W10_DI_STERNTUBE BUSH REPAIR SCHEDULING

1.     Problem recognition, definition and evaluation

In the middle of restoring main engine project MT. Sindang (tanker 40,000 DWT), bushing in sterntube found not appropriate with standard. The Diameter is over size 0.15 – 0.4 mm, white metal contact surface has uneven surface and no vertical offset 0.35mm, & bush inner side fwd and aft side no 30mm slope. 

This condition must be solved as soon as possible before commission test next 4 weeks, otherwise this project will be delayed and everyone will be unhappy.

2.   Development of the feasible alternatives 
      After discussed with contractor and project manager, we have 2 options to solve this problem

             - First option is replace both bushes with the new genuine part from maker.

-                        - Second option is re-machining bushes with support by Class approval.

3.     Development of the outcomes

We will use “Program Evaluation and Review Techique (PERT) application to analyze both choices. This method was first developed by Booz, Allen & Hamilton in 1950 for U.S. Navy programs.  

4.      Selection of the acceptable criteria.

The critical point in this situation is delivery time, because it is related with vessel commission test.

The option that will we choose is the fastest time to fix sterntube bushes.

 

5.      Analysis and comparison of the alternatives

Detail data (base on quotation from third parties, owner estimate & expertise experiences) will calculate and simulate using WinQSB 1.0 version program.

First Option: Replace both bushes with the new genuine part from maker

 Table 1. Activities for option 1

 

Table 2. Detail activities & Estimate time option 1

Table 3. Activities Analyze option 1

table 4. Gantt Chart & Probabilistic Activity Time option 1

table 5. Probability analyze option 1

Second option: Re-machining bushes with support by Class approval

 Table 6. Activities for option 2

  

 

Table 7.  Detail activities & Estimate time option2

Table 8. Activities Analyze option 2

 

Table 9. Gantt Chart & Probabilistic Activity Time option 2

Table 10. Probability analyze option2

6.     Selection of the preferred alternative

Re-machining is the best choice we have which is faster than renew with 28 day instead of 32 days with 50% probability.

7.     Performance Monitoring & Post Evaluation of Result 

      There are 4 important things must be understood by a Project Manager as shown in picture below:

Project manager must make a choice base on situational condition, sometime they increase the budget to speed up the progress, sometime they reduce scope of work to speed up the progress and saving money, and sometime they increase the budget and time to get better quality.

This sterntube case actually is in the middle of huge project, so our main consideration is about delivery time and cost instead of quality.

Reference: 

         i.   Taylor D. A.  Introduction to Marine Engineering Second Edition,   (Elsevier Butterworth-Heinemann, 1996) Chapter 11 Shafting & propellers, pp. 200-211

       ii.   4 hal Penting dalam Project anagement, retrieved from: 

http://hech61.wordpress.com/2008/11/26/4-hal-penting-dalam-project-management/

      iii.   Booz Allen Hamilton – Historical Timeline, retrieved from:

http://www.boozallen.com/media/file/150598.pdf