hull structure can be designed and developed. Next comes the writing of a complete set of specifications which along with the drawings and other details are submitted to the owner for his final stamp of approval.

A yard is then selected to build the yacht and the naval architect works with the yard's engineering department to develop all of the detailed shop drawings required to build the finished yacht. During this phase the naval architect represents the owner to be sure the fabrication is sound and that certified materials are used. He checks equipment to verify it is installed in a manner which will result in a yacht that needs a minimum amount of maintenance. At the same time he is working with the owner (or interior designer) and the yard to select interior fabrics, furniture design, floor coverings, ceilings, lights, bath fixtures, galley equipment and literally thousands of small detail items.

Usually when the yacht is finished, the naval architect supervises the sea trials before the yacht is handed over to the owner.

How are computers used on yacht design?

Today computers are the tool of the trade, just like drawing boards and drafting instruments were in past times. They allow the naval architect to handle a voluminous amount of data in a very efficient way. Computers make some parts of the design process easier; however, they do not replace the artistic eye and experience of the designer. After the approximate size of the yacht has been determined and the mission profile studied so that the desired speed and range are known, the computer is used to predict the resistance so that the horsepower can be determined to select engine(s). Computer modeling lets the naval architect have the freedom to enter design parameters and to vary widths, weights, bottom angle for best results. In a matter of minutes the computer calculates very accurate and useful data to help determine the hull shape and powering requirements.

The 3d modeling programs that have been developed in recent years are very advance and allow the designer to illustrate the yacht’s styling, rotate to any angle and color as desired.  They allow exact fit of the interior and systems saving a large percentage of the time required for construction.  With few exceptions all of the industry uses one of these programs to develop the basic and production designs. 

Next the computer is used to develop hull lines and to fair those lines to very small tolerances. The accuracy is greater than necessary; however, it gives the builder exacting information from which he can establish his own tolerance. Fiberglass molds made from computer lofting require less time and provide fairer surfaces than pencil drawings where the builder can be off by as much as 1/8th of an inch just by measuring to the wrong side of a pencil line. In metal boatbuilding the computer numbers are often fed directly from the computer to the shipyard computer program where the steel or aluminum plate is cut from the numbers thus eliminating any need for costly and time consuming full size hand layout of frames and plates. In composite construction, plugs and molds can be digitally cut using 3-D shaper cutting machines.

After the lines have been put into the computer, the naval architect has all the hydrostatic calculations displayed in front of him in seconds. He knows the displacement of the yacht, the center of buoyancy, the pounds per inch of immersion, prismatic coefficient and other important data. As the designer makes minor adjustments to the lines, the computer recalculates all of the hydrostatics instantly.

When building to class or USCG approved Charter Yacht, the hydrostatics must meet strict guidelines and computer models are created to simulate various conditions of loading and creating damage conditions according to the possibilities allowed by the hull subdivision. This very important function is all too often forgotten by builders and on occasion by designers that are not familiar with the established practices for safe construction. Due to this negligence many yachts have been lost, some on their maiden voyages.

Later in the cycle, the propeller design or propulsion system design is determined by special computer programs developed specifically for the type of vessel being designed.

What is model testing and what does that do for you?

Model testing is the physical towing of a scale model of the exact hull shape of the proposed yacht, through a water tank with a fully instrumented carriage that measures the motion and resistance of the scale model hull. This data is then translated to give a very accurate prediction of how the actual yacht will handle and precisely what hull drag can be expected.

One should also conduct rough water tests to provide the acceleration information necessary for the naval architect to refine the hull lines to the point where the yacht can meet the speed desired and provide a comfortable ride for the passengers. It also provides the information necessary to develop hull structure which will withstand the punishment heavy seas can hand out.

FRYCO has conducted tests at many of the best model basins in North America and Europe Normally we conducted over 100 test runs at various displacements, longitudinal center of gravity, different bottom configurations and several sea states. The results almost always yields some interesting and useful information to increase performance or comfort.

Why do you have a model of the exterior of the yacht?

These works of art are called "styling model" and they are recommended for every new design. Even with computer drawings and color illustrations some clients prefer a three dimensional sculpture so that they can view all angles and be sure that the styling is exactly what they want. Even though a styling model is costly, we feel it is certainly justified. A five to fifteen thousand dollar investment to know what a five to fifty million dollar yacht will look like amounts to pretty cheap insurance.

A styling model is also very helpful to the designer to arrange the necessary antennas, radar and other support equipment in an aesthetically pleasing way.

On large complex jobs it is not uncommon to build interior models of details or even the entire yacht. Although they can cost thousands and take time, it is another worthwhile modeling tool.

Why design the yacht to class?

The world outside of the USA would never ask this question, since elsewhere all yachts over 24m (79 ft.) in length are built to class in most places; however, in the States it has been our practice for many years to depend on the designer and builder (often the same person or firm) to do a good job. With the event of ISO standards and ISM code requirements, plus the gradual tightening of yacht entry requirements by many countries, if you plan to do any international cruising, it is certainly recommended that any yacht more than 24m (79 ft.) long be built to class.

The classification society sets standards for the designer/builder to follow. The requirements are not tough and are well thought out for the safety of the passenger. Some rules regarding hull openings, railings and doors are ignored by many; however, those are the guys that have never been caught out in really bad weather.

Class assures minimum hull strength and subdivision needed for a major investment. The bankers and insurance companies appreciate the fact that an independent expert has reviewed and approved the plans and inspected the construction. The annual survey by the Classification Society is an audit for the owner by an independent agency to assure that the crew is on their toes and that all necessary maintenance is performed to keep the investment in safe operating condition

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3050 Scarlet Oak Pl.

North Fort Myers, FL  

33903-7149, USA 

Ed Fry 


Ed Fry
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