Quality & Performance

Apollonian Yacht Under Construction

Apollonian Yachts aren’t just finely finished and packed with features and accommodations; they’re also designed to be rugged, reliable, and long lasting. After years of careful planning, preparation, and construction, new boats started arriving in North America in 2020. Built to exacting standards, the main deck is one continuous part that encompasses the transom, outer stairwell, cockpit, salon floor, stairwell from salon to pilothouse, and the pilothouse itself. The deck and hull are crafted using closed cell cored vacuum-bagged and infused fiberglass and vinyl ester resin construction. This method minimizes deck and hull weight while also increasing strength, while the vinyl ester resin eliminates osmosis.

Complementing our durable hull designs, the engines are carefully placed within the hull to optimize performance. Twin aluminum fuel tanks run athwartships ahead of the engines, creating a dividing bulkhead that keeps engine noise away from the cabins. The positioning of the engines also provides weight and balance advantages, keeping the boat’s center of gravity low for improved seakeeping. The Apollonian 52 uses ZF2.5/1 gears, straight 2 1/2” stainless steel shafts with PYI/PSS Dripless shaft seals, bronze I struts with cutlass bearings, and 30×24 NiBrAL 4 bladed props. A low shaft angle of less than ten degrees increases overall performance and efficiency by directing engine power directly to the props without torque losses associated with the additional gears used in pods or V-drives. The boats are easy to maneuver with a standard Vetus bow thruster that can be used in combination with the twin engines and shaft drives. Benefits of shafts include their consistent performance and reliability along with lower overall costs from initial installation throughout the lifetime of the vessel. Pods and joysticks simply cost more, and experience tells us that there is little return on that investment in vessels like those built by Apollonian Yachts.

Apollonian Yacht being lowered into the water.

Each Apollonian is meticulously crafted using the best possible materials and they are carefully fitted with high quality equipment and components. Designed by boaters for boaters, access to engines and systems are carefully considered throughout. Analog gauges at the pilothouse helm in addition to the digital read outs on the MFD’s, fuel fills on both sides, a convenient waterproof pilothouse door leading to the wide and well protected side deck, and a centrally located day head, are a few examples of the care given to the functionality and systems on board.

Apollonian Yachts are designed by renowned Northwest naval architect Howard Apollonio and constructed on an innovative and efficient new hull he created. Collaboration with experienced yacht salesman and life-long boater Vic Parcells adds practicality and functionality to the boats. Knowledgeable boat owners and buyers will appreciate the combination of modern design and equipment, with purposeful systems, well thought out accommodations and tasteful nautical styling.

Performance By Design

The hull form used in Apollonian Yachts benefits from many years development and applications in commercial and military uses, including some unique innovations to enhance comfort and overall performance.

The split-chine, semi-planing, semi-displacement hull of the Apollonian series represents the use of fine technology and modern design. It fulfills the basic mandate that naval architect Howard Apollonio has incorporated over his 41year career: high efficiency combined with exceptionally good sea-kindliness.

Comprehensive model testing proved the point so successfully that no examining of further variations was needed. Efficiency beyond target values was demonstrated, along with unparalleled low motions and vertical accelerations for the speed ranges of interest, in a boat this size. This design was the result of a fruitful collaboration with a fellow designer and hydrodynamicist who has extensive experience with these types of hulls.

Apollonian Yachts’ mission was to operate efficiently as a long-range cruiser in the 10- 12 knot range, yet also maintain that efficiency at speed of 16-18 knots and faster. Performance, particularly at mid-range speeds can be affected by the pre-planing resistance hump, which can cause operational challenges. The approach was to use features of both displacement and planing hulls each to their best advantage. The resulting hull has what appears to be a classic fine-lined round-bottom hull in its forward 1/3; but with a prominent spray rail well above it. The spray rail performs a chine’s function of controlling the main-spray and high-pressure zone where hull first meets waterline underway.

Careful forming of the transition between spray rail and hull was important to create a clean spray pattern and maintain a soft ride. The aft 2/3 of the hull has a hard-chine semi-planing form with a wide, shallow stern to resist squat, while letting water exit aft with minimal fuss. Integrating the propeller tunnels smoothly into the development of this hull form helped make this work better. This hull shaping process, combined with balancing the boat dynamically, is a very tricky process. It proved worth the effort, as the model test demonstrated. An added benefit of the chine diminishing as it goes forward, is that at rest it does not create any chine slap from waves, a common annoyance that occurs on many hard chine hulls.

A keel of modest depth provides stability and protection without compromising turning behavior and allows for shallow draft (under 4 feet). Even though this hull has a high displacement/length ratio of 177 to 281 as-model-tested, its fineness gave it the efficiency and ride quality sought. The hull’s prismatic and block coefficients of 0.67 and 0.35, respectively, are keys to this result. Carefully blending this with a relatively high beam-to-length ratio of 0.29 and 0.32 maintains high stability with metacentric height, GMt, of 4 to 5 feet. In rough water testing, this hull gave better results (lower motions and vertical accelerations) than a highly refined yet much larger vessel in the same sea state. Significant (average of 1/10 highest) vertical accelerations were comfortable 0.34 to 0.47 at 8 to 20 knots in sea state 4. The deck stayed dry in all cases. Most boats in this size range stay home by necessity when it gets as rough as sea state 4 (6 foot + significant wave height) but the Apollonian hull form allows it to safely navigate even in rough conditions.

The split-chine hull design of Apollonian Yachts meet today’s challenges of efficiency, long range, and superior sea kindliness, necessary for extended passagemaking at moderate speeds, without sacrificing the ability to cruise efficiently at high speed.

(This is an overview of a response that Howard provided to an interested party that wanted to better understand about the Apollonian Yachts hulls being cored.)

Howard Apollonio:

I became involved in advanced composite structure design as a navy contractor in the early 1970’s. After 12 years in military and commercial craft, I got increasingly involved in yacht design, while still involved with navy and commercial. I am a licensed professional engineer in WA state. Construction and materials are major issues in my work, which, is quite varied technically. I have adopted significant developments in composite engineering as it has evolved in this industry; and know when to apply simple or complex approaches to it.

Advances in materials and construction methods allow modern builders to construct cored hulls and decks that have capabilities superior to solid panels. When coring was first used in the 1960’s ’70s and early 80’s, mistakes were made, but modern applications and techniques have proven the merits of coring. Benefits of properly constructed coring include weight savings, insulation of both sound and heat and durability. Most major boat builders and design engineers now have a good grasp of composite applications and practices. Many boat builders of large yachts both internationally and in the U.S. use and are comfortable with cored composite construction, having learned the right way to do it. I have direct experience dealing with several, including Westport and Christensen, building very large cored composite vessels.

The Apollonian 52 benefits from these developments and experiences. Their teams of laminators are specialist that know and utilize the proper techniques of applying the materials which when done properly are not complicated. I prescribe simple aspects of the technology that includes knitted unidirectional glass reinforcement in vinylester resin as double skin plating over rigid elastic Divinycell core material. The moderate flexibility of each material is matched to each other to produce exceptional toughness to resist bashing from waves and rocks. The resin is not only stretchy, but also impervious to water intrusion. The process of lamination includes vacuuminfusion of resin reliably throughout the reinforcement material. I have seen cases where this tough double-skin construction has saved a hull in situations where single skin laminate would transmit damage thru the laminate to the inside of the hull (and even sank a prominent 70 ft trawler yacht with a 3″ single skin bottom).

Howard R. Apollonio, PE, Naval Architect and Marine Engineer

Benefits of modern composite construction:

  1. Weight savings
  2. Increased strength for the given weight
  3. Better Insulation (both sound and heat)
  4. Puncture resistance
  5. Less ability for damage to spread through the structure
  6. Increased rigidity or flexibility depending on how the materials are used


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