Quality and strength above all

Each Dean Catamaran launched typically sails on average 7000nm on her own bottom and usually by the owner to its destination. It is for this very reason that special emphasis is paid to certain items and to our very strict quality control procedure to ensure that no problems occur on the maiden voyage.

South Africa has a very harsh coastline with strong wind and big seas and this is why Cape Town is referred to as the “Cape of storms”. For this reason new technology is mixed with old thinking and tradition, as there can be no compromise on safety and strength.

Below we have highlighted some of the important criteria and in some instances explain why we adopt this approach:

Hull and appendages:

Each vessel constructed is hand laid. This is the tried and tested method.

Although infusion is the new word that everyone is using at the moment, the infusion process has certain problems and we feel it is too soon for production boat builders to adopt this approach. Infusion does not result in a boat that is either stronger or will last longer. Very strict control is kept on our resin ratios, catalyst levels and our entire factory is monitored twice a day recording temperature and humidity. Laminating of the boat hull and deck are only done when the weather is within limits set by the resin manufacturer. We use a special catalyst called Butanox VR. This catalyst has a special red dye inserted into it which makes the gel coat and resin appear red in color. The reason for using this is to ensure that all mixes are stirred correctly. The red color disappears when the product is fully cured. A separate sample of the vessel is laminated at the same time. This is then kept as part of the records. Barcol hardness levels are measured to check that every vessel produced has cured properly.

As a rule all hulls manufactured are solid GRP laminate below waterline. We use a combination of chopped strand mat, E-glass and Quadriaxial stitched fabrics. These fabrics offer 25% more strength and 35% better impact resistance. Above the waterline and on the deck we use a sandwich composite construction technique. The basic principle of sandwich construction is to separate two load bearing skins with a light weight core material. As a sandwich panel will flex slightly under load it follows that one skin will be under compression and the other in tension, therefore the further apart they are the stiffer the panel will be, similar to the I-beam principle in steel structures.

The advantages of sandwich laminates are stiffness, light weight, positive buoyancy, sound and thermal insulation, and helping to avoid condensation in cold climates.

Because the core lies between one skin in tension and the other in compression, the core is subjected to shearing forces, therefore it’s most important property is its shear strength, stiffness, adhesive quality and its ability to withstand compressive loading.

We believe of all the cores on the market today end grain Balsa is superior when compared to PVC foams due to (as mentioned above) the shear and stiffness of the composite panel. It is for this reason we use end grain Balsa as the core. In the deck PVC foams can become soft underfoot when exposed to the sun for long periods of time.

Where apertures for deck hatches, port lights are cut out the Balsa is first primed and then sealed so as to ensure that no moisture can penetrate the core.

All Gel coats and resins used are of the latest technology and sourced from Scott Bader who are one of the largest resin companies in the world. Scott Baders’ primary market is the marine industry, where they dedicate significant effort towards Research and Development. They have recently launched their new Crystic Envirotec range of gelcoats, which offers the benefits of superior Gloss Retention and Colour Fastness over an extended period versus all their international competitors. Dean Catamarans has recently switched over to these new Gelcoats and can see the visible difference between the new and the old. We have a very close working relationship with Scott Bader and they visit our production facility on regular intervals to ensure that we keep up to date with new technology developments, and correct material handling.

All structural bulkheads are approved marine plywood bonded together with Phenol waterproof glue. This produces a very strong, rigid yet light weight bulkhead.

All non-structural bulkheads, flooring, bulkheads and certain furniture are constructed using polypropylene as the core. Nida core is a new polypropylene structural honeycomb material with a density of 80. This product offers sound dampening, light weight, rot proof, impact resistance, and thermal insulation.

Bonding of the hull, deck and structural bulkheads. Here we turn to tried and tested traditional methods as opposed to the new methods. Each bulkhead is laminated to the hull and deck using Bi-Axial stitched fabrics. This ensures a perfect and very strong bond when compared to the new Polyurethanes etc. Most of the big production boat yards glue and stick their vessels together. This might be fine in good weather but we would not adopt this practice on a boat sailing in the southern ocean and sailing 7000nm on its maiden voyage.

The rigging chain plates are fixed to 36mm solid Phenol bonded Marine plywood structural bulkheads in the hull and not simply bolted to the hull as found on other vessels. We do this as the forces from the chain plate are spread over a much bigger area and the hull in one confined area does not take all the loading.

The hull under waterline is primed with two layers of epoxy before antifouling is applied. We apply two different colors to ensure that every part of the gel coat is covered. This epoxy helps protect the gel coat and the laminate from possible Osmosis.

Deck:

A composite laminate of Quadriaxial stitched fabric and end grain Balsa (an end grain, micro-honeycomb structure offering exceptional shear and compressive strength. In addition Balsa offers good fatigue properties, high thermal and sound insulation) is used exclusively as the core. The reason Balsa is used is due to it having a high density value of 155KG/M2. This ensures that the deck feels solid underfoot and will not become spongy when hot.

In areas where deck equipment is to be added marine plywood is inserted in place of the balsa thereby ensuring that deck equipment stays fixed. 316L stainless steel backing plates are used under all deck equipment and fittings.

Each nut whether on a chain plate or winch is tightened to a torque of 70 Newton’s. This ensures that every nut and bolt on the entire vessel is tightened to an exact amount and therefore ensures a good loading spread.

All equipment fitted is sourced from the very best of manufacturers and only well known brands are fitted. Before we use a certain supplier, we first ascertain that they are well represented in all different locations of the world and that they have the proper back-up and after sales service. We do not fit any products that do not meet this requirement.

Stainless steel or Chromium-Nickel-Molybdenum:

Dean Catamarans only uses Allegheny Ludlum type 316L (S31603) stainless steel. 316L are molybdenum-bearing austenitic stainless steels which are more resistant to general corrosion and pitting/crevice corrosion than the conventional chromium-nickel austenitic stainless steels such as Type 304. 316L has a much lower Carbon content and therefore is immune from sensitization (grain boundary carbide precipitation). As an international standard all 316 stainless steel is stamped A4, and 304 stainless steel A2. This is always visible on bolts, washers and nuts.

Cabin windows:

Dean Catamarans only uses Acridite for the cabin windows. Acridite was chosen as Acridite sheets contain a UV absorbent additive which helps to safeguard coloring. Only 20% of UV rays can pass through Acridite therefore ensuring that furniture and instruments are not subjected to harmful rays which cause damage. Sikaflex type 295UV is used to bond the windows to the deck and a film thickness of 10mm is allowed so that the window can float and move during the expanding process which happens twice a day. We say twice a day as the Acridite expands at midday due to the suns heat and later contracts when the sun goes down.

Interior finishes:

All veneers are hand chosen and stitched together. Veneer thickness is 0,7mm. If thinner veneers are used the glue used to bond it to the substrate can be seen after a couple of years. This is particularly noticeable on the lighter veneers such as Maple and Beech.

After the veneers have been pressed on to the substrate they are coated with a sealer and then 5 coats of Polyurethane acrylic lacquer are applied. The wood is then polished.

Only first class or first grade materials are used whether it be the veneers or glues that are used.

Worktop surfaces in the Galley and bathrooms are made from Corian. We specify Corian as it is non-porous, cannot stain and are not prone to mildew or bacteria. Corian also resists burns and scratches. Sinks and backsplashes are perfectly welded to create an illusion of a single solid surface. Corian is also backed by DuPont who have many service centers around the world.

Electrical systems:

At Dean Catamarans all vessels are wired to meet and exceed the ABYC, CE and NMMA standards. All wire and cable regardless of the voltage applied is U.L. listed to provide greater insulation protection. All wire is tin coated (same wire that is used in Aircraft) to prevent corrosion and made from stranded copper for improved flexibility. All wires run in conduits and there are separate conduits for high and low voltage wires. Wires are sized accordingly to prevent any volt drop.

We do not use pre-made wiring harnesses. Each wire is individually run through the conduits. Each individual cable or wire is also marked or numbered. We even mark and number the black negative wires so that they can be traced or replaced in the event of a problem. Every wire and cable is documented in the owner’s manual.

All light current circuits are protected by Carling DC breakers. These breakers are medium break and are not influenced by ambient temperature changes. Only copper tinned heavy duty bus bars are used.

Batteries:

Deltec Freedom batteries are fitted as standard as they allow both engine cranking and deep cycling (approx 50%) in one power source. These batteries are of flooded cell construction with a sealed cover to prevent contamination. They are equipped with a safety vent which includes a flame arrestor and do not require any maintenance or topping up. Deltec batteries feature “Wrought lead calcium” technology which improves the self discharge characteristics. There is a built in Hydrometer in each battery which allows an easy check on charge status. These batteries are capable of meeting engine cranking as well as domestic loads and are resistant to overcharging, heat and vibration.

All batteries have a temperature sensor fitted to them which transfers important information to the battery management controller. This unit regulates the alternators on the engine thereby giving the correct amount of charge at all times.

Water system:

Dean Catamarans incorporates a cross-link polyethylene (BPEX) pipe which is excellent for use on hot and cold fresh water plumbing on marine vessels. The polyethylene provides superior resistance to corrosion when compared to copper or polybutelene. All hot water pipes are inserted into a neoprene sponge covering thereby keeping the water hot for longer. All piping is clearly marked with red and blue indicators easily showing which are cold and which are hot water carrying pipes. Speed fit plumbing connectors are also used giving the owner years of maintenance free plumbing.
Water storage tanks are manufactured from a tasteless and odourless synthetic material. These tanks are easily removable for maintenance and the liquid can be seen from the outside. All tanks have built in molded baffles.

Engines:

Standard fit on the Dean 441 are 2 x Mitsubishi based marine diesel engine. These engines have a two year standard warranty. The Mitsubishi is a 4 cylinder 1758 cc unit delivering 30,9KW or 42HP at the flywheel at 3000RPM. We have chosen this engine as it is stronger, lighter and more powerful than the competitors. It also uses less fuel and runs quieter.

Cooling water strainers are provided with a transparent cover allowing easy inspection of the filter without having to dismantle it. As it has a large surface the filter seldom needs to be cleaned. A water separator and primary fuel filter is also fitted to the engines fuel supply.

Dean Catamarans incorporate a “wet” exhaust system to the engine. A waterlock is fitted which collects the cooling water present in the system when the engine is stopped. In addition to this it also acts as a muffler as it has good sound-deadening properties. A Gooseneck is also fitted which raises the exhaust hose above the waterline so that water cannot backfill the exhaust system.

Spiral reinforced Rubber exhaust hose is used. This hose is Lloyds approved and fulfills the SAE J2006R2 directive. The hose is smooth on the inside thereby reducing unnecessary back pressure. Fuel supply hoses are made from NBR and CR rubber with an inlay of woven synthetic fabric. These hoses fulfill the requirements for Marine fuel A1 and are ISO 7840 approved.

Sails:

Quantum sails are our preferred sail maker as they are one of the largest sail makers in the world with lofts in just about every country. Quantum sails only use sail cloth and fabrics supplied by Bainbridge International. We specify laminated sails as opposed to Dacron as laminated sails using CL-P (Cruiselam) are stronger, lighter and stretch less.

The reason for this is that Cruiselam is a laminated fabric consisting of Dacron taffeta on the outsides, sandwiching one layer of Mylar film and one layer of “Polyester scrim”. The polyester scrim is aligned with the thicker strands along the primary loading areas and the thinner ones along the secondary areas.

These sails, both mainsail, (due to the exceptionally large roach), and the furling Genoa, (due to excessive uneven loadings when partially furled in strong winds), are prone to exceptionally heavy unidirectional loadings and consequently require a suitable fabric to retain shape and give good durability. Cruiselam has proven to be the most suitable fabric for this job.

Mast:

Sparcraft South Africa are the chosen mast manufacturer for Dean Catamarans as they do not have the philosophy of “one mast fits all”. The mast on the 441 has been specifically designed to be strong, long lasting, trouble free and to withstand extreme conditions for prolonged periods of time.

The NG86 mast section has been specifically chosen for the Dean 441. Some of Sparcrafts competitors use bigger mast sections, but with thinner wall sections to thereby reduce alloy costs. This also increases windage.

The heel design of the foot of the mast is more robust and allows for various rake angles and to efficiently transfer the load of the rig through the right camber. The heel is a highly critical area of the rig so therefore is machined from solid aluminium rather than using cast heels made in China.

The fabricated Gooseneck and Vang attachments allow for full marine grade anodizing to reduce corrosion. These attachments are custom designed specifically for the Dean 441 after taking into consideration the huge mechanical loads applied. All pins used in the attachments are bushed to allow for proper servicing to adequately deal with the rigors of a sailing catamaran of this size.

The spreader bases have wider support bases to minimize local compression on the mast section, have also been custom designed and fabricated. The spreader attachments are a highly stressed area so special care was taken in the design process. The wider bases also eliminate sloppy spreaders, therefore lengthening the life of the mast and attachments.

The specially fabricated mast head was designed specifically for the Dean 441, as opposed to the generic drop in heads which are not as strong and robust. The generic heads are also prone to halyard chafe.

Dean Catamaran’s masts are raked aft by 7 degrees. This unusual feature assists both the yachts upwind performance, and its ability to tack through the wind without the difficulties associated with some of the other catamarans on the market today.upwind performance, and its ability to tackthrough the wind without the difficulties associated with some other catamara

Steering position:

The first of the Dean 400 series was launched in 1990 and this catamaran had twin steering wheels mounted in the aft section of the cockpit. Although good for racing we soon realized that this was not good for cruising boats. There can be nothing worse than standing in the sea spray, wind, rain and sun.

Some manufacturers have even gone so far as putting the cockpit on top of the coach roof. This might be fine for day sailing but we cannot see the owner sitting up there with his wife crossing the Atlantic.

The traditional place for a helm has always been on the bulkhead and we accordingly put it there as it offers the most protection from the elements. The helmsman is also in total control of the vessel as he is near the navigation table and can socialize with the guests on board.

Warranty/communication:

Dean Catamarans is owned and managed by two directors who are directly involved in production and design. Therefore when there is a query or a question, quick and professional advice is given. We even go as far as to have the office and mobile contact numbers printed on the builder’s plate which is affixed to each vessel next to the navigation table.

What this means is that we can be contacted at any time. We also have a professional dealer network covering most countries so if a problem is encountered for what ever reason the respective agent will be able to be contacted.

Quality Control:

We adopt a very strict and professional approach to quality control procedures and have them in place. Quality control at Dean Catamarans is not simply a checklist which someone fills in because they are paid to do so.

At Dean Catamarans quality control begins with procurement and ends when the vessel is ready to be handed over to the client.

Every item ordered is checked and signed for when delivered. All equipment is marked with the vessels number and put into allocated store rooms. Once fitted it is documented and checked by a supervisor.

5 days before the vessel is ready to be launched, the vessel is inspected by means of a formal inspection. A 76 page document is used as a format to check and every single piece of equipment that was fitted is once again checked. Only when this document has been signed off can the vessel be launched.

After launching the vessel is commissioned and once again another checklist is used to check certain items that have to be adjusted and calibrated. Only once this document has been signed off can the vessel be handed over to the owner. This handover usually takes a full day and all aspects including electrics to plumbing are explained.

We are passionate about our yachts