BD Yachts – following the January 2016 presentation of the innovative BD56 project, TiàSimó, Naval Architect and Managing Partner at BYDGROUP – naval architect and designers ofBD56 – provides us with more details and further clarifications based on the questions received over these last few months.
BD56 ENGINES
Being a very unique boat, the BD56 (designed and engineered by BYDGROUP) has very specificneeds in terms of propulsion that conventional sailing yachts and conventional motor yachtshave not. Whiledeveloping the project, the BYDGROUP team found that the inboardpropulsion systems available were inefficient for the BD56’s particular design. For a high speeddesign, high thrust propellers are required, but they are unavailable in a folding version,necessary to reduce drag when sailing. Retractable propellers were another possible solution,but they are technically complicated and have reliability issues, as well as being very costly dueto necessary customization.
With this specific yacht BYDGROUP needed the most efficient and convenient propulsionsystem available on the market, requiring reliability, ease of use and maintenance, a sufficientpower to weight ratio, and very importantly, a way to reduce drag from submersedappendages: shafts, struts and propellers. The result was unexpected – outboard engines!With thrust at a 0º angle to the DWL with an outboard engine, the drive applied by thepropeller is equivalent to the drive applied by a conventional shaft at a 10º angle. In addition,the possibility of changing the thrust line angle provides for even greater efficiency.
Given the low weight of the outboards, the position of the CoG in balancing the hull with driveapplied from the stern is equivalent to that of a conventional inboard configuration.
The engines are hidden in the transom of the boat below the deck, well ventilated and withsufficient space to be lifted out of the water when sailing.
The power available for this boat is either one 200 hp engine (11,5 Knots Max) or two 350 hpengines (21 Knots Max).
Why?
-Easy to install and maintain
-Fantastic maneuverability by joystick
-High global reliability
-Parts & maintenance available worldwide
-Easy to lift the engines out of the water, thus removing any added resistance
-Reduced weight
-Weight to power ratio of the whole propulsion system is apx. one HP per kilogram.
-No need for a complex engine room
-Electronic control systems for docking the boa
Although Mercury motors are proposed by the yard for the initial release, one of theadvantages that currently offered by BD Yachts is that the owner can choose any leading motorbrand available globally: Yamaha, Honda, Suzuki Marine, Evinrude, or Seven Marine.
TESTS OF CFD, RESULTS, RELIABILITY, EXCELLENT PERFORMANCE…
In order to validate such a unique design, BYDGROUP and BD Yachts invested time andresources in the most advanced calculation and prediction technology – CFD (computationalFluid Dynamics) – to analyze the performance of the boat, both when motoring and under sail.
The naval architects TiàSimó and Raul Gonzalo designed more than 20 different hull modelsand configurations that were tested in a virtual Towing Tank, where real conditions weresimulated. For the calculations BYDGROUP worked with a specialized team with Volvo OceanRace and America’s Cup experience, Cape Horn Engineering: the accuracy of the results iswithin 5% of the theoretical design data. Their experience in the optimization and analysis ofplaning sailing yachts is a warranty for success. With the help of CHE, BYDGROUP developedan optimal design giving the best performance both under sail and under power.
PRICES AND DELIVERY
The BD56 is a tailor made product, built considering the needs of their future owners inmultiple configurations, colors and finish qualities, to meet the demands of the most demandingyachtsman, and therefore yard does not have an exact price.
A full option BD 56 with a five (5) year warranty & maintenance service has an estimatedprice of 2.2 million euros. Delivery time for the first unit is 15 months.
