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Frequently Asked Questions | PBCF| PBCF | MOL Techno-Trade, Ltd.

The most Reliable Energy Saving Device - Propeller Boss Cap Fins


Frequently Asked Questions and Their Answers

Principle & Analysis

QWhat are the PBCF advantages?
AAverage 5% FO Saving Effect (at same ship speed) or boost ship's speed by 2% (at same horsepower).
QDoes PBCF an other advantages than energy saving?
A ・Reduction of torque-rich conditions.
・Reduction of stern vibration and underwater noise.
・Elimination of rudder erosion.
QHow is the PBCF effect obtained?
APBCF will eliminate the Hub Vortex.
QDoes PBCF effect change by the size or type of vessel?
APBCF will improve the propeller efficiency and the PBCF effect essentially will not depend on the size or type of the vessel.
QDoes Slow-Steaming influence the PBCF effect?
AYou can expect about 5% effect on average at any ship speed.
QIs there any negative effect for Hull or shafting by installing PBCF?
AThere is no negative effect in any way.
We have installed PBCF over 3,300 vessels until now and there has been no problem for Hull or Shafting.
QIn case of newbuildings, is it necessary to change propeller or shaft design for installation of PBCF?
ANot at all
QIs there any effect for ship-maneuvering performance by PBCF?
AThere is no effect for ship-maneuvering performance (forwarding, reversing, circling, stopping)
QWhy are the values of PBCF effect analysis scattered?
ASea Trial/Voyage Data on actual vessels are included the interference in actual sea way, like wind, wave, sea current and there is a lot of variation in the data.
QMay we ask MOL Techno-Trade to assist in the analysis of the PBCF effect, after installation?
AUpon request, we will analyze PBCF effect and submit a report.

Installation & maintenance

QHow is PBCF installed?
APBCF is fastened to propeller boss by bolts, comparable to the installation of conventional propeller boss cap.
QDoes PBCF price include installation fee?
ANo, installation fee has not included in PBCF price. Installation is the scope of the customer and usually this is included in the customer's Dry-dock planning.
QWhat is the installation time of PBCF?
AIt takes about 5~6 hours by 4 workers.
QDoes your engineer attend during the installation?
AIn case of installation on exising vessels at Chinese dockyard, we offer a service to dispatch our supervisor for installation at our expense.
In case of other area, the additional supervising fee is neccessary.
QWhat is the most important regarding the PBCF installation?
  • 1) Position relation for Propeller Blade and PBCF
  • 2) To use original installation materials, like fastening bolts, torque wrench.
  • 3) Apply correct fastening torque to the bolts. Installation is comparable to the installation of coventional propeller boss cap, without welding works.
QDoes PBCF need specific maintenance?
ANo specific maintenance instructions.
PBCF may follow the propeller maintenance. For example cleaning and polishing. Further we have no objection for special paint or coatings.


QWhat drawings are necessary to design PBCF?
  • 1) Propeller (incl. propeller particular and boss cap)
  • 2) Propeller blade offset table
  • 3) Propeller Shaft (shaft end and propeller nut)
  • 4) Stern arrangement (showing the clearance dimension between propeller and rudder)
  • 5) Rudder
QOf which material is PBCF made?
AIt is Nickel-Almi-Bronze, same as material as propeller.
QCan we switch PBCF between our vessels?
APBCF is custom made product based on propeller design per vessel.
Therefore, PBCF cannot be switched unless completely sister vessel.
QAre PBCF fins removable?
ANo. PBCF is made by using advanced casting technology, as one unit.
QAre there any moving parts on the PBCF?
APBCF has no moving parts.


QWhat is "PBCF"?
AIt is an energy-saving device installed on propeller, improving propeller efficiency.
QWhat does "PBCF" mean?
AIt is named after the initials of "Propeller Boss Cap Fins".
QWho (& When) invented PBCF?
AMitsui O.S.K. Lines, West Japan Fluid Engineering Laboratory Co.,Ltd and Nakashimamitsuwa Propeller Co., Ltd. (ex. Mikado Propeller) has jointly developed PBCF in 1987.
QCan PBCF be installed only to a new-building ship?
ANo, It can easily be installed on both newbuildings and existing vessels.
QDoes PBCF need Class approval?
ANo need. PBCF is not a class approval item same as normal boss cap.
Certain class request to submit PBCF drawing but it will be arranged by MOL Techno-Trade Ltd.
QWhat is the Delivery time of PBCF?
AIt takes usually 3 months from receiving firm order. (Based on Delivery in East Asia) In case of delivery to Middle East, Europe or other area, additional over 1 month will be needed.
QWhich types of vessel can install PBCF?
AAll type of merchant vessels, and also high speed vessels, fishing crafts. PBCF is a propeller improver.
QWhat is included in the PBCF price?
  • 1) PBCF body
  • 2) Accessories set (Original bolts, Calibrated Torque Wrench, Gasket, locking wire and installation manual)
  • 3) For delivery to East Asia by sea freight: transportation included (CIF at port East Asia)
QCan PBCF be installed on a Controllable Pitch Propeller (CPP) ?
AYes, basically possible. However for some propeller maker or type of CPP installation of PBCF is impossible.