Skip to main content

Propeller slip

  • When the vessel is moving ahead the propeller exerts pressure on the water to create the forward motion. 
  • Propeller slip occurs because water is not a solid medium and there is some slip related to it.
  • Slip may be considered as the difference between the speed of the vessel and the speed of the engine. 
  • It is always expressed as a percentage.
Propeller Slip = Actual forward speed/ Theoretical forward speed.
  • The calculated value of slip will be increased when the wind and sea are ahead and if the vessel has a fouled bottom. 
  • The differing values of slip are especially noticeable after a vessel has been cleaned in drydock.
  • Theoretically a vessel should never have negative slip, but this may occur in one or more of the following conditions:--  A strong following sea.
                                                                         A following current or a strong following wind

How to find the Propeller Slip
Mean Apparent slip = Distance run by propeller - distance run by ship per day
                                                             Distance run by propeller

Distance run by propeller in nautical miles = Pitch(m) x total engine revolution per day
                                                                                       1852
Labels:

Comments

  1. Ferlin MotorAugust 10, 2021 at 10:06 PM

    Hey what a brilliant post I have come across and believe me I have been searching out for this similar kind of post for past a week and hardly came across this. Thank you very much and will look for more postings from you Best Used Outboard Motors for sale Craigslist service provider.

    ReplyDelete
  2. AL SOL MARINE SERVICESDecember 5, 2021 at 8:26 PM

    You have shared a lot of information in this article. I would like to express my gratitude to everyone who contributed to this useful article. Keep posting. marine suppliers

    ReplyDelete
  3. Rajasthan Tourism TravelsJuly 5, 2022 at 5:35 AM

    Desert Safari Camp In Jaisalmer Lovely blog...! It is one of the best posts for this topic and I really appreciate your great efforts.

    ReplyDelete
  4. Rajasthan Tourism TravelsJuly 5, 2022 at 5:35 AM

    Thanks for sharing this article we provide Best Wooden Handicraft Furniture In Jodhpur service all over India please contact us. Handicrafts From India

    ReplyDelete
  5. AnonymousNovember 10, 2024 at 7:32 AM

    By the slip defined above, is the real slip, apparent slip or effective slip?

    ReplyDelete

Post a Comment

If you have any doubts.Please let me know

Popular posts from this blog

Differences between MC/MC-C and ME/ME-C engines

The electrohydraulic control mechanisms of the ME engine replace the following components of the conventional MC engine: Chain drive for camshaft Camshaft with fuel cams, exhaust cams and indicator cams Fuel pump actuating gear, including roller guides and reversing mechanism Conventional fuel pressure booster and VIT system Exhaust valve actuating gear and roller guides Engine driven starting air distributor Electronic governor with actuator Regulating shaft Engine side control console Mechanical cylinder lubricators. The Engine Control System of the ME engine comprises: Control units Hydraulic power supply unit Hydraulic cylinder units, including: Electronically controlled fuel injection, and Electronically controlled exhaust valve activation Electronically controlled starting air valves Electronically controlled auxiliary blowers Integrated electronic governor functions Tacho system Electronically controlled Alpha lubricators
9 comments
Read more

Main engine interlocks

Interlocks are provided so that the engine can be started or reversed only when certain conditions have been fulfilled. When there is a remote control of engines, it is essential to have interlocks. This reduces the possibility of engine damage and any hazards to the operating personnel. Turning gear Interlock . This device prevents the engine from being started if the Turning gear is engaged. Running Direction Interlock . This prevents the fuel from being supplied if the running direction of the engine does not match the Telegraph. Starting Air Distributor in end position . This prevents starting from taking place if the shifting of the Distributor has not been completed. Main Lube. oil pressure, Piston cooling pressure, Jacket water pressure, and important parameters must be above the required minimum. Auxiliary Blower Interlock . The Auxiliary Blower is provided in case of Constant pressure turbo charging. Air Spring pressure Interlock . In case of the present generation
7 comments
Read more

Why is a man hole door elliptical in shape?

Any opening in a pressure vessel is kept to a minimum and for a man entry an elliptical hole  is lesser in size than the corresponding circular hole. More over it is prime concern to have a  smoothed generous radius at the corners to eliminate stress concentration. Hence other  geometrical shapes like rectangle and square are ruled out.  To compensate for the loss of material in the shell due to opening, a doubler ring has to be  provided around the opening. The thickness of the ring depends on the axis length along the  dirrection in which the stresses are maximum and the thickness of the shell. It is important to  align the minor axis along the length of the vessel, as the stress in this direction is  maximum. Longitudinal stress: Pd/2t where P= pressure inside the vessel, d= diameter of the arc, t=  thickness of the shell plating  Circumferential stress: Pd/4t  More over a considerable material and weight saving is achieved as minor is along the  direction of maximum stress.
20 comments
Read more