RESISTANCE OF SHIP

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          Resistance of ship is the opposing force experienced by the body while moving through liquid.

Types of Resistance:-
1. Wave making resistance
2. Frictional resistance
3. Viscous pressure drag
4. Eddy making resistance
5. Appendage resistance
6. Wind making resistance

Methods to find resistance:-
l) From model test 
    - done in towing tanks
    - models attached to the carriage
    - platform has a dynamometer from which resistance is measured
    - resistance tests are done in smooth water


2) From methodical series
       - test starts with a parent form
       - a number of significant form parameters are varied
       - results show how resistance varies with form parameters
       - useful for estimating power for new designs


Different methodical series
     - Taylor series
     - BSRA series
     - Gulhammer & Harward series
     - DTMB series


Using Gulhammer & Harward series

Step 1:-

   Residual resistance coefficient and frictional resistance coefficient are found out using series diagrams

Step 2:-

   Rf= Cf*rSV2

   Rr= Cr*rSV2

Step 3:-

     Total resistance=Residual resistance + Frictional resistance

Step 4:-

     Plot resistance curves vs velocity

  Effective Power = TOTAL RESISTANCE X VELOCITY OF SHIP 

Resistance Curves:-


         To Conclude, Engine must be designed such that it must be able to overcome the Resistance


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