New common IACS Rules for Tankers IACS Joint Tanker Rules Presentation/discussion with Intertanko Spetses September 2004

New common IACS Rules for Tankers Items presented  Status of the JTP Rules  Schedule  Hearing  Harmonisation in IACS  Ongoing work  Concerns and recommendations from Intertanko  Consequences of the JTP Rules  Calibration of the Rules  Consequence in general terms  Consequence in numbers  Open discussion

New common IACS Rules for Tankers Status of Joint Tanker Rules - Schedule Draft Rules IACS Adoption IACS External Review (Industry involvement) Publication Internal Review Key dates  30th September 04: Closing date for hearing comments  20th October 04: Project reply to TC comments.  1st January 05:Publish Joint Tanker Rules  1st July 05:Rules come into force

New common IACS Rules for Tankers Status of Joint Tanker Rules Hearing  1800 questions/comments received  questions expected  Replies available by 20 October 04  FAQ list will be posted on the website  Main concern so far is timing Harmonisation  Harmonisation of JTP and JBP has been initiated  Differences and needs for adjustments are being worked out in the small technical groups  Way forward with corresponding schedule is being discussed in IACS council.

New common IACS Rules for Tankers Status of Joint Tanker Rules Ongoing work  Review of comments  Extended consequence evaluation  Rule review with respect to possible loopholes  Software comparison  Improvements/adjustments  Inclusion of Rule required seagoing and harbour still water bending moments.  Refinement of internal tank pressures  Refinement of load combinations in terms of static and dynamic loads

New common IACS Rules for Tankers Concerns and recommendations from Intertanko Concern 3-1 More extensive comparative/ramification calculations should be presented. Unfortunately, the comparative calculations presented into the JTP web site are not conclusive, providing only the increment of the scantlings in some areas but not defining into detail the base line design used. Is the increment in scantlings as compared to the highest value of the three societies’ existing rules? Is it related to an average value between the three societies’ current rules values or is it related to the minimum of the three societies current values? The comparative studies should be transparent and include not only mid-ship sections but also the forward and aft bodies.

New common IACS Rules for Tankers Concerns and recommendations from Intertanko Concern 3-2 We believe the corrosion margins proposed in the JTP rules are lower than under the current designs on similar ships. It appears that the proposed common rules have increased t net to meet the buckling criteria but the t grs was not increased accordingly. This results in lower t corr values than on the current designs. Tanker owners and actually the receivers of such a vessel believe this is (1) not in the spirit of the concept of a robust ship and (2) would result in more frequent repairs and steel renewals and therefore not acceptable. It is demonstrated that for long hauls, double hull tankers receiving cargo at high temperature, would act as a thermos. The corrosion margins for the cargo tanks and their adjacent ballast tanks of such ships (i.e. tankers loading in tropical areas) should be higher. The corrosion allowances should be even higher for cargo tanks with means for cargo heating. Similar for ballast tanks adjacent to cargo tanks transported heated cargo. we do not believe that the database on wastage used is relevant if it could give such a result. (6/Table 6.3.3)

New common IACS Rules for Tankers Concerns and recommendations from Intertanko Concern 3-3 Particular concern is with regard to the constant value of 0.5 mm for tcorr(2.5) It has been assumed that 0,5 mm is a sufficient safety margin for a period of 2 ½ years. This assumption is unrealistic and dangerous. There is sufficient experience and Classification Societies should know best that a number of ship, particular crude carriers but also other type of tankers have experienced “super corrosion” rates in their cargo tanks, as high as 1 or 2 mm per year. As long as cargo tanks (particularly under deck and bottom structures) are not protected against corrosion and as long as negative tolerance of thicknesses of these structural elements is accepted, a safety margin somewhere between 0.5 mm and 0.2 mm is totally insufficient for a few months not for 2 ½ years. Concluding, the corrosion margins, as presented do not seem to give a safety cushion to keep the ships robust not only as new built but also when in service.

New common IACS Rules for Tankers Concerns and recommendations from Intertanko Concern 3-4 The net scantling concept originally meant "gross thickness minus corrosion addition" but is now changed to reflect "gross thickness minus ½ corrosion addition". This is considered a major philosophical change that needs clarification (6/ ).

New common IACS Rules for Tankers Concerns and recommendations from Intertanko Concern 3-5 t corr for bunker tanks with heated bunkers need to be higher than proposed (6/Table 3.3.2)

New common IACS Rules for Tankers Concerns and recommendations from Intertanko Concern 3-6 Tankers should not be designed with operational restrictions. to the contrary, tankers should be designed to handle all the operating conditions that it could reasonably be expected to face in normal commercial practice with a healthy margin for operator error. (7/6) The common rules should allow: (1) any transverse combination of cargo tanks across to be empty at or near design draft, (2) a reasonable range of asymmetric cargo loads at full draft, (3) all ballast tanks to be 100% full for a full range of bunkers, (4) the ship to ballast down to a reasonably deep draft without resorting to ballasting cargo tanks (5) any single ballast tank to be empty with all the other ballast tanks full, (6) normal ballast exchange (not only flow through) sequence without restriction on weather.

New common IACS Rules for Tankers Concerns and recommendations from Intertanko Concern 3-7 Use a ballast and cargo specific gravity of tonn/m 3 for the fatigue assessment; this will give flexibility in trading (2/ & 7/ & 7/ )

New common IACS Rules for Tankers Concerns and recommendations from Intertanko Concern 3-8 The hull girder buckling strength to be extended to the entire hull. (8/1.6.1)

New common IACS Rules for Tankers Concerns and recommendations from Intertanko Concern 3-9 The FE analysis should cover the entire length of the ship (9/ )

New common IACS Rules for Tankers Concerns and recommendations from Intertanko Concern 3-10 Permissible deflections – if deflection criteria are exceeded, then a detail fatigue analysis is required ( )

New common IACS Rules for Tankers Concerns and recommendations from Intertanko Concern 3-11 The rules apply exclusively to L>150m, whereas the existing unified requirements apply to L>90m. Oil tankers 90>L<150m should be considered

New common IACS Rules for Tankers Concerns and recommendations from Intertanko Concern 3-12 The calculated probability level of 10-8 for a 20-year design life has not been adjusted to 25 years. Why?

New common IACS Rules for Tankers Concerns and recommendations from Intertanko Recommendation 2-1 Inclusion of a prescribed mandatory coating life, e.g. minimum of 15 years. This is to support the assumption made by the rules that the coating will remain undamaged for the first 20 years of the ship’s life (see C/ ).

New common IACS Rules for Tankers Concerns and recommendations from Intertanko Recommendation 2-2 Inclusion of a performance standard for coating application and coating maintenance.

New common IACS Rules for Tankers Concerns and recommendations from Intertanko Recommendation 2-3 Inclusion of the IACS Recommendation 47, Part A - Shipbuilding and Repair Quality Standard for New Construction and not a National standard. As a result, the JTP team should remove from the proposed common rules the alternative of “surveyor discretion” with regard to constructions standards. The IACS Standards should be applicable.

New common IACS Rules for Tankers Concerns and recommendations from Intertanko Recommendation 2-4 Include new provisions to ensure the structural continuity, particularly the inner bottom and double side stringers into the fore body and aft body.

New common IACS Rules for Tankers Concerns and recommendations from Intertanko Recommendation 2-5 Include new provisions to address the hull flexing/deflection problems. There is no rule that would limit hull optimisation which may lead to increases in frame and web spacing and which lead to a decrease of the stiffness of the hull girder. Deflection of the aft body is critical to the shaft alignment.

New common IACS Rules for Tankers Concerns and recommendations from Intertanko Recommendation 2-6 Include provisions to cover the Ice-Classed tankers. There are significant differences between the current regulations of various Classification Societies in this regard. Although this might not be the first priority for the JTP team before implementing the new common rules, we would urge them to add provisions for ice-classed tankers into the common rules as soon as practical possible.

New common IACS Rules for Tankers Consequences of the JTP Rules Rule changes and consequences in general terms Minimum thicknesses - Minimum thicknesses included similarly as today  Baseline is at least as high as existing ships Longitudinal strength - IACS URS fully implemented - Increased hull girder wave shear - New advanced buckling check and hull girder ULS  Deck is strengthened compared to existing ships  Longitudinal bulkheads are strengthened towards tbhds

New common IACS Rules for Tankers Consequences of the JTP Rules Rule changes and consequences in general terms Prescriptive rules - Increased load level - Simultaneously acting loads - Slamming/sloshing bow impact based on most onerous of the existing three Rule sets - Increased corrosion additions  Similar or higher scantlings compared to existing ships  Slightly higher increase in the midship compared with fwd/aft cargo area.

New common IACS Rules for Tankers Consequences of the JTP Rules Rule changes and consequences in general terms FEM - Increased load level - Simultaneously acting loads - Increased corrosion additions - New method for buckling assessment  Increases due to buckling and hull girder shear  Main increase in bottom plating, side shell plating, hopper tank top, transverse bulkhead plating, web frames and stringers

New common IACS Rules for Tankers Consequences of the JTP Rules Rule changes and consequences in general terms Fatigue - North Atlantic wave environment - 25 year design life - Preliminary check included in longitudinal strength  Significantly higher baseline standard compared to today  Main increase in bottom longitudinals in the midship, and side longitudinals in the cargo area.  Difficult with high tensile 36 grade in deck  Will for some vessels dictate the hull girder section modulus

New common IACS Rules for Tankers Consequences of the JTP Rules Consequence in numbers – VLCC midship Ref. As. Bu. [mm]  [mm] As.Bu. ProfileChange % x x x x x x15 +50% x x20 +10% x12+200x20+10% x12+200x20+40% x12+200x20+20% x12+200x20+2% x12+180x20-6% x12+130x20+50% x12+200x20+2% x12+180x20-8% x12+150x15+50%

New common IACS Rules for Tankers Consequences of the JTP Rules Consequence in numbers – VLCC midship Ref. As. Bu. [mm]  [mm] As.Bu. ProfileChange % x x26-23% x x26-8% x x15-3% NA NA NA NA NA NA NA NA NA

New common IACS Rules for Tankers Consequences of the JTP Rules Consequence in numbers – Aframax midship Ref. As. Bu. [mm]  [mm] As.Bu. ProfileChange % X90X11/16+10% X90X11/16+10% X90X12/16 +25% X100X13/18 +20% X X14 +30% X X14 +35% X X14 +25% X X14 +30% X100X12/ X90X11/16 +30% X100X12/17+20% X90X13/ X90X11/

New common IACS Rules for Tankers Consequences of the JTP Rules Consequence in numbers – Aframax midship Ref. As. Bu. [mm]  [mm] As.Bu. ProfileChange % X X X X X X NA 18 0 NA NA NA NA NA NA NA NA