15. SUMMARY

We could go on and on. The down ratchet works everywhere. Rudder stock dimensions, steering gear torque, propeller blades, awkward and dangerous outfitting including pump room ventilation ducts that don't go to the pump room bottom, etc, etc. Table 15.1 shows one last example: main engine shaft couplings.
TABLE 15.1
Deterioration in Main Shaft Couplings, 1975 to 2001
19752000
Power45,000 SHP44,640 BHP
RPM8576
Engine Torque Pulsenil80%
Flange Thickness220 mm140 mm
Coupling Bolts14 x 150 mm conical12 x 95 mm reamer
We are not talking about losing 15 to 20% here. We are talking about losing 150 to 200% despite the much harsher design conditions associated with the diesel and its massive torque fluctuations. We know of three shaft coupling failures in new VLCC's, which means we can be sure there have been more. The repair yards tell us there is no chance of unscrewing the shaft couplings when the new V's come in for their first docking. They expect to have to drill them out since they all been over-torqued and badly fretted. And what does the owner gain for taking these massive risks? A few thousand dollars per ship which he will give back to the repair yard on the first docking. This is the down ratchet gone berserk.

Table 15.1 is an extreme case, but it is very difficult to find any scantling or parameter that is not at least 15% weaker on the new ships than the old. As a result, large tankers built to current Class rules are far less safe and less reliable vessels than those built 25 years ago. And the mid-70's ships as a group were not over-built. They were at best just good enough. Yet in the same period the potential liabilities associated with large tanker casualties have increased one hundred fold. It simply makes no sense. If the classification society system is to continue to exist, if it should be allowed to continue to exist, the Rules must be rewritten returning at a minimum to the standards of the 1970's. And the direct computation down ratchet must be eliminated.

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