For the purposes of the present Treaty, the following expressions are to be understood in the sense hereafter defined.

A. Standard Displacement

1. The standard displacement of a surface vessel is the displacement of the vessel, complete, fully manned, engined, and equipped ready for sea, including all armament and ammunition, equipment, outfit, provisions and fresh water for crew, miscellaneous stores and implements of every description that are intended to be carried in war, but without fuel or reserve feed water on board.

2. The standard displacement of a submarine is the surface displacement of the vessel complete (exclusive of the water in non-watertight structure), full manned, engined and equipped ready for sea, including all armament and ammunition, equipment, outfit, provisions for crew, miscellaneous stores and implements of every description that are intended to be carried in war, but without fuel, lubricating oil, fresh water or ballast water of any kind on board.

3. The word "ton" except in the expression "metric tons" denotes the ton of 2,240 lb. (1,016 kilos).

B. Categories

1. Capital ships are surface vessels of war belonging to one of the two following sub-categories:

   1. Surface vessels of war, other than aircraft-carriers, auxiliary vessels, or capital ships of sub-category (b), the standard displacement of which exceeds 10,000 tons (10,160 metric tons) or which carry a gun with a calibre exceeding 8 in. (203 mm.);

   2. Surface vessels of war, other than aircraft-carriers, the standard displacement of which does not exceed 8,000 tons (8,128 metric tons) and which carry a gun with a calibre exceeding 8 in. (203 mm.).

2. Aircraft-carriers are surface vessels of war, whatever their displacement, designed or adapted primarily for the purpose of carrying and operating aircraft at sea. The fitting of a landing-on or flying-off deck on any vessel of war, provided such vessel has not been designed or adapted primarily for the purpose of carrying and operating aircraft at sea, shall not cause any vessel so fitted to be classified in the category of aircraft-carriers.

   The category of aircraft-carriers is divided into two sub-categories as follows:

   1. Vessels fitted with a flight deck, from which aircraft can take off, or on which aircraft can land from the air;

   2. Vessels not fitted with a flight deck as described in (a) above.

3. Light surface vessels are surface vessels of war other than aircraft-carriers, minor war vessels or auxiliary vessels, the standard displacement of which exceeds 100 tons (102 metric tons) and does not exceed 10,000 tons (10,160 metric tons), and which do not carry a gun with a calibre exceeding 8 in. (203 mm.).

   The category of light surface vessels is divided into three sub-categories as follows:

   1. Vessels which carry a gun with a calibre exceeding 6.1 in. (155 mm.);

   2. Vessels which do not carry a gun with a calibre exceeding 6.1 in. (155 mm.) and the standard displacement of which exceeds 3,000 tons (3,048 metric tons);

   3. Vessels which do not carry a gun with a calibre exceeding 6.1 in. (155 mm.) and the standard displacement of which does not exceed 3,000 tons (3,048 metric tons).

4. Submarines are all vessels designed to operate below the surface of the sea.

5. Minor war vessels are surface vessels of war, other than auxiliary vessels, the standard displacement of which exceeds 100 tons (102 metric tons) and does not exceed 2,000 tons (2,032 metric tons), provided they have none of the following characteristics:

   1. Mount a gun with a calibre exceeding 6.1 in. (155 mm.);

   2. Are designed or fitted to launch torpedoes;

   3. Are designed for a speed greater than twenty knots.

6. Auxiliary vessels are naval surface vessels the standard displacement of which exceeds 100 tons (102 metric tons), which are normally employed on fleet duties or as troop transports, or in some other way than as fighting ships, and which are not specifically built as fighting ships, provided they have none of the following characteristics:

   1. Mount a gun with a calibre exceeding 6.1 in. (155 mm.);

   2. Mount more than eight guns with a calibre exceeding 3 in. (76 mm.);

   3. Are designed or fitted to launch torpedoes;

   4. Are designed for protection by armour plate;

   5. Are designed for a speed greater than twenty-eight knots;

   6. Are designed or adapted primarily for operating aircraft at sea;

   7. Mount more than two aircraft-launching apparatus.

7. Small craft are naval surface vessels the standard displacement of which does not exceed 100 tons (102 metric tons).

C. Over Age

Vessels of the following categories and sub-categories shall be deemed to be "over-age" when the undermentioned number of years have elapsed since completion:

1. Capital ships 26 years

2. Aircraft carriers 20 years

3. Light surface vessels, sub-categories (a) and (b):

   1. If laid down before 1 January 1920 16 years

   2. If laid down after 31 December 1919 20 years

4. Light surface vessels, sub-category (c) 16 years

5. Submarines 13 years

D. Month

The word " month" in the present Treaty with reference to a period of time denotes the month of thirty days.

After the date of the coming into force of the present Treaty, no vessel exceeding the limitations as to displacement or armament prescribed by this Part of the present Treaty shall be acquired by any High Contracting Party or constructed by, for or within the jurisdiction of any High Contracting Party.

No vessel which at the date of the coming into force of the present Treaty carries guns with a calibre exceeding the limits prescribed by this Part of the present Treaty shall, if reconstructed or modernised, be rearmed with guns of a greater calibre than those previously carried by her.

1. No capital ship shall exceed 35,000 tons (35,560 metric tons) standard displacement.

2. No capital ship shall carry a gun with a calibre exceeding 14 in. (356 mm.); provided however that if any of the Parties to the Treaty for the Limitation of Naval Armament signed at Washington on 6 February 1922, should fail to enter into an agreement to conform to this provision prior to the date of the coming into force of the present Treaty, but in any case not later than 1 April 1937, the maximum calibre of gun carried by capital ships shall be 16 in. (406 mm.).

3. No capital ship of sub-category (a), the standard displacement of which is less than 17,500 tons (17,780 metric tons), shall be laid down or acquired prior to 1 January 1943.

4. No capital ship, the main armament of which consists of guns of less than 10 in. (254 mm.) calibre, shall be laid down or acquired prior to 1 January 1943.

1. No aircraft-carrier shall exceed 23,000 tons (23,368 metric tons) standard displacement or carry a gun with a calibre exceeding 6.1 in. (155 mm.).

2. If the armament of any aircraft-carrier includes guns exceeding 5.25 in. (134 mm.) in calibre, the total number of guns carried which exceed that calibre shall not be more than ten.

1. No light surface vessel of sub-category (b) exceeding 8,000 tons (8,128 metric tons) standard displacement, and no light surface vessel of sub-category (a) shall be laid down or acquired prior to 1 January 1943.

2. Notwithstanding the provisions of paragraph (1) above, if the requirements of the national security of any High Contracting Party are, in his opinion, materially affected by the actual or authorised amount of construction by any Power of light surface vessels of sub-category (b), or of light surface vessels not conforming to the restrictions of paragraph (1) above, such High Contracting Party shall, upon notifying the other High Contracting Parties of his intentions and the reasons therefor, have the right to lay down or acquire light surface vessels of sub-categories (a) and (b) of any standard displacement up to 10,000 tons (10,160 metric tons) subject to the observance of the provisions of Part III of the present Treaty. Each of the other High Contracting Parties shall thereupon be entitled to exercise the same right.

3. It is understood that the provisions of paragraph (1) above constitute no undertaking expressed or implied to continue the restrictions therein prescribed after the year 1942.

No submarine shall exceed 2,000 tons (2,032 metric tons) standard displacement or carry a gun exceeding 5.1 in. (130 mm.) in calibre.

Every vessel shall be rated at its standard displacement, as defined in Article 1A of the present Treaty.

No preparations shall be made in merchant ships in time of peace for the installation of warlike armaments for the purpose of converting such ships into vessels of war, other than the necessary stiffening of decks for the mounting of guns not exceeding 6.1 in. (155 mm.) in calibre.

Vessels which were laid down before the date of the coming into force of the present Treaty, the standard displacement or armament of which exceeds the limitations or restrictions prescribed in this Part of the present Treaty for their category or sub-category, or vessels which before that date were converted to target use exclusively or retained exclusively for experimental or training purposes under the provisions of previous treaties, shall retain the category or designation which applied to them before the said date.

1. Each of the High Contracting Parties shall communicate every year to each of the other High Contracting Parties information, as hereinafter provided, regarding his annual programme for the construction and acquisition of all vessels of the categories and sub-categories mentioned in Article 12(a), whether or not the vessels concerned are constructed within his own jurisdiction, and periodical information giving details of such vessels and of any alterations to vessels of the said categories or sub-categories already completed.

2. For the purposes of this and the succeeding Parts of the present Treaty, information shall be deemed to have reached a High Contracting Party on the date upon which such information is communicated to his diplomatic representatives accredited to the High Contracting Party by whom the information is given.

3. This information shall be treated as confidential until published by the High Contracting Party supplying it.

The information to be furnished under the preceding Article in respect of vessels constructed by or for a High Contracting Party shall be given as follows; and so as to reach all the other High Contracting Parties within the periods or at the times mentioned:

1. Within the first four months of each calendar year, the Annual Programme of construction of all vessels of the following categories and sub-categories, stating the number of vessels of each category or sub-category and, for each vessel, the calibre of the largest gun. The categories and sub-categories in question are:

   • Capital ships:
     • sub-category (a)
     • sub-category (b)
   • Aircraft-carriers:
     • sub-category (a)
     • sub-category (b)
   • Light surface vessels:
     • sub-category (a)
     • sub-category (b)
     • sub-category (c)
   • Submarines.

2. Not less than four months before the date of the laying of the keel, the following particulars in respect of each such vessel:

   • Name of designation;
   • Category and sub-category;
   • Standard displacement in tons and metric tons;
   • Length at waterline at standard displacement;
   • Extreme beam at or below waterline at standard displacement;
   • Mean draught at standard displacement;
   • Designed horse-power;
   • Designed speed;
   • Type of machinery;
   • Type of fuel;
   • Number and calibre of all guns of 3 in. (76 mm.) calibre and above;
   • Approximate number of guns of less than 3 in. (76 mm.) calibre;
   • Number of torpedo tubes;
   • Whether designed to lay mines;
   • Approximate number of aircraft for which provision is to be made.

3. As soon as possible after the laying-down of the keel of each such vessel, the date on which it was laid.

4. Within one month after the date of completion of each such vessel, the date of completion together with all the particulars specified in paragraph (b) above relating to the vessel on completion.

5. Annually during the month of January, in respect of vessels belonging to the categories and sub-categories mentioned in paragraph (a) above:

   1. Information as to any important alterations which it may have proved necessary to make during the preceding year in vessels under construction, in so far as these alterations affect the particulars mentioned in paragraph (b) above.
   2. Information as to any important alterations made during the preceding year in vessels previously completed, in so far as these alterations affect the particulars mentioned in paragraph (b) above.
   3. Information concerning vessels which may have been scrapped or otherwise disposed of during the preceding year. If such vessels are not scrapped, sufficient information shall be given to enable their new status and condition to be determined.
7. Not less than four months before undertaking such alterations as would cause a completed vessel to come within one of the categories or sub-categories mentioned in paragraph (a) above, or such alterations as would cause a vessel to change from one to another of the said categories or sub-categories: information as to her intended characteristics as specified in paragraph (b) above.

No vessel coming within the categories or sub-categories mentioned in Article 12(a) shall be laid down by any High Contracting Party until after the expiration of a period of four months both from the date on which the Annual Programme in which the vessel is included, and from the date on which the particulars in respect of that vessel prescribed by Article 12(b), have reached all the other High Contracting Parties.

If a High Contracting Party intends to acquire a completed or partially completed vessel coming within the categories or sub-categories mentioned in Article 12(a), that vessel shall be declared at the same time and in the same manner as the vessels included in the Annual Programme prescribed in the said Article. No such vessel shall be acquired until after the expiration of a period of four months from the date on which such declaration has reached all the other High Contracting Parties. The particulars mentioned in Article 12(b), together with the date on which the keel was laid, shall be furnished in respect of such vessel so as to reach all the other High Contracting Parties within one month after the date on which the contract for the acquisition of the vessel was signed. The particulars mentioned inn Article 12(d), (e) and (f) shall be given as therein prescribed.

At the time of communicating the Annual Programme prescribed by Article 12(a), each High Contracting Party shall inform all the other High Contracting Parties of all vessels included in his previous Annual Programmes and declarations that have not yet been laid down or acquired, but which it is the intention to lay down or acquire during the period covered by the first mentioned Annual Programme.

If, before the keel of any vessel coming within the categories or sub-categories mentioned in Article 12(a) is laid, any important modification is made in the particulars regarding her which have been communicated under Article 12(b), information concerning this modification shall be given, and the laying of the keel shall be deferred until at least four months after this information has reached all the other High Contracting Parties.

No High Contracting Party shall lay down or acquire any vessel of the categories or sub-categories mentioned in Article 12(a), which has not previously been included in his Annual Programme of construction or declaration of acquisition for the current year or in any earlier Annual Programme or declaration.

If the construction, modernisation or reconstruction of any vessel coming within the categories or sub-categories mentioned in Article 12(a), which is for the order of a Power not a party to the present Treaty, is undertaken within the jurisdiction of any High Contracting Party, he shall promptly inform all the other High Contracting Parties of the date of the signing of the contract and shall also give as soon as possible in respect of the vessel all the information mentioned in Article 12(b), (c) and (d).

Each High Contracting Party shall give lists of all his minor war vessels and auxiliary vessels with their characteristics, as enumerated in Article 12(b), and information as to the particular service for which they are intended, so as to reach all the other High Contracting Parties within one month after the date of the coming into force of the present Treaty; and, so as to reach all the other High Contracting Parties within the month of January in each subsequent year, any amendments in the lists and changes in the information.

Each of the High Contracting Parties shall communicate to each of the other High Contracting Parties, so as to reach the latter within one month after the date of the coming into force of the present Treaty, particulars, as mentioned in Article 12(b), of all vessels of the categories or sub-categories mentioned in Article 12(a), which are then under construction for him, whether or not such vessels are being constructed within his own jurisdiction, together with similar particulars relating to any such vessels then under construction within his own jurisdiction for a Power not a party to the present Treaty.

1. At the time of communicating his initial Annual Programme of construction and declaration of acquisition, each High Contracting Party shall inform each of the other High Contracting Parties of any vessels of the categories or sub-categories mentioned in Article 12(a) which have been previously authorised and which it is the intention to lay down or acquire during the period covered by the said Programme.

2. Nothing in this Part of the present Treaty shall prevent any High Contracting Party from laying down or acquiring, at any time during the four months following the date of the coming into force of the Treaty, any vessel included, or to be included, in his initial Annual Programme of construction or declaration of acquisition, or previously authorised, provided that the information prescribed by Article 12(b) concerning each vessel shall be communicated so as to reach all the other High Contracting Parties within one month after the date of the coming into force of the present Treaty.

3. If the present Treaty should not come into force before 1 May 1937, the initial Annual Programme of construction and declaration of acquisition, to be communicated under Articles 12(a) and 14 shall reach all the other High Contracting Parties within one month after the date of the coming into force of the present Treaty.

No High Contracting Party shall, by gift, sale or any mode of transfer, dispose of any of his surface vessels of war or submarines in such a manner that such vessel may become a surface vessel of war or a submarine in any foreign navy. This provision shall not apply to auxiliary vessels.

1. Nothing in the present Treaty shall prejudice the right of any High Contracting Party, in the event of loss or accidental destruction of a vessel, before the vessel in question has become over-age, to replace such vessel by a vessel of the same category or sub-category as soon as the particulars of the new vessel mentioned in Article 12(b) shall have reached all the other High Contracting Parties.

2. The provisions of the preceding paragraph shall also govern the immediate replacement, in such circumstances, of a light surface vessel of sub-category (b) exceeding 8,000 tons (8,128 metric tons) standard displacement, or of a light surface vessel of sub-category (a), before the vessel in question has become over-age, by a light surface vessel of the same sub-category of any standard displacement up to 10,000 tons (10,160 metric tons).

1. If any High Contracting Party should become engaged in war, such High Contracting Party may, if he considers the naval requirements of his defence are materially affected, suspend, in so far as he is concerned, any or all of the obligations of the present Treaty, provided that he shall promptly notify the other High Contracting Parties that the circumstances require such suspension, and shall specify the obligations it is considered necessary to suspend.

2. The other High Contracting Parties shall in such case promptly consult together, and shall examine the situation thus presented with a view to agreeing as to the obligations of the present Treaty, if any, which each of the said High Contracting Parties may suspend. Should such consultation not produce agreement, any of the said High Contracting Parties may suspend, in so far as he is concerned, any or all of the obligations of the present Treaty, provided that he shall promptly give notice to the other High Contracting Parties of the obligations which it is considered necessary to suspend.

3. On the cessation of hostilities, the High Contracting Parties shall consult together with a view to fixing a date upon which the obligations of the Treaty which have been suspended shall again become operative, and to agreeing upon any amendments in the present Treaty which may be considered necessary.

1. In the event of any vessel not in conformity with the limitations and restrictions as to standard displacement and armament prescribed by Articles 4, 5 and 7 of the present Treaty being authorised, constructed or acquired by a Power not a party to the present Treaty, each High Contracting Party reserves the right to depart if, and to the extent to which, he considers such departures necessary in order to meet the requirements of his national security;

   1. During the remaining period of the Treaty, from the limitations and restrictions of Articles 3, 4, 5, 6(1) and 7, and
   2. During the current year, from his Annual Programmes of construction and declarations of acquisition.

   This right shall be exercised in accordance with the following provisions:

2. Any High Contracting Party who considers it necessary that such right should be exercised, shall notify the other High Contracting Parties to that effect, stating precisely the nature and extent of the proposed departures and the reasons therefor.

3. The High Contracting Parties shall thereupon consult together and endeavour to reach an agreement with a view to reducing to a minimum the extent of the departures which may be made.

4. On the expiration of a period of three months from the date of the first of any notifications which may have been given under paragraph (2) above, each of the High Contracting Parties shall, subject to any agreement which may have been reached to the contrary, be entitled to depart during the remaining period of the present Treaty from the limitations and restrictions prescribed in Articles 3, 4, 5, 6(1) and 7 thereof.

5. On the expiration of the period mentioned in the preceding paragraph, any High Contracting Party shall be at liberty, subject to any agreement which may have been reached during the consultations provided for in paragraph (3) above, and on informing all the other High Contracting Parties, to depart from his Annual Programmes of construction and declarations of acquisition and to alter the characteristics of any vessels building or which have already appeared in his Programmes or declarations.

6. In such event, no delay in the acquisition, the laying of the keel, or the altering of any vessel shall be necessary by reason of any of the provisions of Part III of the present Treaty. The particulars mentioned in Article 12(b) shall, however, be communicated to all the other High Contracting Parties before the keels of any vessels are laid. In the case of acquisition, information relating to the vessel shall be given under the provisions of Article 14.

1. If the requirements of the national security of any High Contracting Party should, in his opinion, be materially affected by any change of circumstances, other than those provided for in Articles 6(2), 24 and 25 of the present Treaty, such High Contracting Party shall have the right to depart for the current year from his Annual Programmes of construction and declarations of acquisition. The amount of construction by any Party to the Treaty, within the limitations and restrictions thereof, shall not, however, constitute a change of circumstances for the purposes of the present Article. The abovementioned right shall be exercised in accordance with the following provisions:

2. Such High Contracting Party shall, if he desires to exercise the abovementioned right, notify all the other High Contracting Parties to that effect, stating in what respects he proposes to depart from his Annual Programmes of construction and declarations of acquisition, giving reasons for the proposed departure.

3. The High Contracting Parties will thereupon consult together with a view to agreement as to whether any departures are necessary in order to meet the situation.

4. On the expiration of a period of three months from the date of the first of any notifications which may have been given under paragraph (2) above, each of the High Contracting Parties shall, subject to any agreement which may have been reached to the contrary, be entitled to depart from his Annual Programmes of construction and declarations of acquisition, provided notice is promptly given to the other High Contracting Parties stating precisely in what respects he proposes so to depart.

5. In such event, no delay in the acquisition, the laying of the keel, or the altering of any vessel shall be necessary by reason of any of the provisions of Part III of the present Treaty. The particulars mentioned in Article 12(b) shall, however, be communicated to all the other High Contracting Parties before the keels of any vessels are laid. In the case of acquisition, information relating to the vessels shall be given under the provisions of Article 14.

At the moment of signing the Treaty bearing this day's date, the undersigned, duly authorised to that effect by their respective Governments, have agreed as follows:

1. If, before the coming into force of the abovementioned Treaty, the naval construction of any Power, or any change of circumstances, should appear likely to render undesirable the coming into force of the Treaty in its present form, the Powers on behalf of which the Treaty has been signed will consult as to whether it is desirable to modify any of its terms to meet the situation thus presented.

2. In the event of the Treaty not coming into force on 1 January 1937, the abovementioned Powers will, as a temporary measure, promptly communicate to one another, after the laying down, acquisition, or completion of any vessels in the categories or sub-categories mentioned in Article 12(a) of the Treaty, the information detailed below concerning all such vessels laid down between 1 January 1937 and the date of the coming into force of the Treaty, provided, however, that this obligation shall not continue after 1 July 1937:

   • Name or designation;
   • Classification of the vessel;
   • Standard displacement in tons and metric tons;
   • Principal dimensions at standard displacement, namely length at waterline and extreme beam at or below waterline;
   • Mean draught at standard displacement;
   • Calibre of the largest gun.

3. The present Protocol, of which the French and English texts shall both be equally authentic, shall come into force on this day's date. It shall be deposited in the archives of His Majesty's Government in the United Kingdom of Great Britain and Northern Ireland which will transmit certified copies thereof to the Governments of the countries for which the Treaty for the Limitation and Reduction of Naval Armament was signed in London on 22 April 1930.

IN FAITH WHEREOF the abovenamed Plenipotentiaries have signed the present Protocol and have affixed thereto their seals.

DONE in London the 25th day of March, nineteen hundred and thirty-six.

[Signatures omitted.]