Propulsion News

PBCF Aids Propulsion Efficiency Propeller Boss Cap Fins (PBCF) is a propeller enhancing device, which is designed to cut fuel consumption and exhaust gases by up to five percent while incurring no additional maintenance cost once installed. The unit, according to H. Yumoto Manager of PBCF Div. Mitsui O.S.K. Techno Trade, Ltd., is now operational on 720 ship worldwide. The PBCF rectifies the propeller hub vortex and recovers rotational energy otherwise lost in the propeller slip stream. Increasing propeller thrust by over one percent and reducing propeller torque by over three percent, the PBCF reportedly results in fuel savings of up to five percent or compared to vessels operating at equivalent speeds but without the PBCF, alternatively, a 1.5 percent increase in speed at the same engine output.

The PBCF is designed to eliminate propeller hub vortex, resulting in reduced stern vibrations, propeller noise, and noise contamination in marine acoustic equipment. It also reportedly resolves a number of rudder erosion problems.

The PBCF is a boss cap with fins made from the same material used in conventional boss caps and installed in the same way. This means the PBCF, like conventional boss caps, does not require additional maintenance once fitted, and can be easily replaced. A number of vessels, (oil tankers, containers, etc.), have been retrofitted with the PBCF whilst at sea.

When replacing conventional boss caps with the PBCF, no shaft design reviews are required by classification societies such as AB, CR, GL, KR, LR, NK, and NV.

About 40 percent of PBCF's sold to date have been retrofitted to running ships, the remainder have been fitted to newly built ships. By installing the PBCF at either the ship building stage, or during shaft inspection for running ships, extra shipyard costs can be avoided. The PBCF was developed jointly by Mitsui O.S.K. Lines, West Japan Fluid Engineering Laboratory Co. Ltd., and Mikado Propeller Co. Ltd., and is now patented in 12 countries. In 1994, the sales right of the PBCF was moved from Mitsui O.S.K. Lines (MOL) to one of her subsidiaries. A few subsidiaries have held the sales rights since then, but in April this year Mitsui O.S.K. Techno -Trade Ltd., PBCF Division took over responsibility for sales of the PBCF. Through license agreements, Mikado Propeller Co. Ltd., Nakashima Propeller Co. Ltd., and Samsung Heavy Industries Co. Ltd. have a restricted license to sell and produce the PBCF. Mikado Propeller Co. Ltd. has sold around 310 units, primarily to smaller domestic vessels including pleasure and/or fishery boats. Nakashima Propeller Co. Ltd. has sold 9 units to mainly medium sized vessels, and Samsung Heavy Industries Co. Ltd. has sold 9 units to larger sized vessels. Lynn Gear Plant Upgraded

GE Marine Engines will invest in substantial upgrades to grinding, inspection and hobbing equipment used at its Lynn, Mass., Gear plant over the next year. The first production pieces to be produced with this new equipment will be high-speed pinions and gears for the U.S. Navy's current DDG destroyer program. "We've taken a 20-year step forward with this large investment in new equipment, which translates into long-term value such as greater grinding accuracy and gear reliability," said Bill Gehr, manager Gear Programs for GE Marine Engines. "With this sophisticated technology, GE will be able to produce quiet, more reliable gearing with enhanced load capacity by holding tooth tolerances within .00005 inches — about 1/60th the size of a human hair." The new CNC form grinding equipment replaces the generation grinding equipment GE installed in the 80s. This high precision machine will enable the use of a CBN cutting wheel technology to profile grind marine gearing.