Webinar recording March 2021

The recording of this webinar will take you through the proposed changes, what triggered the changes to the standard and how you can provide your feedback.

Moderator: Craig Elliot, Senior Advisor, Vessel Standards, AMSA

The proposed changes to the requirements for watertight and weathertight integrity take into account developments in technology and better align the requirements with international standards and best practice.

View our webinar from 9 March 2021

Questions and answers

Read the compilation of questions and answers from the two webinars conducted 1st March and 9th March 2021.

Question numberIndustry or accredited marine surveyor questionsAnswers from AMSA
1Very often hatch covers are tested for water tightness while a vessel is at berth before loading operations, and on the same vessel I experience water ingress during the sea passage, which obviously occurs due to racking forces and shipping seas. Are the coming changes for design of hatch covers?This is outside of the scope of the NSCV C2 standard. What you are referring to are the construction hull standards and global hull strength. Domestic commercial vessels of 35m or more in measured length must be constructed to the structural rules of a recognised organisation.
2Has there been any interest in using drones within the hold to video leaks while Hose testing is being carried out? Lighting on drone would be a must.Remote survey and the use of drones is not part of the scope of this standard and has not been considered as part of this review.
3What’s the definition of watertight and weather tight and what is the difference?

Both watertight and weathertight are defined with the NSCV C2 Consultation draft at clause 1.4 Definitions.

Watertight means having scantling and arrangements capable of preventing the passage of water in any direction under the head of water likely to occur in intact and damaged conditions. In the damaged condition, the head of water is to be considered in the worst situation at equilibrium, including intermediate stages of flooding.

Weathertight means that in any sea conditions, water will not penetrate into the vessel.

This means in practice; Weathertight closing appliances are primarily located above the waterline of the vessel. They are designed to prevent the ingress of water from outside to inside. This generally includes a small head of water. Their main purpose is to prevent the ingress of green seas into the space of the vessel they are designed to protect.

On the other hand, Watertight closing appliances are designed to prevent water ingress from both sides and can withstand a significant water column (pressure), thereby ensuring that the watertight integrity of the neighbouring compartment of the vessel is not lost. Generally, they are located below deck level.

4I have an ultrasonic testing machine and it is certified by ABS and RINA. Do I have to have any sort of certification to use this equipment? This is very simple equipment though very effective.Training requirements are not part of the standard.

Are there provisions now, or especially in the future, for providing standards for watertight integrity or design to mitigate water ingress for batteries, battery housing, or battery envelopes? I would like to provide a drawing if asked.


This is outside of the scope of the NSCV C2 standard. However, NSCV C5B Electrical does describe protection requirements from exposure to moisture for electrical equipment and batteries. NSCV C5A Machinery also specifies requirements for bilge battery locations to ensure adequate protection.

Also, AMSA will soon make additional guidelines available for the design and installation of:

  1. Lithium-ion Electrical Energy Storage Systems
  2. Electrical Propulsion Systems
6Converting a vessel from 3C to 2C —– are there any issues with ‘watertight & weathertight integrity’ issues? I am looking at buying a 3C vessel and changing the survey from 3C to 2C.The proposed NSCV C2 standard, generally, will not impact existing vessels. However, vessels changing service category and operations may need to comply with transitional requirements, and need to be re-assessed against MO503. If this is the case the new requirements of C2 may apply to your vessel.
7Will AMSA provide stability (maximum loading) placards?AMSA does not intend to provide stability placards. AMSA will however, provide additional guidance around the format of the stability placard based on the requirements of NSCV C6C Annex J.
8In my view, the term ‘weathertight’ should apply only to land based structures. Why make this loophole to commercial boats operating at sea? (Even large ships will be subjected to the full force of nature, and should be ‘watertight’ even above deck)Weathertight closing devices are defined within many IMO International conventions, like SOLAS for example. NSCV C2 incorporates many of the elements and requirements from the International convention of load lines, of which external weathertight and watertight integrity are both objectives of the convention. Please see question 3 above for the definition and further information regarding weathertight integrity.
9Is there any change to the deemed acceptable number of Watertight hinged doors for charter vessels up to 24m?

Can a weathertight door in the side of a superstructure be regarded as watertight for large angle stability modelling?

Will a direct escape to the open deck from an engine room have an option for the escape via an adjacent Watertight compartment?
  1. No, this is outside the scope of the NSCV C2 standard. Any changes to the number of WT hinged doors for vessels under 24m would be dealt with by NSCV C6B Buoyancy and stability after flooding, which will commence being reviewed later this year.
  2. This is outside of the scope of the NSCV C2 standard. NSCV C6A defines the downflooding angle within clause 1.7 definitions.
  3. Questions about escape routes are outside of the scope of NSCV C2 standard. NSCV C1 contains escape requirements and is currently under review.
10(1) Ref. Section 4.6(4) and the requirement for sliding weathertight doors in aft superstructure of Class 3 vessels > 12m.
(a) Why does this not apply to other vessel type which, it could be argued, are at equal risk of capsize (i.e. tugs towing)?
(b) Why should this apply to a fishing vessel which does not tow nets, i.e. a longline fishing vessel and not to a Class 2 vessel?
(b) Procurement of sliding weathertight doors in accordance with the nominated standards is difficult.
(2) Ref Sections 4.12 (1) and 4.13 (1)
(a) the nominated standards do not include Class accepted international standard bottom plugs, windows or portlights which may be installed in larger vessels (i.e. ISO 1751, ISO 3903 or ISO 5483).
(3) Ref Section 4.18(1)
(a) Why the need to add together freeing port and scupper areas?
  1. This was only a proposal within the NSCV C2 consultation draft and after further consideration, AMSA has determined that these kinds of measures are escape type measures, which best reside within NSCV C1. NSCV C1 is currently under review also.
  2. ISO 1751 and ISO 3903 are nominated standards within chapter 3 as the scope of these standards is for vessels greater than 24m in length. ISO 5483—Ships and marine technology —Drain facilities from oil and water tanks, will be considered by the project team for inclusion into the NSCV C2 standard.
  3. Please see the recorded NSCV C2 webinar for a detailed explanation and a worked example. AMSA will also make a small change to the standard and write ’if scuppers are required‘, into the provision to help clarify the requirements.
11Will this new chapter provide Deemed to satisfy solutions for various measured length limits used in Pt C3, 6A and 6B? i.e. 7.5 m, 12.5 m, 13 m, 16 m, 35 m, 80 m, 100 m etc. If all these measured lengths can be standardised throughout, it will be easy to work out a solution.

AMSA is trying to simplify and cater for a wide range of vessels. The predominate lengths for consideration in NSCV standards for surveyed vessels are:

  1. <7.5m
  2. ≥7.5m to <12m
  3. ≥12m to <24m
  4. ≥24m to <35m (Optional for some standards).
  5. ≥35m+
  1. Tables 2 – 5 require sills on hatches in Position 1. In the case of an access hatch to a forepeak void (Other Hatches) this hatch would not likely be opened at sea, and the requirement for a sill could pose a trip hazard on a vessel with foredeck access, i.e. passenger vessel or workboat. Could sill requirement include consideration of the space being accessed by the hatch?
  2. 4.10 Air Pipes (1) inclusion of ‘voids, cofferdams and duct spaces’ may be confused as spaces that would have required ventilators under USL, as a void may be a large compartment directly below the freeboard deck. USL 5C C71 defined air pipes for tanks, so it was assumed anything not a tank required a ventilator. Can this definition please be clarified?
  3. Is there consideration to not having closing devices fitted to air pipes as for Ventilators Clause 4.8 (2)?
  1. AMSA agrees, and yes consideration has been given in the standard. Both ‘No direct access leading below the weather deck column’ and the ‘Normally closed at sea (regardless of position)’, means a hatch in position 1 can be flush if it’s normally closed at sea. AMSA will add both these terms to the definitions at clause 1.4 of the NSCV C2 standard.
  2. The clause at 4.10 (1) is trying to prevent excessive pressure on tank boundaries and to ensure provisions are made for relieving vacuum when tanks are being drawn from or emptied. AMSA will consider rewording slightly.
  3. AMSA will further consider the risk posed by small diameter air pipes and ventilators.
13Will AMSA concede that these changes could be at great expense to owners of grandfathered vessels if they are to be brought up to the new standard? Safety is extremely important, however with lots of smaller operators living off pay check to pay check, its just another bill they have to find money for.

A vessel that, for example, has worked the same waterway for 40 years, with a flawless safety record now all of a sudden now needs new sea doors and deck hatches?

Shouldn't AMSA be proactive and be giving out grants to owners for vessels that have to be modified that would be the right thing to do?
  1. The proposed new NSCV C2 standard will not apply to the vast majority of existing vessels. The proposed standard is scheduled to become mandatory in late 2022 for vessels entering commercial service for the first time.
  2. If a vessel has held a certificate of survey for 40 years and continues to pass periodic surveys and safety inspections, the proposed NSCV C2 standard will not apply to such a vessel.
  3. The proposed NSCV C2 standard is not seeking to modify existing vessels. It is setting slightly revised build standards for new vessels being generally built from late 2022 onwards.