The importance of drawings in a (boat) building project
By Tariq Fensham – Owner and MD of Jo Fensham and Professional Architect
A client once asked, “It’s just a cushion, why do you need a drawing?”
We need a drawing because we need to know what our clients want us to build for them. It is a visual, tangible format to express and clarify what our clients want, and it illustrates the idea that all parties can agree on. Drawings are a shared communication tool between client, designer, builder, subcontractor
Whether it is a boat or a building, drawings allow the builders and subcontractors to see what is in the client’s and the designer’s mind, so that all know and can agree on what the end product will look like.
I will give a brief outline of the different types of drawings but will focus on working drawings and why they are important in the boatbuilding industry.
Why do we need drawings?
A drawing is a set of instructions. It is the “hymn-sheet” that all involved in any building or boat-building project can “sing to”, ensuring that everyone works in harmony towards the same result and that the project is completed as intended, on time and within budget.
Drawings ensure that everyone knows what they need to do, how and when, that there are no surprises when the project is completed and that the builders and subcontractors deliver to the clients and their designers what they wanted and were expecting.
I have been in the (possibly) unique position of having experienced drawings from all three of the main positions that drawings are needed. I have been the architect, I have been the builder, and I am currently the sub-contractor.
As the architect, I have produced the design and working drawings that are issued to builders and subcontractors.
As the builder, working in the CAD (Computer Aided Design) office for a large construction company refurbishing the British Airways lounges at Heathrow, I received the architect’s design drawings and, from these, produced working and construction drawings for the builders on site.
As the subcontractor, I now receive (or not!) drawings from the designers of yachts to construct the upholstery.
A good set of working drawings means the difference between a smooth construction project and one that is beset with problems, delays, remakes, frustration and cost overruns.
What are the different types of drawings?
Concept drawings
These are the initial ideas, often sketched by hand, the archetypal “paper napkin” or “back of a fag packet” drawing. They are not detailed, not to scale and not for construction.
Design drawings
These are the drawings that develop the ideas and concept into a presentable design, drawn to scale with more detail than concept drawings. They can be line drawings, including plans, sections and elevations with some dimensions and some notes on materials and other general specifications. These drawings are still not build-ready.
They may also be worked up into fully rendered 3-d presentations that bring the designers’ ideas to life for the client and the public.
Working drawings
These take the design further to the stage where it can be costed and scheduled, providing the designers, engineers, builders and subcontractors with detailed specifications, dimensions and materials required to bring the design to life.
Working drawings are usually accompanied by written specifications, which describe materials, standards, and workmanship requirements in detail, especially important in boatbuilding.
They will also include tolerances, which define acceptable limits of variation during construction.
Detail drawings
Detail drawings take the working drawings a step further and are enlarged portions of working drawings. They focus on a particular aspect of the project in detail and are usually drawn at a larger scale than the working drawings, usually at 1:10, 1:5 and sometimes as large as 1:2 or 1:1.
Construction drawings
These drawings focus on the actual building process and may even be drawn by the subcontractors themselves, for approval by the designer. They will include the specifics of the particular trade, such as engineering calculations or types of steel sections to be used in a staircase, or total air changes per hour in an air-conditioning system.
What is a working drawing and why is it important?
A working drawing is a clear and legible set of instructions from the designer to the builder on how to build or make the intended design.
There will be a set of working drawings for each trade and/or subcontractor to work to.
Issued to all the relevant disciplines in the project team, a working drawing details everything that should go into the project or into a specific aspect of it. Drawn to a specific scale, it shows the layout of the design elements, and will include dimensions, notes on materials and specifications for builders, engineers and subcontractors to follow. A working drawing ensures that all members of a project team know what everyone else is doing and when, so that the various elements of a project are co-ordinated in time and space and that the many disciplines, trades and skills involved in any project can work together to realise the design successfully.
Working drawings provide detailed information that is essential in cost estimation and scheduling. Knowing the size and scope of a project before it starts allows builders and subcontractors to prepare cost estimates and project schedules accurately.
Examples of working drawings include plans, sections and elevations, structural drawings, electrical layouts, HVAC (heating, ventilation, air conditioning) layouts, plumbing layouts and other detailed drawings such as stairs, windows and doors, flooring and ceiling layouts, lighting layouts and more.
These drawings are living documents that evolve as conditions within the project change, serving as a detailed record of the project through time. They also serve as a record of the completed project, so an understanding of the building or the boat can be retained for future use, whether for repairs or alterations, or, as we experience in the boatbuilding industry, for repeated builds of the same design.
In our work, 2-dimensional working drawings are sometimes replaced with the 3-dimensional CAD files which we receive directly from the designers in some of our clients’ design offices. These files are used by the boatbuilders to CNC cut the joinery that our upholstery is associated with and the high level of accuracy of this system means that we can base our own construction drawings on these files with an equally high level of accuracy.
Any project manager, on a building site or in a boatyard, needs to know what the contractor (or the boatyard factory floor) and subcontractors will be doing so that their work can be properly co-ordinated.
What should be included in a working drawing?
Usually drawn in two dimensions, a working drawing is presented in black and white, using different line thicknesses to denote position in space, with thicker lines indicating elements in the foreground or in section and progressively thinner lines representing elements further and further back in elevation.
It will contain detailed notes with clear arrows pointing to the elements referred to, giving specific instructions on materials, suppliers where necessary, such as for stainless steel, or fabric in the case of upholstery, as well as sequencing of construction where required.
These drawings will include detailed dimensions, showing a clear setting out point, and which relate to and follow on from, each other so that builders and subcontractors know exactly how to construct and position the various elements referred to in the drawing.
Good working drawings are clearly titled and numbered, with a clear system for recording revisions using numbers and notes. They are formally issued by the designer (or the builder) to the builder (or to the subcontractor) accompanied by clear issue schedules that record the date, the drawing title, the drawing number, the revision number, the purpose of the issue and the intended recipients, ensuring everyone in the team is working to the latest information.
In the case of boatbuilding, where a boat design is repeated, keeping records of changes is absolutely essential. Design and construction improvements are frequently made during the build process and should always be formally recorded in revised drawings issued to the builders and subcontractors. Undocumented on-site changes made by individual carpenters, electricians or other members of the boatbuilding team can cause delays and increased costs for both boatyards and subcontractors who, when unaware of changes made to the boat, may produce and supply components that no longer fit and must then be remade or altered.
For continuity of the design and for efficiency of construction timing and use of materials, working drawings, and therefore detailed records, are paramount.
A good set of working drawings ensures that no-one is left guessing on the boat, that no-one is unsure about what they are building or making or where or how it should be positioned, and that the client and the designers can be confident that the finished product is, in fact, what they envisaged and wanted.
Drawings ensure that responsibility is clearly defined and that builders, subcontractors, clients and designers know what they are supposed to do and what they are responsible for.
Without drawings, construction becomes guesswork. With them, it becomes a controlled, repeatable, and professional process.
So, when someone asks me “Why do you need a drawing” I answer, “How else will I know what you want me to make for you? How else will you know what you are going to get from me? And how else will you know that I will make the same thing for the next boat?”