Do-It-Yourself Yachtbuilding
Learning the hard way.

A compelling rationale for designing your own yacht is getting EXACTLY what you desire.  For example: production boatbuilders offer neither "lab-workshop room" nor "espresso bar" options, in any vessel suitable for my single-handed operation.  (Go figure?) I reverse-engineered aspects of my home (like the kitchen's espresso bar at right) and its furnishings which "fit perfect" then developed a minimum envelope definition for such essential living spaces as the bed, toilet, bathroom counter, shower, kitchen, workshop etc.  Combining these with the necessary marine-specific spaces like a helm, foredeck, aft-deck, rope lockers, machinery space and tankage, resulted in a minimum volume requirement for a suitable vessel.  Integrating all these aspects into a workable design mandated an extensive ergonomics study, but the results more than justified the effort.  Deciding on the catamaran platform was a no-brainer.  Locating a custom builder was more difficult, so I joined ABYC and began attending industry trade shows while researching components, materials, fabrication technologies and designs.  While attending the International Boatbuilder's Exposition and Conference (IBEX) during February 2003, I took a day-trip from Fort Lauderdale up to Merritt Island, and interviewed one potential custom boatbuilder.  Their hulls seemed suitable for the SEDATION 4 project.  It looked like I was ready to start building; time to put the house on-the-market.
So ... you want to design and build your own dream yacht?  Experienced folks will warn you that it could cost twice as much and take twice longer than projected.  Bah!!!  I was convinced that the project would be completed on-time and under-budget.  After all, I have decades of production-engineering experience and knew EXACTLY what I wanted from the start.  Over 1600 hours of my design time were invested before I even arrived in Florida to oversee her construction.  NEVER start a boat without a comprehensive design!  The plan-as-you-go approach is proven inefficient.  If you're not a design engineer - hire one or buy some plans.
The boatbuilder purchased a new ShopBot CNC router, using my $20,000 deposit, for this project. I would personally cut every component, using files from my 3D solid model, to assure a perfect fit.  Nothing could possibly go wrong ... right??  Of course, the hull molds already existed (that's why I chose these guys) and dimensions were provided which enabled me to construct a very precise 3D solid model of these fundamental building blocks.  Months later, when we began fitting the first CNC-cut bulkheads into the port hull, there were several discrepancies as expected.  I cut prototype panels from 3/4" R-Max foam insulation panels and tweaked the 3D model based on measured discrepancies.  So far - so good.  The starboard hull should be a piece-of-cake, right??
In this custom boatbuilder's world, symmetry is a relative concept.  Plus-or-minus an inch or two, here and there, is considered "close enough" since their panels are hand-fitted and gaps are just filled-in as needed.  So much for my precise engineering effort!  The 15" vertical extensions of the hulls had to be custom tweaked because the molded hulls' sheer lines are wavy, as evidenced in the picture at right.  This waviness is also quite different side-to-side.
It's a good thing that I insisted on designing and constructing my own roof mold.  Every intersection between my 3 molded roofs and adjacent CNC-cut panels fits perfectly.  The same can NOT be said for panels which intersect the builder's molded hulls.  If you're determined to design/build your own yacht, insist on 100% CAD designed and CNC-cut  molds and components.  The alternative is very expensive, time-consuming, heavy and neither elegant nor pretty.
Unless you've recently won a big lottery, forget about hiring outside help for proper electrical systems installation.  Few do-it-yourselfers can afford true "marine quality" electrical workmanship, and even fewer technicians outside of NASA are willing to perform such meticulous installations, so be prepared to do-it-yourself.  FIRST: buy a copy of Nigel Calder's book "Boatowner's Mechanical and Electrical Manual" and read it cover-to-cover at least twice before even attempting to design the electrical system.  Undersized wires, improper terminations and crappy workmanship are the primary causes of most on-board electrical problems.  "Marine quality" wire and hardware are expensive but careful planning can substantially reduce the requisite costs and complexity.  Your yacht's electrical system is just that ... a system.  Permitting a variety of dealers and "product specialists" to install various sub-systems invites problems.  The resulting hodge-podge will hinder troubleshooting and could even be dangerous.  Electrolysis, electrocution, fire or worse are common results from improper electrical system installations.  There's a reason that successful boatbuilders employ staffs of electrical engineers.  Get it??  If not ... go buy a production boat and forget about building a custom yacht.
Plumbing is another potential nightmare but much simpler to tackle.  Planning Water Use is imperative and a prerequisite to determining the electrical system loads.  Marine grade hose is expensive but mandatory for certain applications, like fuel and waste systems.  Sticking with ABYC, UL and Coast Guard certified hoses, components and fittings will help significantly.  DO NOT SKIMP ON HOSE CLAMPS!!  Quality, 100% Stainless clamps are expensive but the potential for disaster (leaking fuel, sinking) mandates their usage.  Follow the USCG Regulations and ABYC Standards verbatim to assure trouble-free installations. Most plumbing for water, both fresh- and sea-water, can be implemented using readily available PVC tubing and fittings.  I used 3/4" Schedule 40 PVC throughout SEDATION 4 to minimize my on-board inventory of spares and service parts.  This extra-large size also eliminated flow losses, resulting in a quiet, "scald-resistant" system.  Use filters and strainers extensively ... they are much less costly than replacement pumps and solenoid valves.  I also recommend seachests instead of numerous thru-hull fitting to reduce holes below the waterline.
A unique aspect of SEDATION 4 plumbing/electrical systems' design is the LACK of bonding (grounding) throughout the vessel.  There are NO metal fittings or components in the plumbing and no metallic thru-hull fittings contributing to galvanic electrolysis.  The limited 110 VAC systems employ a "floating ground" configuration (like those found in hospitals and labs) since there is no shorepower connection or generator.  The risk of shock is totally eliminated.  USCG and ABYC standards, again, are the best guidelines available.
The experienced folks were right ... it did take twice as long and will end-up costing about twice more than initially projected.  WOULD I DO IT AGAIN??  You bet, but a little differently.  First, I would find some symmetrical 39' hulls (my original concept) instead of the 37' "Kit-Cat" hulls.  Then I would personally oversee every aspect of mold construction/modifications to assure better finish and more accurate geometry.  A few little design tweaks (like 1" more headroom belowdecks and 2" lower ceilings over the beds) and minor revisions to the deck/steps layout would make things truly elegant.  I would employ carbon-fiber laminations in two highly-stressed components to reduce weight and increase rigidity.  Most importantly, I would implement a strict Quality Control program to improve the strength and finish of all bonds and laminations. Peel-Ply EVERY lamination, tab and bond!  This will actually reduce  costs. A significant portion of this project's time and expense is attributable to secondary operations (labor) that would not be necessary if better control of lamination processes was achieved.  Alas, one should always learn from experiences.