THE KIT PROCESS

Step 1

The first step to building your dream catamaran begins with a strongback – this is a square frame used to position the temporary frames that will be used to form the hull shape. This frame will be set up and must be square and accurate, a string or laser level can be used to achieve this.

Step 2

Once you have released the pre-cut frame panels, they are erected along the strongback in sequence. The hull panels will be laid over this framework to form our hull shape.

Step 3

Here we can see the hull has now been taped and glassed, ready for turning soon. Once this has been completed the hull will need to be rolled over and the process repeated to produce the second hull. The use of flat panel construction techniques and the time-saving element of pre-cut kits really becomes noticeable. Having this head start is invaluable and could save almost 1000 hours on your build. (Wilderness 1100 design shown.)

Step 4

The fairing is now complete, this is done using a filler compound mixed with our West System epoxy resin and applied to the surface of the hull. This process is to ensure that when painted the boat will have a smooth and glossy appearance, and as a general rule the more painstaking the paint-job and fit-out, the higher your resale value.

Step 5

Now comes the turning of the hull! There are many different ways to do this, some involve cranes or complex equipment, however the smaller designs can simply be turned with a few extra pairs of hands, or a block/pulley set-up. Once both hulls are turned the tops of the bulkheads will be used to join the two hulls, and then the bridgedeck component will be installed underneath.

Step 6

The hull now turned, the second must be positioned and aligned before the large bulkhead panels are used to fix these together. Once this is complete, she will start to look like a catamaran!

Step 7

The forebeam is now installed along with the striker attachment fitting, as shown above. The bridgedeck is installed shortly after and taped onto the bulkheads with webs installed, this now completes what is a quite stiff and strong platform to work on.

Step 8

Now that the bridgedeck is in place, the forward webs and dash will be fitted. At this stage, all furniture and internal work begins, with the main panels left off for ease of access when working.

Step 9

The internal furniture is now installed, if you chose Kit Option 2, this furniture will be pre-cut to your previously decided upon layout. If you chose to receive blank panels, this is the period in which your internal living areas are to be built. This construction uses paper-honeycomb Duflex panels, as these are superior in weight when used non-structurally. Cabin soles, engines and daggerboard cases are also now installed.

Step 10

The transoms and cockpit area are now completed, along with the targa bar, if you’ve chosen this option.

Step 11

The next step is our hull-to-deck joins, side decks and close the shell. As you can see strip planking methods are used here to ensure a pleasing design to the eye. This technique is not difficult and the planks are once again glassed in place to ensure again stiffness and strength.

Step 12

The cabin roof will have been built seperately from the boat, and dropped onto the bulkheads when needed. The cabin sides are then installed and we have a cabin. The next step is to carefully mark our window lines and get cutting.

Step 13

Cutting of hatches, portlights and your saloon windows is now done, edges must be cored. Interior and exterior painting can now be completed after fairing.

Step 14

Fairing is now completed and your final finish needs to be achieved. How extravagant you want to get with paint choices and decals is up to the owner and the project budget.

Step 15

Fairing is finished up and the shell is ready for painting. This is as far as the Schionning kit will get you – from this point on the finishing touches, rig and deck hardware, equipment and appliances must be installed along with finishes such as carpet, roof linings etc. We can supply you with a rough sail away estimate based on other finished projects of a similar size when enquiring about a design, so don’t hesitate to email us if you’d like to investigate further, the build process can take a while to get your head around and we certainly understand that.

Step 16

Once installation of major systems and finish has been completed the boat can be launched. Again this is something that should be planned beforehand however our designs can safely be loaded onto a flatbed semi-trailer sitting solely on their bridgedeck without any problems. So as long as you’re within a reasonable distance, a simple truck hire should be sufficient for your launch.

Step 17

Once the mast is stepped, its time to go sailing!

Step 18

Building your own boat is a rewarding experience and you’ve built a valuable asset on which you can make a considerable profit. If you have any questions regarding build options or designs, please contact us.

MATERIAL CHOICES

 WHAT DO WE USE AND WHY?

Our designs are based on cored composite construction techniques using West System epoxy resin and knitted fabrics. But given the range of today’s composite technologies, which solution works best for catamarans and why?

Resin Choices

We use West System epoxys for their high strength and adhesive values. It also fully protects the boat against water absorption and it can not develop the dreaded Osmosis. We choose ATL Composite’s resin systems for their superior quality, reliability and value for money. Having worked closely with the ATL Composites team and their products for many years, we know we can stand by their material solutions, and rely on great service should something unexpected happen.

Cloths

We prefer Colan brand cloths for their quality and low resin absorption, custom made for Schionning Marine at six (6) stitches per square inch for easy wet-out and rounding corners. This may not seem important but when working with a material for an extended period of time, the small things make all the difference.

 Cores – Which one to use?

The core choice is usually quite confusing. Cores have different capabilities and properties, and their benefits I feel are utilized fully in our catamaran designs. A quick look at their abilities:
Balsa end grain (150 kg/cubic metre) has exceptional qualities including very high compression strength, extremely good sheer capabilities and fantastic sheer stiffness.
Compressive strength is the resistance to collapsing when pressure is applied perpendicular to the surface as when pushing directly onto the material with the point of your finger. Balsa is far stronger than Foam (80kg/cubic metre) in compression. Foam is stronger than honeycomb type cores, both the paper and the plastic.
Balsa is also far better than foam or honeycomb in sheer. This is when the core sample is held flat between your hands, one hand slid one way and the other slid the opposite way, when the core tears through the middle the core has failed in sheer. The amount of stretch you feel before the core shears is shear stiffness. To compensate for sheer weakness the core is made thicker. So 13mm Balsa may be equal in sheer to 19mm Foam.
Paper Honeycomb (50kg/cubic metre) is very efficient and lighter than the other core choices. This can be used for external use but needs extreme care to prevent water penetration. Ideally it is used for all internal furniture and smaller bulkheads. Should water get into the core you lose 50% of its values. It can be suction dried and restored back to full strength, though this can be a long process. Paper Honeycomb has similar strength and sheer ability in the vein lines and about 80% across the veins compared to Foam.
Our hull skin thickness is quite thin, we therefore find the core works harder and it’s stiffness is noticed in the finished structure (sheer stiffness). Generally a balsa or WRC shell is noticeably stiffer than a foam boat using equivalent laminates.

 

COMMON SENSE SUMMARY:

Core Weights: Balsa End Grain 150kg per cubic metre

SuperLight Balsa 94kg per cubic metre

Foam 80kg/cu.m 80kg per cubic metre

Paper Honeycomb 50kg per cubic metre

Western Red Cedar 360-380kg per cubic metre

Balsa has very good values and we can produce a shell using a very light laminate. It will be very stiff and very resilient to fatigue.
Foam – There are many boats sailing that are built from foam so even with it’s poorer values it works well. Initially one would expect this cat shell to be lighter as it is ½ the weight of Balsa. We do have to compensate for its weaknesses and will then add at least double the reinforcement on the outside to spread that compression load over more core and need a triaxial type weave to compensate for the veneer content that runs fore and aft on the Durakore. Secondly, we need to increase the Core thickness to compensate for the shear value, usually neutralizing the weight advantage. Thirdly, foam absorbs a lot more resin into the open surface cells than timber and so increases weight. Fourth, foam is an inert type material tending to follow the surface and not naturally stay fair, fairing usually uses more bog and again adds weight. Fifth, because of the inert characteristics, foam requires a much more complex control mould, this takes a lot more time and is slightly expensive.
The end result using Foam, in my experience, is always a heavier shell with less stiffness. Professional builders can achieve a good result but usually use vacuum bagging and very good molds to achieve this.
The Wilderness 1230 has a foam option. It weighs 200kg less than the Balsa version.
Honeycomb needs to be much thicker and needs much heavier laminates which makes it a silly choice for cat shells. (Nomex excluded)
Western Red Cedar has all the advantages of strip Durakore, but has a real weight penalty because of its higher core weight.
These are the reasons we prefer Durakore and Duflex Panels for our home built designs.

 Secondary Issues

1. Water penetration into the cores
Balsa can absorb water. It needs extreme neglect to rot (very unusual). Water soaks along the end grain quickly. It travels very slowly across the grain. We use balsa under the waterline especially because of it’s high compression strength for beaching etc. any core type must be sealed. Damage to all cores results in the same sort of repair. Notice a damp spot remaining when drying out to anti-foul… simply grind back the surface glass exposing the core, dry it out and re-glass – it’s that easy.
2. Cost
Timber cores are cheaper than Foam in most cases.
3. Resale
A light, high tech cat returns a far better (often 2 – 3 times) re-sale than lower tech. Materials. Often saving 10k on materials initially, loses 200k on re-sale – a serious reality.
Our boats can be built using Balsa, Foam or Western Red Cedar. Combine strength, stiffness, lightness and cost, with ease of use – it just makes good sense!