NAVAL ARCHITECTURE & HULL DESIGN

OYD has designed numerous hull forms for commercial vessels, government vessels, and yachts. All too often, a basic hull form will be recycled over and over rather than creating the optimum shape for each, unique vessel type. Time constraints, R & D costs, and experience, or lack thereof, are usually the deterrents to creating an optimized hull.

We optimize the hull form for the intended purpose of the vessel. From displacement to planing, from hard chine to round bilge, with or without a bulbous bow. Two decades of experience gives OYD a multitude of highly refined, proven hull forms to choose from when starting a new project; nine are displayed here.

Aside from creating our own hulls for OYD's in-house designs, we also offer our hulls to clients that may already have their own stylist or designer who desire a proven hull form for their new project.

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Overing 37 Meter Trideck Explorer
Full Displacement Chine Hull

Inace/Kirschstein 41 Meter Trideck
OYD Full Displacement Soft Chine Bulbous Bow Hull

Mariner 30 Meter Pilothouse Motoryacht
Fast-Displacement Round Bilge Bulbous Bow Hull

Dauntless 31 Meter Pilothouse Explorer
Fast-Displacement Round Bilge Bulbous Bow Hull

Overing 31 Meter Trideck Motoryacht
Semi Displacement Chine Hull

Overing 37 Meter Trideck Motoryacht
Semi Displacement Chine Hull

Overing 53 Meter Trideck Motoryacht
Fast-Displacement Round Bilge Bulbous Bow Hull

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Our pinnacle hull form and most noted is our highly acclaimaed "fast-displacement" hull. In 1998 Overing developed his first fast-displacement (FD) hull form. His objective was to rewrite the rules and create a new benchmark of efficiency, comfort, performance and seakeeping. In order to achieve these goals the full displacement hull speed rule would have to be thrown out the window.

Overing's outlook was if man wrote the rule, man can rewrite the rule. The end result of Overing's creation are full displacement hull forms that have a speed/length ratios of 1.65 to 1.70 clearly redefining the long standing displacement rule of Velocity =1.34 X the square root of the waterline. While Overing is not the first to exceed this threshold, what sets the OVERING FD hull apart from other top performers is the generous beam, depth and displacement maintained throughout the full range of FD hulls.

Most anyone can can achieve good speed and efficiency with a narrow, lighter displacement hull, but try to achieve high marks in a beamy hull with good depth and displacement. This was the real challenge! Sacrificing beam and depth can never be an option as the yacht would lose it's market appeal due to loss in interior volume.


Some ask "why try to make a full displacement hull go fast?"

Some key benefits are:
1. Full displacement hulls are, in general better sea boats as compared to semi-displacement or planing hulls.
2. Weight is not as big of a concern since you are not trying to lift the hull.
3. Full displacement hulls inherently have more volume providing more accommodation space and fuel capacity within a comparable size.

Overing's philosophy was - if higher cruise speeds can be achieved with modest horsepower further refinements then can be incorporated to reduce pitching and roll thus creating the perfect motoryacht hull. Historically, many are turned off by the typified full displacement yacht due to it's slow cruise speed. As example, a typical run-of-the-mill 90 to 100 foot full displacement yacht will cruise around 8-9 knots economically. Speed up to 10 knots and the economy starts a notable drop. Generally top speed is only in the 12 to 12.5 knots range with a fuel burn of 55 to 60 GPH.

This ho-hum performance has little broad appeal. Our 30 meter FD hull cruising in the 10 - 13 knot range consumes about 40% - 50% less fuel and tops out around 14 knots with the same horsepower. Increase horsepower and the cruise jumps to 14-15 knots with a top speed of 16 knots. Over the past four years our 30 meter FD hull has logged over 35,000 NM and exhibits a very comfortable ride in 6 to 8 foot seas at 12 - 13 knots.

These highly evolved round bilge full displacement hulls were named by Overing "fast-displacement" and copyrighted by OYD in 1999. The FD hulls well exceed the displacement rule in performance while generating zero lift as speed is increased. The result of the high efficiency is an extreemly comfortable, sea kindly full displacement vessel that will cruise economically where other vessels are at maximum hull speed burning twice the fuel.

We now have proven FD hulls ranging from 73' up to 174'. Our 98 long ton 73' FD hull will cruise at 10.5 knots burning just 16 gallon per hour and top out at 14 knots realizing a speed/length ratio of 1.67 with just twin 500 bhp diesels. Sea trials of the 73 revealed a comfortable ride in 6'-8' seas while effortlessly maintaining 10 - 12 knot cruise. Our larger versions in the 45 to 50 meter range will easily cruise at 15-16 knots and exceed 20 knot top speed with reasonable horsepower. We limited the 50 meter hull test to 21 knots and interestingly enough the hull had yet to reach its hull speed still void of squatting with a very shallow running angle.

Now on our fourth generation and over 15 years of continuous refinements, our "fast displacement" hull is second to none in seakeeping and efficiency when compared to other hulls with similar length/beam ratios and displacements. Yachts we have designed and built with this superb hull form have accumulated hundreds of thousands of sea miles and some cruising to the farthest corners of the world.

ALLEGRO 24 Meter Pilothouse Explorer
Fast-Displacement Round Bilge Bulbous Bow Hull

Overing 30 Meter RPH Motoryacht
Fast-Displacement Round Bilge Bulbous Bow Hull

Overing 31 Meter RPH Motoryacht
Fast-Displacement Round Bilge Bulbous Bow Hull

Dauntless D73 - - 22 Meter Pilothouse Explorer
Fast-Displacement Round Bilge Bulbous Bow Hull

OVERVIEW

OVERING FAST-DISPLACEMENT HULL - THE DESIGN AND BENEFITS

Overing 22 Meter RPH Motoryacht
Fast-Displacement Round Bilge Bulbous Bow Hull