(c) A mess room, if there is one, for the exclusive use of the officers and engineers; or, if they exist, two mess rooms, one of them for the exclusive use of the officers, the other one for the exclusive use of the engineers. A mess room, if there is one, for the exclusive use of the petty officers. No deduction is allowed for the officers' mess room in ships having passenger accommodation, which are not also provided with a passengers' mess room.

(d) All spaces fitted as bathrooms, or lavatories, for the exclusive use of the ship's officers, engineers, and crew, with the exception of such of the said bathrooms as is available for passengers when no bathroom for their exclusive use is provided.

(e) All spaces specially provided for the storage of electric searchlights and wireless telegraphy appliances, on condition that they are situated on the upper deck.

The above specified spaces can only be deducted if they bear a distinctly visible and permanent indication of their exclusive appropriation.

MEASUREMENT OF DECK SPACES.

For vessels fitted with superstructure the following rules,1 which concern only such spaces as are excluded from the national tonnage, are applied:

I.-Ships with one tier of superstructures only.

1. Poop, bridge, forecastle. The following exemptions are allowed:

(a) Such length of the poop measured from the inside of the stern timber, at half height of the said poop, as shall be equal to one-tenth of the full length of the ship.

(b) The portion of the bridge in way of the air spaces of the engine and boiler spaces, it being understood that such air spaces are not considered to extend beyond the forward bulkhead of the stokehold and the after bulkhead of the main engine room.

(c) Such length of the forecastle measured from the inside of the stem at half height of the said forecastle, as shall be equal to one-eighth of the full length of the ship.

(d) In each of the above three cases of superstructures, such portions in the walls of the ships as are in way of openings not provided with any means of closing and corresponding to one another.

2. Poop and bridge combined, or forecastle and bridge combined. In each of these combined spaces the following exemptions are allowed:

(a) That length only which corresponds to the openings of the engine room and boiler spaces as specified in (b) above.

(b) Such portions as are in way of openings not provided with any means of closing and corresponding to one another.

3. Shelter decks. In the case of shelter decks the portions in way of openings not provided with any means of closing and corresponding to one another. Such air spaces as are situated within the shelter deck must be measured into the engine-room space and deducted together with 75 per cent of their volume.

II.-Ships having more than one tier of superstructures.

(a) The exemptions prescribed in paragraphs 1, 2, and 3, above, are applicable in their entirety to the lower tier only.

(b) Tiers above the lower tier are only allowed the exemption of such portions as are in way of openings in the side plating of the ship not provided with any means of closing and corresponding to one another.

REMARK.

Should a vessel at any time transit with merchandise of any kind, or bunker coal, or stores of any description, in any portion whatever of any exempted space, the whole of that space is added to the net tonnage and can nevermore be exempted from measurement.

1 Supplementary rules added in 1904.

APPENDIX XIII.

MEMORANDUM BY THE UNIVERSAL MARITIME CANAL COMPANY OF SUEZ ON THE APPLICATION OF THE RULES OF 1904 RELATIVE TO THE MEASUREMENT

OF SUPERSTRUCTURES.-PARIS, 1909.

APPENDIX XIII.

MEMORANDUM BY THE UNIVERSAL MARITIME CANAL CO. OF SUEZ ON THE APPLICATION OF THE RULES OF 1904 RELATIVE TO THE MEASUREMENT OF SUPERSTRUCTURES.

PARIS, 1909.

A. DEFINITION OF THE VARIOUS SPACES ABOVE DECK.

In making out the special tonnage certificate of the Suez Canal, the superstructures to be considered are the following:

1. Isolated spaces.-Poop, bridge, and forecastle.

2. Combined spaces.-Extended poop and extended forecastle.

If the poop and forecastle are united by a continuous roof or deck and by walls likewise continuous to the bridge, the spaces thus united constitute, according to definition, a combined space-extended poop in the first case, and extended forecastle in the second case. A complete break either in the roof or walls reverts the case to the category of isolated spaces.

3. Shelter deck.-The three spaces united into one constitute a shelter deck.

The superstructures may have a single tier or several tiers. The treatment applicable to the first tier is not the same as that applied to the others, and each tier is to be measured separately.

B. DETERMINATION OF THE DECK SPACES TO WHICH THE RULES OF 1904 APPLY.

Under the Rules of 1904, for the determination of Suez tonnage, the spaces hereunder defined are divided into three categories:

First category: Spaces or portions of spaces closed in according to national measurement rules.

These spaces are always included in Suez tonnage; the Rules of 1904 are not applicable to them.

In determining whether or not a space is in this category the Suez Canal Co. accepts the judgment of the national surveyors. Since the Rules adopted in the different countries for the determination of national tonnage are considered as practically identical, the treatment of a space is the same for Suez tonnage whatever may be the flag of the ship.

Second category: Spaces or portions of spaces open according to Suez measurement rules and national measurement rules.

These spaces are not included in the special tonnage certificate of the Suez Canal Co.; the Rules of 1904 are not applicable to them.

According to the Rules of the Commission of Constantinople, the spaces of the second category are:

The spaces under awning decks without other connection with the body of the ship than the props necessary for supporting them, which are not spaces "separated off" and are permanently exposed to the weather and the sea, will not be comprised in the gross tonnage, although they may serve to shelter the ship's crew, the deck passengers, and even merchandise known as "deck loads."

The Suez Canal Co. recognizes in the meantime that a space may be considered as open, and consequently excluded from tonnage, if there is an opening not provided with means of closing, the breadth of which is equal to or greater than half the breadth of the deck opposite the opening, and if the space can not be used to shelter other merchandise than deck cargo.

In order to make this last restriction exact, the company recognizes that the space between the open face and a line drawn parallel to this face at a distance equal to half the width of the deck opposite the opening can not be used to shelter merchandise other than deck cargo, and that the remainder of the space may be used to shelter merchandise other than deck cargo and is not to be considered as open.

On the other hand, if, in the interior of the superstructure, because of any arrangement whatever and at a distance from the open face less than one-half the width of the deck, the opening becomes less than one-half the width of the deck (above indicated), only that portion of the space comprised between the open face and this point is to be considered as belonging to the second category; the remainder of the space falls within the third category.

Furthermore, in order that a space may be considered as open beyond a distance equal to one-half the width of the deck it is necessary that it be actually isolated from the other superstructures. This condition is not to be considered as fulfilled unless the space is separated from the superstructure immediately adjacent by a break (interval) in the roof and in the walls equal to at least half the width of the deck; if the widths of the deck opposite the openings of two adjoining superstructures are different, the smaller width is to be taken.

Third category: Spaces or portions of spaces open according to the national measurement rules, but which are closed-in according to the Suez rules, because they do not fulfill the conditions defined above for the second category.

It is to these spaces that the Rules of 1904 are applicable.

C. NATURE OF THE EXEMPTIONS PERMITTED BY THE RULES OF 1904.

The Rules of 1904 define the portions of the spaces comprised in the third category that may be exempted.

In these definitions the length of the ship indicated is the total length comprised between the interior face of the stem and the interior face of the rear sternpost, the measurement being taken at the half height of the superstructures.

It is, moreover, to be understood, in everything that follows, that in no case shall the exemptions include closed-in spaces or portions of closed-in spaces situated within exemptable parts.

I. SHIPS WITH ONE TIER OF SUPERSTRUCTURES.

1. Isolated spaces.

The exemptions permitted are as follows:

(a) Poop. The portion of this space situated at the stern equal in length to one-tenth of the length of the ship measured from the interior face of the rear sternpost and at half the height of the poop. (Figs. 1 to 4.)1

(b) Bridge. The portion of this space situated in way of the air spaces above the engine room and the boilers, it being understood that such air spaces are not considered to extend beyond the forward bulkhead of the stokehold or the after bulkhead of the main engine room. (Figs. 5 to 8.)

When the air spaces above the engine room and boilers are separated by an interval, the portion of the bridge in way of this interval is exempted. (Figs. 7 and 8.)

The exemption of the portions of the bridge in way of air spaces has the effect of excluding the volume of these air spaces from the tonnage of the ship and therefore from the measurement of the engine room.

1 See plates at end of this appendix.