Quality, strength and innovation – The new Dean 498

Each Dean Catamaran launched so far typically sailed 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 or at least very few minor 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, especially now on our new model – THE DEAN 498

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 and PVC honeycomb are 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 and honeycombs 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 constructed using 936 G/M2 Bi-Axial stitched glass cloth with 25mm PVC honeycomb as the core. This produces a very strong, rigid yet light weight bulkhead.

All non-structural bulkheads, flooring, bulkheads and certain furniture are constructed from PVC honeycomb. 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 bolted to the hull however very close to structural bulkheads. We do this as the forces from the chain plate are spread over a much bigger are.

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 certain areas of less stress PVC honeycomb is used.

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 and hull 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 6 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 498 is the Vetus -Mitsubishi M4-55 turbo charged marine diesel engine. These engines have a 5 year standard warranty and are serviced by Vetus who have outlets worldwide. The Mitsubishi is a 4 cylinder 1758 cc unit delivering 38.3 KW or 55HP 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. We even go as far as to fit a secondary emergency fuel shut off valve just before this filter so that changing filters is easy.

Almost all large production catamaran manufacturers install sail-drive propulsion units because they are quick and easy to install. We do not fit them due to electrolytic corrosion problems and since 2002 have been fitting conventional prop shafts and propellers. The “bullflex” flexible coupling is specially designed to ensure optimum damping of vibrations. Torsional vibrations which are due to cycle irregularities (especially at low revs) are smoothed out owing to its very flexible rubber element. This pre tensioned rubber element ensures low-noise and vibration free transmission without backlash between the engine and the propeller shaft. On the 498 we have opted for the V-drive shaft system.

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 and as a further prevention fit an anti-siphon to the engine as well

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. They are also fire resistant

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 Jib, (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 NG 105 mast section has been specifically chosen for the Dean 498. 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 reducing corrosion. These attachments are custom designed specifically for the Dean 498 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 498, as opposed to the generic drop in heads which are not as strong and robust. The generic heads are also prone to halyard chafe.

The 498’s mast is raked aft by 6 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.

Bridgedeck clearance

The biggest problem with some production catamarans is that they have been designed with low or relatively low bridge decks. There is nothing worse that sailing thousands of miles and every 2-3 minutes hearing a big bang underneath the vessel. This is not good for the crew and in fact this slows the boat down thereby increasing passage time. It was for this reason that when the initial design of the Dean 498 was done the first critical element was “it had to have good bridge deck clearance”. Accordingly it has 1100mm or 3.7ft clearance which by today’s standards makes it one of the highest off the water. This is a good thing!!

No inner forestay- self tacking Jib instead

An inner forestay stops the roller furler Genoa from going around during a tack and each time this is done the sail gets damaged. In light winds it will not go through by itself so a crew member has to grab it and lead it past the inner forestay. For this specific reason we have done away with the inner forestay. The 498 rig still has 2 permanent forestays but they are moved much further forward. The aft forestay has a roller furling Jib on it and control is made very easy by the addition of a self-tacking track situated just in front of the mast. This makes for very easy sailing especially when sailing single handed.

Fixed “Reacher” forestay

Traditionally all catamarans on the market these days have a large sail sticking out on the bow via a flimsy aluminum pole and this sail is referred to as a Screecher. A Screecher was actually designed for the “Americas cup” and to be honest this technology does not belong on cruising catamarans. The main difficulties with a Screecher are furling, removing the “pole” and this sail needs 3 people to control it. It is for this reason that we have done away with the Screecher on the 498 and have opted for the “Reacher” instead. A Reacher firstly has a fixed forestay so furling is made easy. The furling drum is attached to the boat so there are no poles etc and handling can be done by one person.

Wider transoms

A narrow transom allows the stern of the vessel to dig in when sailing. This halters performance and the vessel has no real load carrying capacity so when loaded for cruising the vessel drops down in the water. The 498 has wider transoms which allow good load carrying capabilities

Tanks and engines outside vessel

Some manufacturers have the water tanks and fuel tanks positioned inside the living area. This is not very good practice as there are always fumes associated with diesel tanks and these then come into the living areas which is uncomfortable. On the Dean 498 the diesel tanks and water tanks are situated outside the living quarters so that there can be no small inside the vessel. The diesel capacity has also been increased tremendously and on the 498 carries just under 800 liters. Along with this thinking we have also moved the propulsion engines outside the living areas. This allows for better access, no fumes from the engines can come into the vessel, far less noise inside the vessel and far less vibration is experienced by doing this.

Weight distribution

A vessel that has the engines fitted right at the far aft end and water tanks, Gensets, anchors etc fitted right at the fore end are prone to “hobbyhorse” This makes for uncomfortable sailing and affects sailing performance as the wind is “forced” out the sails by the rapid motion of the boat. On the Dean 498 we have concentrated in keeping the weight as close to the middle of the boat as possible, within reason. Our engines are not right at the back of the boat. Batteries and all other heavy weight items are fitted as close to the middle as possible.

Adequate amount of handrails

Have a look at the brochures of other cruising catamarans of all types and the first thing you will notice is the vast lack of adequate handrails. Some manufacturers have no handrails on the transoms, why, well stainless steel is very expensive as well as labour so why fit handrails. We consider this to be ridiculous and have full length handrails on each transom. We further have solid stainless steel side railings which double as a full length handrail and on top of this have full length railings on the coach roof as well. Certainly no lack of hand rails on the Dean 498

Anchor design

The anchor on most catamarans comes up over the deck and usually this is right next to or very close to the roller furling drum. Usually the anchor touches and damages the roller furler drum. Ugly anchor, chain and windlass are also displayed for everyone to see or to trip over. For this reason we have come up with a different design and one which we use on our bigger Power catamaran the Jag 550. The bow roller, windlass, anchor and chain are all housed under deck and access is via a large opening hatch. This hatch is electrically operated from the cockpit or navigation table. The system also allows for a built in bridle

No ropes or sheets on deck

Our design is absolutely unique. What we have designed on the 498 is that every single rope, halyard or sheet from the mast goes below the mast step, runs through a special conduit in the bridge deck then turns upward at the cockpit and then all ropes, sheets or halyards are led to a huge 3 speed electric winch. This makes for an uncluttered deck and ensures that all sailing activities can be controlled from the cockpit. A true ingenious idea and one that will work well which all other manufactures will follow…….

Kickback on all interior furniture

Traditionally all furniture on any vessel is bonded to the hull and or deck. The vertical sides go straight down and therefore some sort of beading is necessary to hide the joint. Beadings always look ugly and the bottom section of the furniture always gets hurt from shoes and in other ways. We have included a “kickback” at the bottom of all our furniture which automatically creates a “shadow joint”. The furniture looks as though it is floating and nor bonded to the vessel. No beadings are therefore needed and the inside therefore has very clean lines.

Recessed LED lighting

Every single light on the Dean 498 incorporates LED technology. LED lights use 1/10th of the amperage that normal halogen bulbs use and also last 5 x longer. The only places where fluorescent lights are used are in the engine rooms, lockers that need lighting and interior wardrobes. All lighting is recessed (where possible) and all lighting on the Dean 498 can be dimmed.

Large hull windows

The Dean 498 has 6 large non opening fixed windows on the outside of each hull. Aft there are 3 very modern “vertical style” windows (these are located in the owner’s cabin giving unsurpassed views) and running forward to the bow are 3 more windows. These fixed non opening windows give the 498 a very modern look but more importantly allow a huge amount of natural light to enter the vessel. This creates a peaceful ambiance and makes the vessel light and airy inside. There is nothing worse than been stuck inside a catamaran and not been able to see outside or have to rely on overhead lighting for light.

Wardrobes and toilet compartments

On most other catamarans you will find these situated on the outside section of the hulls with the passage on the inside. As we have the large hull windows on the outside of the hulls we have opted to have the wardrobes, toilet compartments etc on the inside of the hull and the passage on the outside. What this means is that when you walk down the staircase to either hull you have a beautiful view of the sea and a huge amount of natural light can therefore enter the boat. Very simple thinking and an idea that all the others will follow when they see or hear about.

Use of sliding doors maximized

Traditionally all cupboard and wardrobe doors have always been hinged doors that open. The problem with this is that the doors when in the open position take up a lot of space and 9 times out of ten, the door when closed never really fit 100%. Doors are also manufactured from wood and wood unfortunately swells or changes size depending on the climatic conditions in the area. For this reason we have decided to maximize the use of sliding doors on the 498. Much easier to open, they don’t take up space in the passage or corridor and are supported top and bottom so the doors cannot change shape. No need to fit those ugly push buttons to keep the door closed either.