First U.S. Ferry Equipped With Cycloidal Propellers Set For Service Debut
Some of New York City's harried mass transit users will have something- to look forward to this month. The first of two new ferries, the Andrew J. Barberi, is scheduled to enter service between St. George, Staten Island, and the Battery, on the tip of Manhattan.
To the maritime community, the most interesting aspect will be the results of the first use by a ferry in the U.S. of a cycloidal propeller system. Cycloidal propellers were chosen, explained officials of the city's Bureau of Marine and Aviation, because they want to reduce maintenance costs for the racks at both terminals. The 5.2-mile ferry route from Staten Island crosses the main ship channel of New York Harbor. When approaching Manhattan, the ferries round Governor's Island at the south end of the East River and steer toward the slip. Under unfavorable tide or wind conditions the approach may be made at an angle of almost 45 degrees. At present, after touching the pilings at this angle, power is applied and the vessel drags along the racks until it reaches a position suitable for mooring. The racks, systems of interconnected wooden p i l i n gs bracketing the ferry slips, suffer a great deal of impact and rubbing from the docking of the currently used ferries. Powerful tidal currents from the confluence of the East River and Hudson River, and from the Narrows, or adverse winds, can shove a f e r ry sideways into the racks, resulting in annual rack maintenance costs of approximately one million dollars. The superior low-speed maneuverability of the cycloidal system should reduce the cost, officials state.
The 5,900-dwt d o u b l e - e n d ed Barberi was built at Equitable Shipyards Inc., New Orleans, La. The vessel is provided with two 3,500-horsepower cycloidal propellers from J.M. Voith GmbH, Germany.
A second ferry, with the same propulsion, is being completed at Equitable.
The Barberi is 310 feet long, is 65 feet wide at the waterline, and has a d r a f t of approximately 12 feet 6 inches. The increase in freeboard over existing ferries indicated a potential for delays at the Staten Island terminal during extreme flood tides. This necessitated that the new vessels be provided with a ballasting system capable of transferring 35 tons of ballast water between the trim tanks in 25 minutes.
The basic design was developed by George G. Sharp, Inc.
However, city officials added an a l t e r n a t e incorporating Voith- Schneider cycloidal p r o p e l l e r s. The vessels' lines were developed by the propeller manufacturer to meet the requirements for their use, which necessitated that the midship section have a high deadrise and bilge radius, while forward and a f t the bottom flattens. The hull is symmetrical about midships. Skegs are fitted forward and a f t to provide directional stability, to protect the propellers from floating debris, and to facilitate docking.
Four GM 16-645E diesel engines provide the main propulsion, each delivering 1,750 bhp at 800 rpm. Engine power is delivered through a turbo coupling and a lineshaft system inclined at 4.2 degrees from the engine room to the fore and a f t propeller units. The couplings and lineshafts turn at engine crankshaft speed. The propeller has a builtin double input reduction gear with a 13.7:1 ratio, consisting of pinion gears on each side of the propeller which drive a ring gear through a bevel gear and give a rotor speed of about 57 rpm. The blade orbit diameter is 4 meters and each rotor is fitted with five blades each 2.4 meters long. The blades are hammer forged from c h r o m e nickel stainless steel, milled to the final shape from a model blade, and subsequently ground to final finish.
A conventional propeller produces thrust perpendicular to the plane of rotation of the blades. The propeller rotates in a vertical plane while the thrust is horizontal; this thrust is deflected by a rudder to steer the vessel. A cycloidal propeller rotates in the horizontal plane; that is, parallel to the vessel keel, and still produces horizontal thrust, a force which can be directed through 360 degrees by adjustments to the pitch of its vertical blades. This adjustment is accomplished through a mechanism in the propeller housing, eliminating the need for a rudder. This results in the ability to provide intricate low-speed maneuvering, a prime consideration for use in the New York ferry terminals.
Each ferry is equipped with two interconnected pilothouses and control can be directed from either, but not from both simultaneously. The switchover from one pilothouse to the other is t h r o u g h a direction indicator above the main engine room control console. This console is housed in a control room located in the engine room. The control room is soundproofed and air-conditioned, and has windows that provide the engineer with an overall view of the engine room.
There are three control modes for the propellers. Normal operation is by remote electric control from either pilothouse. This is backed up by control from the engine room via an electrical propulsion and steering order transmitter to a manual /hydraulic remote override of the servo valves on the propellers. There is also the option of using an emergency manual control on the propeller units, the crew being guided by telephone from the pilothouse. Each pilothouse has two steering wheels; each controls the transverse pitch on one propeller. Under free route conditions steering is by conventional use of the stern propeller. During maneuvering for docking, the helmsman can control bow and stern p r o p e l l e r s independently. Each wheel has an order indicator and an answer-back indicator. The ahead astern speed is regulated by a pair of levers which control the amount of ahead or astern pitch on the bow and stern propellers. These adjacent levers permit the operator to use one hand to control both propellers simultaneously.
The $15-million Barberi, named in memory of a former football coach in Curtis High School on Staten Island, N.Y., was fitted with a protective false bow and stern for its ocean voyage from Equitable to New York. She arrived on August 7 and entered drydock for inspection, testing, and training of the crew in the use of the cycloidal system before acceptance by the city.
The diesel-powered Barberi and her sister ship, the Samuel I. Newhouse, will replace three 33- year-old steam-fired ferries. The timetable allows for a 30-minute crossing, which includes loading, unloading, the voyage, and intricate docking at the ferry slips.
About 50,000 commuters use the ferry system daily. The new ferries are exclusively for passengers and can transport 6,000 people, with seating for more than 3,700.
The Andrew J. Barberi achieved a sea trial speed of three to four knots faster than the design and the model test speed, at the same horsepower and at full design load. Consequently, she is expected to travel regularly at a reduced rpm.