Sixteen guys attended this unique hands-on boat building seminar lead by Derek Kelsall, the yacht designer and boat builder of over 30 years experience. Flying in from as far away as Hawaii, and as close to home as Berkeley, a team group assembled Friday morning to take on the task of learning how this method can allow sailors to realize their dreams of owning a multihull by home building it. The process is straight forward, and perhaps is allure is its simplicity.

The assembled throng this year, consisted of primarily experience boat builders, in contrast to the previous year of largely amateurs. Two flew in from a boat yard in Washington, eager to enter the large power cat multihull market wanting to know more about this unique system.

One of the challenges with the many alternative approaches to boat construction is how to communicate effectively the details of the method, such that inexperienced home-builders can take these on themselves. Here Derek Kelsall has taken the novel approach of leading hands-on workshops to allow attendees to learn through experience with a small project before they take on their personal own dream building. This allows attendees to learn, and make mistakes and understand why and how to ensure a successful project with the home build. Derek offers a range of "off the rack" multihull designs and can provide custom designs to order, all using the simple KSS method.

So what is the method, well more akin to dress making than boat building, it achieves the shape and finish through lamination of foam fiberglass and gel coat on a flat table, then through well placed cuts and grooves bending into shape.

The Table is a high gloss black melamine on a chip board backing of ¾ inches. Lamination of the table can be achieved by the home builder or obtained from a kitchen work top laminator. In this case, the later was procured from Ascend Manufacturing in Gilroy California, in three 8 x 4 sheets. Larger sheets are also available, (up to 12ft by 5ft). This meant that two joins had to be made which was a achieved by screwing 6 x 4 ft melamine sheets under the joins. The joins were then filled with putty to prevent resin from seeping into the table.

While any high gloss surface color can be used, black is selected to make it easier to gauge gel coat thickness. The surface material used is table top variety rather than the thinner vertical mount materials used for cabinet doors. The legs for the table consisted of standard saw horses from Home Depot placed evenly along the table.

The table is then waxed with mold releasing wax, in this case 3 coats were applied to the table to ensure an easy release of the hull panels from the table. (Here we see laying down the resin on top of the gel coat for the first layer of fiberglass)

Derek's boat plans provide table marking details, and the next step is to mark the table with the stations that will eventually form the hull panel. Each hull is formed by building two panels, then literally joining them together.

Once the table has been marked, the area to be gel coated is masked using 3m masking materials. Note only the above the water line of the panels are gelled, primarily the surface that remains flat ie the sides of the boat. The gel is then mixed (more on this later) and rolled onto the flat table service, note no vertical application and streaks to worry about.

The gel is left to cure, then biaxial glass is laid over the gel and then a layer of ½ inch foam is applied, followed by plastic fencing used to provide an airway prior to plastic sheet to form a vacuum bag to ensure a solid bond between the gel, glass and foam and remove unnecessary excess resin from the build. The objective here is to have a lightweight foam sandwich, and the vacuum bagging is a simple elegant way to meet these objectives.

But aren't vacuum machines expensive, can be, but this is an unsophisticated method, and a simple shop vac from Home Depot is used, with holes placed in the sucking tubes to reduce overall vacuum, and to allow airflow to cool the motor. Too little vacuum is not a problem, but too much is, especially if the vacuum fails or there is a power failure allowing air to be sucked back into the fabrication. Household vacuum cleaners are often used for small KSS projects. They have plenty of pressure, but can overheat. We used a Shop vac, and drilled holes into the vacuum pipe to allow for plenty of air to cool the vacuum motor.

Day 2 morning, and the first moment of truth as arrived, the removal of the first panel from the table. The group surrounds the table, as Derek carefully guides the team through the gentle prising of the panel from the table. Remember that the panel has only had 20 hours to cure, so needs to be handled with care during the removal stage. Gently removing the panel from the flat table using plastic scrapers, then placing hands along the outside edge to encourage it to lift. A metal scraper is used to encourage the panel to be removed from the deck edge radius, and cleaver piece of pre-planned molding that goes along way to ensure a nice overall finish and easy junction between the hull and the deck when later attached.

Now that the panel, still face down has been removed, its is gently turned over for all to witness the superb production quality high gloss finish that has been transferred from the high gloss table top to the panel. Wows are heard to ripple along the throng like a Mexican wave as they all appreciate the beauty and success of the teams work. Almost all are drawn to place hands over the shinny surface, and give it a little rub, almost in disbelief. The "professional builders" amongst the team are heard to lament the 1000s of hours that have spent long boarding to achieve this type of finish, a method used to create a surface for custom projects by sanding for hours at a time. Some described this as magic, and the solution to one of the concerns of the home custom builder, how to achieve a production out of the mould quality without the professional skills needed to achieve this through other methods.

At this point, everybody gains an added element of enthusiasm, and the skeptics amongst the crew start to become more involved. Needless to say, the marking, layout for the second panel moves ahead quickly, as the group of unacquainted now becomes an effective team wanting to repeat the experience quickly. The lamination of the second panel takes almost half the time of the first panel, as knowledge turns in to skilled action as folks realize that this is not that difficult.. but the second panel will prove if this is repeatable.

After the vacuum has been applied for the second time, Derek conducts a group talk to explain the process, and how it evolved, and in fact how it continues to evolve through the experience of builders around the world discovering minor enhancements to the process.

Derek explains how a 54ft Catamaran hull has just been built in New Zealand and from panels to hull shape was achieved in less than 2 hours. The bigger the hull, it seems the shaping becomes easier.

One of the keys to the KSS method, is that it is a non stress method. Unlike tortured ply, where plywood is forced around bulkheads to form the desired shape, then held by pinning. Fiber has a short term memory, and if you bend it, will spring back into its original position almost immediately. If held in a bent position, after a few days this will become the new base shape. All the stress dissipating overtime.

Simple frames are constructed; these will be placed along the hull panels and used to pull the keel line down from inside the upturned hull to form the correct shape. A "T" bar has been fabricated that will be placed along the keel line.

The object of the "T" bar is to keep the keel line straight, and to provide a purchase by which the panel finger can be pulled into shape from the frames. The "T" bar is constructed of aluminum angle iron, welded together with ideally welded lugs that provide the connection via rope to the frames.

Now the second panel is removed from the table, same method as the first, and again the Wows surround the table, with the inevitable brushing of the "Oh so smooth" surface. So two production quality finished panels, yes its repeatable, this is way too easy!

The panels are now laid together and cut to size, to ensure that they are an accurate pair. Slots are cut into the foam along the keel line at regular intervals, these will allow the panels along the keel to come together without binding which will become a shorter distance when bent into shape. The panels are then turned over and dart cuts (to use a dressmaking term) are made into the foam/glass. Grooves are cut into the naked foam area where the hull bend is to be encouraged.

(When a piece of foam is bent, the outside tends to stretch a little, and the inside tends to compress. Cutting slots partially through the inside of the curve helps to promote bend more easily and at the desired location to form the correct hull shape)

The panels are now placed together and ties are placed along the circumference of the hull keel to hold the panels together. These ties are also used to hold the "T" piece in place. At this point the upturned panel is placed on supports hanging from the roof that allows the team to be placed at each station to enable the carefully action of pulling the keeling down into shape forming the curve of the hull. The temporary frames are placed at the hull stations before pulling down the "T" bar to the simple frames. This is completed gently and progressively along the stations, and takes about 20 minutes until all stations are firmly in place, with the "T" bar making contact with the frames.

Wows, the second magical part of the process, where flat panels come together to form a perfect hull shape, and with minimal effort. The professionals quickly gather at the end of the hull, to cast experienced eyes along the bottom of the hull check for trueness, and all agree, KSS works!, the best way to build any custom multihull!

KSS is not dependent on using any particular resin. Derek uses polyester or vinylester resin for most projects. He quotes his long experience and the entirely satisfactory results of using polyester for standard cruising craft over more than 35 years of working with foam sandwich. and agues 'why pay more and involve special handling techniques for a more toxic material'.

In this case ortho thalic polyesta resin was used, your basic low cost laminating resin. This requires simple mixing with a gel time in the order of 45 to 60 minutes depending on temperature. Derek instills the value of good record keeping of mixing, temperature, gel times for all fabrications to ensure optimal selection of times, and to provide a track record incase something goes wrong.

One of the key learning exercises of the KSS workshops is that small groups of attendees are selected to go and laminate panels on their own, to demonstrate their understanding of the process. This is achieved without the guidance of Derek or the other attendees. Watching others, or event participating is not the same as getting down and doing it yourself.

A group was selected to laminate a small panel, 24 inches and 24 inches, gel, then glass, then foam then vacuum bag. In this case done as a single process without the delays between the coats. Our team of volunteers first marked out the table, then rolled out the gel coat and waited a while for it to gel. This didn't happen, as the team forgot to add the resin. Gel coat is just another form of resin, with pigment added, and needs the catalyst to set it off. Each member of the team believing that the other had mixed in the catalyst. Understanding their error, they removed the gel coat from the table with acetone, and then proceeded to re-polish the table.

Starting again, completed the process and vacuum bagging. The next morning proceding to remove the panel from the table, discovered that the panel had bonded itself too the table! The panel was removed, but destroyed in the process. The value of the hands on workshop is that attendees get to make their own mistakes, on test pieces as part of the workshop rather than on their own build project.

Boat building is as much about getting it right as it is about fixing mistakes. The team learned how to remove the gel from the table top while protecting the surface from damage to be used again. The lesson learned here was that one needs to ensure that all traces of acetone are removed, and the polish layers have time to dry before being rubbed off to a shiny protective finish.

The afternoon of the third day was spent taking a trip to Napa, no not to drink from the vines, but to view a 54ft Catamaran that had been built via the KSS method. There are several projects taking place around the world using this method of construction, perhaps the most recent is a 54ft catamaran in New Zealand. Taking a mere two hours to shape from flat panels to hull shape.

While the project here was selected to aid the build completion in just over 2 days, this project could have been completed by just two people in about the same time. One of the benefits of this method is minimal waste in materials that optimize it for cost effective construction at home. The build environment was not a sophisticated workshop, but an open car port with plastic sheeting along the sides to minimize the extremes in temperatures experiences recently in Northern California. Simple tools were used, the selection of polyester resin minimizes the problem often faced by users of Epoxy developing allergies to the more toxic resin.

Derek and Paula went on to the second KSS workshop in Mars near Pittsburg, PA. He reports similar enthusiasm and successful outcome in producing an Amkat 30 hull to basic hull shape. Close to 30 have attended the two workshops and 100% expressed satisfaction with both workshops and the KSS method. Judging from the spontaneous reaction at various stages in the process, such as when the first panel is released from the table or when the hull is formed into shape, it would be appropriate to say that the majority found KSS exceeding their expectations.

Would YOU like a multihull, want to learn a simple cost effective way to build one? Check out the following web sites, or contact Derek Kelsall or Ray Walker for details of the next KSS hands on workshop, and come and join the fun!