What is the extent of thickness measurement at Special Survey No.2 for a bulk carrier?
The second special survey is where the extent table starts asking for steel by name: two transverse sections of deck plating outside the hatch-opening line, the wind-and-water band, and the members the close-up survey covers. Three societies ask for more than that, and the additions are not interchangeable.
The short answer
- Suspect areas, as at every survey.
- Two transverse sections of deck plating, inside the cargo length, outside the hatch-opening line.
- The wind-and-water band at those two sections, plus a selection of the same band beyond the cargo length.
- The close-up members, gauged for general assessment and to record the corrosion pattern.
- Additions: ABS wants the deck between the hatches; DNV pins a section amidships; ClassNK wants the strength deck where corrosive cargoes are carried.
What the UR asks for
Four things sit in the second column of UR Z10.2 Table II, and they are worth reading as four rather than as one paragraph.
First, suspect areas — the standing item that appears in every column of the table. Second, two transverse sections of deck plating, taken inside the cargo length and clear of the line of the cargo hatch openings. Third, the wind-and-water strakes in way of those two sections, together with a selection of the same strakes outside the cargo length area. Fourth, readings over the structural members the close-up survey covers, taken to judge the ship generally and to put its corrosion pattern on record. UR Z10.2 R37
The statutory counterpart carries the same four in the same order. Where the UR binds the society, the ESP Code binds the ship through SOLAS XI-1/2 — on an ESP-notation bulk carrier both apply, and neither is a substitute for the other. A.1049(27)
Note what is not there. No bottom plate. No keel plate. No full-length strake. Those arrive at the third and fourth surveys, and a programme that brings them forward to ten years is spending money the rule does not ask for — unless the ship's own condition has already moved the answer.
The close-up scope, and the deadweight trigger
The fourth item above is the one that produces most of the readings, so the close-up scope decides the size of the job. At the second special survey it is: every shell frame in the forward cargo hold, and 25 % of the frames in each remaining hold, taken with their end attachments top and bottom and the shell plating beside them. UR Z10.2 R37
On a bulk carrier of 100,000 dwt and above that quarter becomes a half in every remaining hold. The trigger is deadweight, not age, and it is the single largest step in the close-up scope anywhere in the chapter — on a capesize it roughly doubles the frame count outside the forward hold. UR Z10.2 R37
The tanks come with it: in every water ballast tank a transverse web with its plating and longitudinals, and in one of those tanks the forward and after transverse bulkheads with their stiffening. Every cargo hold transverse bulkhead, stools included. Every hatch cover and coaming. And the deck plating with the structure beneath it, inside the hatch line between the hold hatches.
Three societies ask for more, and they ask for different things
ABS wants the deck between the hatches. Its column carries the deck plating that lies inside the hatch-opening line, between the cargo hold hatches, on top of the two sections outside that line. No other document in this set asks for it at the second survey. ABS Part 7
DNV pins a section amidships. Where the UR asks for two sections and says nothing about where they fall, DNV requires at least one of the two to be inside 0.5 L amidships. That is a placement condition, not an extra section — but a programme that cuts both sections forward satisfies the UR and fails DNV. DNV Pt.7 Ch.1 Sec.4
ClassNK wants the strength deck where the cargo attacks it. Beside the two sections its column adds all strength deck plating where log cargoes, or other cargoes prone to accelerate corrosion, are loaded. The trigger is the trade the ship is in rather than its age or size, which makes it the one addition in this set that a planner cannot read off the ship's particulars alone. ClassNK Part B
Double-side skin
For a double-side-skin bulk carrier the requirement is UR Z10.5 and, statutorily, part B of annex A of the ESP Code. The systematic column matches the single-skin answer at this survey — two transverse sections of deck plating outside the hatch-opening line, the wind-and-water band in way, and the close-up members. UR Z10.5 R20
The close-up side is where the two ship types part company, and it follows the structure rather than the rule: a double-side-skin hull has no side shell frames in the hold to gauge, and it has double side tanks that a single-skin hull does not. The frame percentages above do not transfer; the transverse web and bulkhead items do.
What moves the answer
The same two conditions that move it at every survey, and one that first bites here.
Substantial corrosion takes the extent out of Table II and into Table VIII — annex 10 in the Code, Table 13 in DNV — and the widened readings are due before the survey is credited.
Coating condition in the ballast tanks puts a tank onto yearly examination, with gauging as the surveyor judges necessary, and keeps it there until the coating is made good.
And the ship crosses ten years here. The intermediate survey that follows this special survey is the first one whose scope is set to the extent of the previous special survey rather than to a lighter list of its own. Whatever this survey establishes is therefore the shape of the next intermediate as well, which is a reason to get the sections placed where they will still be the right sections in two and a half years.
Sources
- UR Z10.2 Rev.37IACS — Hull surveys of bulk carriers, Feb 2023index entry →
- UR Z10.5 Rev.20IACS — Double-skin bulk carriers, Feb 2023official text ↗
- A.1049(27)IMO Res. A.1049(27) — 2011 ESP Codeofficial text ↗
- ABS Part 7ABS — Rules for Survey After Construction, Jul 2026official text ↗
- DNV Pt.7 Ch.1 Sec.4DNV — Rules for Classification: Ships, survey requirements, Jul 2022official text ↗
- ClassNK Part BClassNK — Rules and Guidance for the Survey and Construction of Steel Ships, 2022official text ↗
Class-society and IMO documents are indexed and linked, never re-hosted. Where a class rule is stricter than the IACS baseline, the class rule governs.