Because of the unique nature of Bellatrix -- the project called for a fast, luxurious 74-foot sailing yacht that also could function as a "tender" to and be lifted aboard a world-cruising mothership -- Bellatrix's construction needed to be both light and strong. To achieve this, the yacht's hull, deck, and structural elements were engineered and built utilizing carbon fiber/Nomex honeycomb/structural foam composite construction. Because the yacht's Owner did not want to compromise the luxury or aesthetics of the interior in order to save weight, New England Boatworks used an elegant cherry-veneer paneling with a weightsaving Nomex honeycomb core. To lift Bellatrix to the deck of the mothership, NEB fashioned two carbon-fiber "chainplates."
In order to make sure that Bellatrix fitted to the deck of the mothership, there was much liaison between NEB and the ship builders, as the keel and the rudder fit into dedicated "pockets" welded into the deck of the ship. The pockets have watertight doors to allow routine maintenance to both appendages.
We also ensured that Bellatrix and the mothership had the same electrical power so that when she is on the deck, she can plug into the ship's power. This will allow Bellatrix to be completely operational, prior to launching, because the client wanted the ability to have the freezers cold, the water hot, the batteries charged and the air conditioning running. This also required the use of custom through-hulls to allow the yacht to have her raw-water inlets hooked up to the ships supply in order for the above mentioned systems to run, and custom overboard discharges.
As the ship has the ability to go from the tropics to the high latitudes quickly, the client also required that Bellatrix have exceptional climate control to allow the interior to be comfortable when cruising in freezing Antarctica or the scorching equatorial zone. This was achieved with an elaborate air-conditioning system for cooling and a combination boiler, reverse cycle and electric heating elements for warming the interior.
To make sure that Bellatrix stayed put when going through the weather that the ship would certainly encounter at some point, we fashioned two high-strength custom saddles that were bolted to the steel lifting davits on the ship. These were actually molded from the hull of Bellatrix for an exact match. We also made custom hooks, which fit snugly over the cap rail to which 10-ton ratchet straps were attached. To ensure that any lightening strikes were transmitted through Bellatrix and into the ship's grounding system, we created a steel turnbuckle arrangement, where the pin passed through a hole in the keel. This was a dual-purpose fitting to ground the yacht and provide an additional securing method for the yacht to the ship's deck.
In order to go ashore from Bellatrix, the Owner asked for a jet boat tender. However, to ensure the lines of the yacht were not spoiled by stowing the tender on deck, or slowed Bellatrix by needing to be towed, the designers came up with an ingenious garage door arrangement where not only does the transom open, but the counter actually lowers to allow for easy launch and retrieval of the tender. This is all done hydraulically via a hand held remote. A small hydraulic winch mounted on the bulkhead pulls the dinghy into the garage.
To give the Owner the ability to single-handedly sail Bellatrix and enjoy short-duration family cruises without professional crew, we selected an in-boom mainsail furling system and two roller-furling headsails. The mainsail can be hoisted via joystick actuation at the port helm station, as the mandrel and main halyard "line management system" winch are both hydraulically actuated. Bellatrix also has a hydraulically activated mainsheet, jibsheets and traveler. This allows the helmsman to steer the yacht and set and trim the sails from the helm stations. Bellatrix also has a radar screen and charting screen at each wheel so all the navigational functions may also be accomplished from the helm.
It is rare to get the opportunity to build a true first-class yacht for an owner whose primary concern is quality. Every piece of equipment or material in Bellatrix is the best available for its intended use. Yachts of this caliber are a source of pride to the Owner as well as to us at NEB, but construction of such a vessel is a demanding endeavor. New England Boatworks was challenged to build a light boat that was also quiet. We had to engineer systems normally found in much larger yachts into a 74-footer, and find a way to balance the space requirements of the hull structure and rig with those of the interior accommodations.
Sound deadening requires mass which equals weight. Sailing performance and the requirement that Bellatrix be lifted by cranes onto the mothership demanded a light, strong structure. To this end, we worked with SP Systems which supplied all pre-preg material and engineering for the yacht. The latest raceboat materials and process were used in building the hull structure, but in many cases these materials were covered with heavy material designed to reduce structure-borne noise and vibration. While one may question the use of lightweight materials if they are only to be made heavy, we would suggest that this requirement made high modulus materials even more important, because they still result in a stronger, stiffer yacht with more weight in the keel where it belongs.
Possibly our biggest challenge was that machinery space was at a premium. Bellatrix has transom doors, inverters, a generator, 20 hydraulic functions, a tender bay, a disappearing anchor roller, a large retracting thruster and pushbutton sailing systems normally found in yachts over 100 feet. The challenge of fitting all of this equipment plus adequate tankage in a relatively light displacement hull was a difficult one. Most of the equipment is centrally located under the main salon sole. There is scarcely 700 millimeters of vertical height in this space above the keel structure, so access is tight. We worked very hard at laying out equipment so that it would be serviceable yet compact.
While the above may suggest that Bellatrix's accommodation is rather tight, the reverse is true. There are only two staterooms in the yacht, each with large comfortable heads. Indeed, one has a large bathtub. Passage forward and aft is easy and the main salon is a large, open space. Nevertheless, construction of any cruising yacht and particularly this one, involves careful integration of the structure and the accommodation. For example, the mast passes through the main salon just forward of a fully functioning wood stove. The location of the tender requires that there is no upper rudder bearing in the normal sense, and there is a large passage door 5 inches to starboard of the forward lift point attachment. There is also a hull window inches from the chainplates.
The challenge of the architect, the engineers and the builder is to balance requirements that often conflict. That all of these challenges were successfully met is what makes Bellatrix a unique sailing yacht.