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TANTON 45' Cat-Ketch. Design # 842 in the"Catalogue".




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Talking about commitment to a concept, back in 1983 and with some 30 or 40 Tanton 43's launched and sailing all over the world, it was felt that the syndrome of "one foot more" was creeping and winning. Not the only reason but one as good as the usual excuses of: the molds are getting old: it would be nice to have a larger aft cabin; we can use the new Nytex material, etc. Well briefly, all these reasons good bad and indifferent led to a new design and a new boat. New from the ground up with many refinements over the 43 but not entirely different to upset the delicate but successful characteristics of the previous design.

Strangely, no consideration was given whether this new boat was going to sell better, be more popular, and be faster than the 43'. Its sounds like we were totally ignorant or looking after the Holy Grail all together. No. Simply we knew that: if we could spend more time, more money, more technology, we would ultimately be the only on in the Cat-Ketch world to survive and therefore win. Nobody could possibly, without going broke, mad or totally demoralized, go through the effort again to produce a Cat Ketch of this magnitude. Well, it looks like we have succeeded in all departments including being left alone. I do not see any competition on the horizon. The public at large never followed, being more interested in their Marina Cocktail Boats. That is fine we have nice boats and enthusiasts owners. The reality of their boats is here.

Ok. Let's go back to the boat. With a bit of advice-first to the potential client, student of architecture, or simply to the onlooker-there is a key to yacht design, and this is "keep the waterline long". This is a waterline design, a flat out cruising machine.

You will be amazed to see what it does to the numbers associated to the yacht calculations and, therefore, to the performance of the boat. Let's have a look:

The displacement is associated with the longest waterline of 40'-6 1/2" and gives a displacement length ratio of 173.8. Not bad. Especially if one considers that this is better than all except a few flat out racing boats with no interior, questionable construction, and no comfort whatsoever. The result is a very fast sailboat if associated with the other magical number: the sail area/displacement ratio. More on this later.

With a long waterline for a given length, of course we end up with short overhangs. I will always remember the remark of Joshua Slocum when asked about the lack of overhangs on his famous Spray. "In the Gulf Stream with a strong Northeaster, you do not want long overhangs." So be it.

Bow and stern configurations are very much part of the design concept of this Cat Ketch. You see, with a mast so far forward, it is imperative to keep the hull volumes up. I mean really up, to avoid hobby-horsing and going nowhere. Therefore, the bow is of what I call a" modified spoon bow" design. Very sharp at the waterline but then flaring up to very strong voluminous deck lines. Well by now you must understand that there is a reason for everything on this boat. At least that's the way I see it. This is why I want to describe her stern. Next.

I like double-enders. Reminiscent of my "Colin Archer" years when as a little kid, I was designing the husky Norwegian rescue boat on every school book and piece of paper I could lay my hands on. Obviously, this is not the only reason, but I feel strongly that the stern is one of the nice features of this design. Much, much fuller and powerful than usual, I term the stern as a "rounded transom". Some people have said it gives the boat a pregnant look, but I defined this remark by stressing in any case the purposeful aspect of the situation. One decision on this new Cat Ketch had to be to keep the stern of the 43 because it is safe and powerful with lots of volume and fast. All hull lines are wonderfully faired in above the rudder skeg and are the logical extension to the shape of the midship section.

The midship section is typical of my work for cruising boats. I believe that if you give me just under two feet of hull depth, a beam waterline of eleven feet, and a high prismatic coefficient (that stands for full ends) I can build, within this envelope, just about any accommodation plan for boats from 35 to 105 feet. And I have done so.

The lines plan shows a hull fitting the above description with full ends, flat midship section, deep bow sections and very fair lines all together.

A point of discussion is the rudder and the keel. Both are, as in any modern boat, clearly separated from the main body. Their functions are totally dedicated to their different roles: stability and resistance to leeway in the case of the keel and direction and control in case of the rudder. Let's start with the rudder. It is a fact that the rudders with frontal skeg work better. It is also a fact that on a racing boat, the extra wetted surface is not tolerable. But why do we see so many cruising boats with a spade rudder configuration? I believe it is because it costs a lot more money to properly build a rudder with a skeg. First you have to increase the area of glass; you have to cast a heel fitting; you have to place stainless steel reinforcement into the skeg and obviously attach the whole thing to the hull. Of course the added skeg protection is a must for any respectable cruising vessel. I do not know if you noticed yet, but the whole idea of this sailboat is to be a real sea boat, not a pseudo cruiser, nor a Madison Ave. glossy concoction. I hope I make my point clear.

Now about the keel! A draft of less than five feet and no centerboard is sort of unique for a vessel of this size. But this lack of depth is appreciated and rendered possible only because of the Cat ketch rig built with very light carbon fiber masts. This is only a roundabout way of saying that the rig in this case had tremendous importance in determining most of the reasons why this boat is the way she is. The keel adopted is moderately long with a NACA foil section faired into a flattish body in order to enhance the keel aspect ratio. The back end of the keel and the rudder is "relieved" at the bottom to make the trailing edge less vulnerable to grounding. A disgression to say that I have had a lot of experience with wing keel and this configuration would have been the choice for stability reasons, should the boat had been fitted with "old fashion" ketch masting and rigging with spreaders and wires. Why, because the weight of this "normal rig" would be three times the weight of its carbon fiber counterpart; therefore, we would be scrambling to get this boat on her feet; and depth, draft, and wings are a good way to control stiffness under sails. Nobody wants to sail heeled over.

Well, it is time to consider the real question. The cat ketch rig is the reason and the heart of this boat in terms of stability, performance, and ease of handling. The spars are made of unidirectional, individual composite carbon fiber filaments. What is unique is the fact that with computers, we achieve complete control over the fiber direction angles, and with a majority of 0 & 90 degrees, the strength of these poles is maximized. Literally indestructible. I believe the boat would disintegrate before the mast would break. Well this is quite a statement, but in reality our experience has shown that so far the results have been above our expectations. The diameter is less than 10 inches at the base tapering to 3 1/2" at something like 62 feet above the waterline. All fittings are stainless steel and placed on bands to fulfill the different functions, controlling the halyards, wishbone, etc…The wishbones are an ideal means to handle everything at once with a minimum of effort. Simply said, take a windsurfer; replace the wishbone by a boom, and you will see that it does not work because the amount of effort you would have to put in just to keep the boom down is horrendous. The wishbone does it all naturally. All the forces are working in the right direction. Besides, the sail shape is perfect from top to bottom and unhindered by spreaders, shrouds, etc… This reason alone explains why these boats are so fast downwind with no spinnaker. Everything would be perfect except for the fact that the public has a tough time to understand, and get used to the idea of wishbone instead of booms. You see, when you sell a cat ketch, you not only try to sell a boat (hard enough), but you also have to sell a concept (and that is very difficult). Well, the next step is to work on rotating carbon fiber masts and wishbones that look like booms but are not. Which leads me up to talking about the sail plan and the sails.

The sails come either soft or with battens or a combination. Clearly, the added horsepower of the full battens is awesome, but so is the weight, (to hoist), the cost etc. Let's say that I always try to give a high sail area displacement ratio to start with. In this case, the number is 18.33 for soft sails, and I reckon 20 for fully battened sails. Something weird is happening though. The Tanton 43 is the same. You know that you have to have a certain amount of lead that is a certain spread between the center of lateral plan and the center of the sail plan. Well on this design, both coincide, and the boat sails! I have to admit, I was a little bit nervous when try this for the first time. Obviously, there is nobody to talk to about such heresy, but it works. Not only that, but the boat goes up and down wind with all kind of combinations and with perfect balance. Well there are still a few mysteries in the world of sailing.

Let's study the deck now. It's funny, but I do not receive too many phone calls from winchmakers (nor from sparmakers and sailmakers for that matter). I can only disappoint them. Suffice to say the gallery show that three winches and a few stoppers control all the lines. Simple enough. The only drawback of having so few winches is once in a while the need to have extra help for handling dock lines, For instance, I would suggest getting a vertical windlass with the boat. That's it for sail handling.

Now the cockpit. It is the nerve center, the lounge area, the tanning salon, the Jacuzzi, and God knows what else. The table can seat eight to ten people around a drop leaf table. Inside the table you have added room for a gas bottle and also a liferaft. There is not much need on this boat for sail storage. Therefore, the seat locker offers places for all the impedimenta of cruising gear.

Behind the large steering wheel, we have access to a stern ladder. Hot and cold shower is available in this aft part of the cockpit, for washing off the beach sand! A dodger protects the forward part of the cockpit. There is plenty of room on deck to locate a dinghy, windsurfer, etc. The two deck lockers forward are convenient for lines, fenders, anchor, hoses, etc… The roof is a bit voluminous, but obviously, we wanted a very nice interior with plenty of light. This is where we are going next. Down below.

I guess it is always difficult to be different, but I should say the dare was to do it. With the boat, with the rig and why not the interior. Before speaking about the accommodation, I would like to say a few words about the construction of this boat.

The construction features a grid molding for the floor system. Sandwich core material is molded in above the waterline for insulation and stiffness. This allows through hull fittings to be placed in solid glass areas. The fiberglass is Nytex and set in isophtalic resin for 50 % of the layers to avoid blisters. All bulkheads are structural, and added beams in ways of the large deck panel sections and masts. This is in essence, the base of construction.

I am going to breeze through the interior, as I am running out of time and space, also because the gallery I hope are self-explanatory. Suffice to say that what is not shown on the gallery are locations, pre-set for most contingencies we are faced with to install into today's boat: the extra batteries, the watermaker, the compressor, the hot water heater, the extra tank et… Well, there is room for everything or just about. The companionway is offset to port instead of the conventional starboard side. One reason I can think of is to have more elbow room for turning winches on deck. Another reason is that the regular maintenance points of the engine are on the starboard side. Coming down the ladder, you will find quarter berth and navigation area to port. Owner's cabin to starboard. This cabin is very large, roomy and contains a hanging locker and drawers, plus storage. Further forward, you have direct access to a separate shower and toilet area. On the port side again, the large galley features a gimbaled stove oven and drawers, very useful at sea. Built-in buffet will fit a Norcold standing refrigerator if wanted, or a set of drawers and a locker. Behind this buffet are batteries placed a short distance to the electronic navigation area and also to the engine located in the middle of the boat. The main salon presents the usual settee with table. Across the way are two built-in captain chairs. By removing their bases, you can transform this area into a settee with a pilot berth above. In turn, this pilot-berth can be switched to closet space, should the customer want something different. Walking forward again, we have a toilet compartment with separate shower. Access from the saloon or from the forward cabin is provided. The emphasis is on privacy. I tried to match the forward cabin in comfort with the aft cabin.

I hope this interior will appeal to the market and the boat as a whole to the sailor.




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Here are just a few of the comments received about Tanton from professionals in the trade:

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"Yves-Marie de Tanton is one of the great designers but not exceedingly well known outside the trade. He pioneered the unstayed carbon fiber Cat-Ketch rig. He specializes in the sort of intensely personal custom designs that keep his customers coming back."    S. C. B.

"Yves-Marie is a very talented designer with lots of fresh ideas, a guy worth keeping tabs on."   D. S

"Tanton has designed some of the world’s fastest and most exotic racing yachts. This gives Tanton a most unusual perspective on design features for esoteric cruising boats."  R. H.  P.

"I had the pleasure of working with Yves-Marie when I was on the East coast. I must say that my own drawing style and design approach was markedly influenced by the six months that we worked together. Yves-Marie probably draws the fairest set of lines that I have ever seen. His lines gallery are truly works of art."  B. P.

"Tanton has never been accused of surrendering to convention."  Q. W.

"Tanton has already designed five boats for me and currently designing two more. This speaks for itself."  B.  G.

"Tanton had met the criterion creativity and had offered a highly professional design that would provide a two-person crew a uniquely capable world cruiser."  B. W.

"Un Franšais, Yves-Marie TANTON, s'est installÚ Ó la Mecque des U.S.A. : Newport. Il compte parmi les meilleurs."   G. R-D



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