Creating A New Yacht Design
Copyright 2010 Michael Kasten
Updated May 2010
The Design Process
The following is a summary of how a new custom yacht design is imagined, sketched and drawn. While seemingly complex, the design process is made up of a series of incremental steps, much like the building process itself. If the resulting design is to be what it should be, each of the steps outlined below must be addressed thoroughly.
The goal of undertaking the design of any new yacht is to take a unique set of owner requirements and to turn them into the best possible solution to those requests.
There is first the idea, and then the bringing forth of the idea into a functioning reality. In order to get the relevant information on the table, two primary ingredients are necessary:
I. Owner's Specification: The first 'design task' is actually performed by the prospective boat owner. It is first to imagine the goal, and then to create an 'Owner's Specification' or 'mission statement' for the proposed vessel.
- Rather than being a detailed description of the result of the design process, the Owner's Specification is better if seen as a general guide to the intent of the design.
- Toward that end, ideally the owner's 'mission statement' will be kept fairly simple, since the details of the design will emerge as a result of the design process itself.
- The basic information needed is an outline of the intended vessel's size, layout, materials of construction, the intended use, range, speed, rig, and general aesthetic.
II. Design Proposal: My first job is to understand the preliminary Owner's Specification, then to provide the prospective client with a detailed outline for creating the new design. This is in the form of our standard written 'Design Proposal' which includes the following:
- A written outline of the design process itself.
- A list of the deliverable drawings and documents.
- An estimate for the design work required in order to create the design and to detail the plans for the vessel as described.
The following paragraphs describe our design process as well as the deliverable drawings and documents.
Stage I - The Preliminary Design Study
After our 'Design Proposal' has been reviewed, if our prospective boat owner decides to have a new yacht design created the actual work can begin. There will be a series of information exchanges, possibly including clippings of similar vessels or sketched layouts provided by the client.
Once the client's requirements have been articulated and thoroughly understood, I will prepare preliminary 'Design Sketches' showing the proposed Plan and Profile layout, the Exterior Styling, and the approximate dimensions of the vessel.
These may be as simple as a freehand "napkin" drawings to record the intent of the design, or may be in the form of a few CAD generated possibilities. If preferred, this can become a nicely rendered preliminary Study Drawing. This is the beginning of what I refer to as 'Stage I' or the preliminary 'Design Study.'
A preliminary computer generated 3D model of the intended vessel will be created right at the outset, which allows us to determine:
- The envelope available for the accommodations
- The overall size and hull form
- The preliminary internal structure (bulkheads and soles)
- The rig (if for a sailing vessel or motor sailor)
- The styling and features of the superstructure
- The preliminary hydrostatics
The preliminary 3D model is usually quickly created by adapting one or more of our existing design prototypes to the new purpose. A sampling of these can be accessed via links on our Prototypes web page. Two prototype designs that nicely illustrate the results of Stage I sketches are the 60' Steam Yacht and the 54' power yacht Greatheart.
The goal of Stage I is to establish the accommodations, styling, size, dimensions, and the target displacement in order to provide a "proof of concept" for the design.
When these preliminary sketches have been approved by the owner, Stage II can begin.
Stage II - The Estimating Plans
With owner feedback from the 'Stage I' Preliminary Design Study, we can begin 'Stage II.' The goal of Stage II is to create the first few sheets of full size Building Plans, and to generate a number of essential documents.
The first part of Stage II involves finalizing 'Stage I Study Drawings' to produce the first few sheets of the Estimating Plans drawings, including:
- The proposed Sail Plan or Outboard Profile Drawing
- The proposed Interior Profile and Arrangement Drawing
Once those drawings have been approved, we can proceed knowing that further changes will be minimized. When completed, the Estimating Plans Package will include:
- Sail Plan / Outboard Profile
- Interior Profile and Arrangement
- Structural Profile and Arrangement
- Equipment List
- Vessel Specification
- Painting Specification
- Preliminary Weight Study
- Preliminary Power and Range Analysis
- Preliminary Hydrostatics Analysis
- List of Boat Builders Suited to the Project
- Designer's Cover Letter to Builders
- Sample Owner's 'Request for Quotes' Letter to Builders
For smaller vessels there will be three drawing sheets at this point. For larger vessels there may be two or more sheets in each category.
The goal of Stage II is that enough information be presented in the Estimating Plans Package that firm quotes can be obtained from prospective builders for construction of the vessel.
If you would like to review an example of our design work up to this point, Study Drawings and Estimating Plans are available for the designs listed on our Plans List page.
Stage III - The Building Plans
During 'Stage III' the remaining design work is completed. With additional owner and builder feedback, further decisions can be made with regard to equipment and finish in order to accommodate the overall budget for the project.
The drawings and Vessel Specification are refined to include any requested changes, then the remaining drawings are completed in order to create a final Building Plans package. These several drawings will finally settle the interior and exterior details, the machinery arrangement, the deck plan, the scantlings, the construction sections, and all of the boat's final dimensions.
From that final hull shape, the as-designed displacement, range, performance predictions, hydrostatics and stability can be determined. The Building Plans will include:
- Outboard Profile: Sail plan or other exterior details of the hull
- Interior Profile and Arrangement: The vessel's accommodations
- Sectional Views: Structure and interior joinery sections
- Inboard Profile: Structure and primary equipment
- Deck Plan: Cabins, hatches, fittings, mooring and anchor gear
- Spar and Rigging Plan as needed
- Various Structural Details as needed
- Scantling List
- Hull Fitting Details
- Hatch and Deck Fitting Details
- Companionway, Door and Portlight Details
- Interior Joinery Details
- Mechanical / Machinery Details as needed
- Lines Drawing
- Rudder Details
For larger vessels, each of the above drawing categories may include several sheets.
During Stage III the weight budget is finalized, the final as-designed stability and performance analyses are done, and the Vessel Specification is finalized in order to accurately describe the intent, the layout, the scantlings, the construction, the systems and the outfit of the vessel.
In addition to the drawings, there will be the following documents in a Building Plans set:
- Offsets Table (unless the vessel will be NC cut).
- Equipment List: The complete list of equipment items.
- Vessel Specification: Details of the intent, rationale and construction.
- Painting Specification
- Welding Specification for metal structure
- Fastening Schedule for wooden structure
- Laminate Schedule for GRP structure
- Weight Budget
- Hydrostatics and Stability Report
- Power and Range Analysis
- Letter to Builder
Having finished Stage III, the Design Phase of the new yacht will be complete. Sufficient information will be contained in the drawings and documents to allow any professional or amateur builder to build the vessel as intended.
Then the Construction Phase of the project may begin.
Standards Used
Design Goals: Throughout the design process we have the following goals:
- Suitability to the owner's requirements and to the intended service.
- An interior and on-deck layout per the owner's requirements.
- A pleasing aesthetic.
- A thorough specification to assure longevity and ease of maintenance.
- Sensibility of structure for the sake of ease of construction.
- A functional and accessible machinery and equipment layout.
- A distribution of weights to provide correct trim and adequate stability.
- Performance suited to the expectations of the vessel type.
- Structure per classification society scantling rules.
- Stability per international criteria.
The general attributes of seaworthiness, seakindliness, strength and durability are considered to be requirements for each of our designs. It is interesting to note that for private yachts within the US, there are no requirements for stability or for structure. However we feel it is essential that yachts be held to the following standards as a minimum...
Structure: When creating a new design, classification society rules are our guide for structure. We confirm compliance with one of the ABS Rules or Lloyd's Register or the German Lloyds Rule as is appropriate to the vessel type, size, materials or build venue, as follows:
- ABS Motor Pleasure Yachts (yachts from 79' to 200' scantling length - originally applicable to all yachts up to 200' - all materials)
- ABS Offshore Racing Yachts (sailing yachts up to 100' scantling length - all materials)
- ABS Reinforced Plastic Vessels (fiberglass vessels up to 200' scantling length)
- ABS Aluminum Vessels (alloy vessels from 100' to 500' scantling length)
- ISO-12215 for vessels subject to the EU-RCD standards (yachts up to 78' measurement length - all materials)
- British Lloyd's Register (plank-on-frame wooden yachts up to 98' scantling length - applicable to larger yachts on approval)
- Germanischer Lloyds (plank-on-frame wooden vessels up to 115' scantling length - applicable to larger yachts on approval)
Stability: To assess stability we use a variety of criteria depending on vessel size, use and location, as follows:
- For yachts under 24 meters measurement length (78 feet), stability will be calculated according to the EU-RCD standards appropriate to the vessel type and intended use (ISO-12217).
- For yachts 24 meters measurement length and above, stability will be calculated according to IMO or other standards appropriate to the vessel type, size and use.
- For charter yachts in the US, safety and stability are assessed according to the US Code of Federal Regulations (CFR).
When a vessel is destined for construction and use within the European Union, we can prepare documentation that makes obtaining a CE Mark a relatively easy process for the builder.
Construction Support Services
We ordinarily recommend that plans be submitted to a few selected yards for their construction estimates. We have worked with a variety of builders in a number of places worldwide. We will try to match a project with an appropriate builder, even if that may be outside the US.
During the Construction Phase of the process, there may be various requests for additional services in support of construction. Although we don't get into project management per se, we remain available to act as owner's representative during construction whenever we are asked to do so. In other words, although we do not get involved in managing personnel, scheduling or purchasing, when we are asked to do so we are pleased to remain involved in order to manage the flow of information and specifications for the builder.
Additional Drawings, Documents, Schematics...
Ordinarily, system schematics are developed in-house by the builder (e.g. plumbing) or by system suppliers (e.g. electrical). On occasion the owner or builder may request that we provide basic schematics or additional drawings to illustrate specialized features or other details in support of construction, say in order to communicate owner requests to the builder.
For passenger vessels or other commercial craft there may be the requirement to provide additional drawings and reports for documentation and compliance with the relevant standards.
When a vessel is destined for use within the European Union, we can prepare documentation that makes obtaining a CE Mark relatively easy for the builder.
NC Cutting Files
One of the most valuable Construction Support Services we provide for metal boats is to develop NC Cutting Files in order to automate a portion of the vessel's construction.
What is NC...? It simply means Numerically Controlled...
With this, a numerically driven plasma or water-jet cutter can be used to create frames and plates for a metal vessel. One can also use an NC driven router to cut mould frames for a wood or composite superstructure.
It is even possible to carve an entire male plug or female mold out of foam for use in building a composite superstructure, directly from the computer generated surface model that was created during the design of the boat.
This leverages the work that has already been done in order to create the design and can provide a significant labor savings to the yard. It also dramatically improves accuracy of construction. With NC cutting, the labor saved during fabrication of a metal hull will usually pay for the cost of developing the NC cutting files, plus some.
In other words NC cutting is an opportunity to not only effect a true cost savings by shortening the overall build time, but to also improve the quality of the result.
The Role of the Computer
Designing the Boat: We use Maxsurf, a hull modeling and analysis program developed by Formation Design Systems in Australia.
With Maxsurf, a preliminary hull model is quickly generated and an initial round of hydrostatics, stability, and performance calculations performed to see where the design can be improved.
The computer generated model allows the design to be enhanced quickly at an early stage of design before it has become fixed, or even to be modified without too much fuss later in the process. In fact, without such an easily used computer modeling tool (as compared to manual drafting) those subtle refinements would rarely be undertaken even if given a substantial budget.
Several other benefits are also evident. For example, via the computer generated model it is easy to assure that the surfaces are developable, so building a metal or plywood hull is made simpler.
Building the Boat: A substantial benefit of having generated a model of the hull on the computer is that the vessel's structure can also be computer generated and actually pre-cut via computer guided laser or plasma cutting - or in the case of a GRP vessel, the mould created using a computer guided router.
By this method, having detailed the hull plating and structure, the parts are nested onto available plate sizes. The completed plate nestings are then sent to the metal cutters - usually by email.
This is extremely convenient since the cutter can receive the information immediately in order to start the work. When completed, the cutters have a "boat kit" that can be shipped wherever needed.
The Savings: When building a metal boat in a production environment, assuming one-off construction, industry feedback is generally that NC cutting will save a professional builder some 35% or so of the hull fabrication labor.
The percentage of fabrication labor saved by an amateur owner-builder is dramatically greater. For example, consider that lofting is eliminated, as are templating for frame and plate patterns. For an amateur builder, this also eliminates most of the "what to do and how to do it and why" kind of worries...
Other Benefits: Via NC cutting an extremely accurate fit results. For a metal hull this means there will be far less distortion during the weld-up.
For construction in other materials such as GRP, NC cutting nearly eliminates the labor required for lofting and for mold construction. An entire hull and superstructure mold can be carved by five axis NC router directly from the computer generated model, avoiding nearly all tooling labor.
A builder can also pre-cut glass fiber or carbon fiber cloth, especially useful with 'pre-preg' cloth (cloth that is pre-impregnated with resin and post-cured by UV or by heat). Where the materials cost is high, the improved efficiency will quickly offset the cost of having developed the structure via computer modeling.
Yet another use of this technology is for prototyping. With the computer generated model of the hull and superstructure already having been created, it is a simple matter to make a scaled down model for towing tank testing, or to verify the styling of the yacht in three dimensions.
For more detail on our design and build strategy please see our Design Stream article.
Why Develop A New Design...?
As you may have surmised from the above, there is a fair bit of work involved in designing a boat well, even if it is a simple one!
Given the number of designs that already exist it may seem a little bit wild to commission a new yacht design. On the other hand, it is an unquestionable delight to see one's ideas turned into one's own personal yacht.
You will be surprised to discover that the cost to develop a new and unique yacht design is less than a yacht broker's typical fee simply to purchase an existing yacht...!
I'll repeat that in case you missed it... Even though there is quite a lot more work involved to create a boat design, the cost to create a new custom yacht design is less than a yacht broker's fee for the simple act of signing purchase papers...!
As a percentage of the yacht's cost the amount expended on design is really quite small. If you also consider that a custom design will be tailored to ones particular requirements rather than being an "off-the-shelf" solution, the difference in satisfaction is ordinarily well worth the small difference in cost.
This is especially so if a custom designed yacht will better serve its intended purpose and do so for a longer time than a vessel built to a stock design. In other words, by not having to replace the yacht quite so soon the cost of custom design work will have paid for itself many times over.
Is It Proven?
The question inevitably comes up: " Is it a proven design?"
The answer is an unqualified "Yes!"
The basic principles of boat design, while seemingly complex, are well established. If faithfully attended to, the success of a new vessel is assured, and the result will nearly always be an improvement on what has been done before on existing designs.
Where unusual features or hull types are requested, it is prudent to involve tank testing, which can provide valuable insight as to vessel behavior; performance; stability; seakeeping; etc.
What ultimately makes a boat a success is whether the vessel is safe, seaworthy, sea kindly, beautiful to behold, and above all, whether the vessel satisfies the originally stated wishes of the owner.
Our Approach to Boat Design
We design ocean capable yachts both power and sail in all materials. Our aim is to engender superior aesthetics along with safe and comfortable boating. We provide an appropriate form and function and a thorough analysis of performance and structure.
Most importantly, we strive for long term owner satisfaction with the resulting vessel. We use the most up to date methods, including software optimized for hull modeling, stability and performance analyses. We can leverage that work into also detailing the vessel's structure with an NC cutting file package to help automate construction.
Our goal is to provide a complete "design service" from the point of imagining the vessel, to creating the ideal solution to those conjurings. Our specific task is to take the concept all the way from 'napkin sketch' to building plans, and to also provide the various "construction support services" noted above.
Where To Begin?
The place to start the design process is to first create an owner's specification, or "mission statement." This can be as simple as a paragraph to describe the intended vessel, or possibly a simple list of desired features such as preferences for rig, power, equipment, materials of construction, overall size, accommodations, budget, project timing, and so forth.
The owner's 'mission statement' need not be elaborate, since the particulars will be generated by the design process itself... While sketches or design examples are not necessary, if preliminary sketches or examples are available, certainly they can be included.
We refer to the owner's mission statement as the "Owner Specification." Once I've understood its requirements I will provide our usual written 'Design Proposal' - usually by return email or if necessary by letter or fax. Our Design Proposal is offered free of charge and implies no obligation. It is just good information for your planning purposes...
In order to pursue a design inquiry in greater detail, please feel free to contact me for more information or to request a Design Proposal.
Creating a new yacht design is by far the most rewarding path to long term boat ownership, and the process itself can be quite a lot of fun...!
What do our clients think...? Please review some of their Testimonials to find out...
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Please see the Plans List page to review our available Boat Plans.
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