engine-room space is between 13 and 20 per cent-and for paddle-wheel steamers whose engineroom space is between 20 and 30 per cent of the entire space included within gross tonnage. The deductions for propelling power in the case of screw and paddle-wheel steamers whose enginc-room space does not exceed the 13 or 20 per cent limits are determined by the Danube rule in Great Britain, unless the owner and Board of Trade agree to apply the percentage rule. It is the practice of the Board of Trade to require the application of the Danube rule in such cases. In the United States the law requires the deductions for propelling power to be made in accordance with the Danube rule in the case of low-powered steamers under the 13 and 20 per cent limits. In Germany such steamers have their propelling power deductions made in accordance with the Danube rule, unless the Bureau of Registry orders the measurement boards to apply the percentage rule. It is the practice of the German authorities to apply the same rule that the Board of Trade adheres to. In all three countries the deduction for propelling power, in the case of vessels whose engine-room space is 20 per cent or more (in the case of paddle-wheel steamers 30 per cent or more) of the space included in gross tonnage, is determined by the application of the percentage rule or Danube rule, as the owner of the vessel may prefer.

The measurement rules of the Suez Canal Co. require propelling power deductions to be made in accordance with the Danube rule in the case of all vessels with movable bunkers. The owners of vessels with fixed bunkers may choose whether the propelling power deduction shall be made by applying the Danube rule or by measuring the actual space occupied by the engine room and bunkers. In practice the Danube rule is almost always applied. It is somewhat more favorable to the shipowner than the actual measurement rule would be. The Suez Canal Co. never makes propelling power deductions in accordance with the percentage rule.

The maximum deduction for propelling power, except in the case of tugs, is limited by the Suez rules to 50 per cent of the gross tonnage. In Great Britain, on and after January 1, 1914, the maximum deduction allowed, except for tugs, will be 55 per cent of the tonnage remaining after deductions other than those for propelling power have been made. The American and German rules contain no limitations as to the maximum amount that may be deducted from gross tonnage in the calculation of net tonnage.

The British, Suez, German, and American rules concerning deductions for navigation spaces other than for propelling power contain so many details that the provisions of the several laws may best be compared by summarizing the provisions in tabular form. Table IV states how the several spaces used for navigation, for the accommodation of the crew, and for stores are dealt with in each of the measurement rules under consideration.

TABLE IV.–Deductions other than for propelling power under the measurement rules of Great Britain, the Suez Canal Co., Germany, and the United States.

1 The following and all other general deductions may not in the aggregate exceed 5 per cent of the gross tonnage for Suez navigation. The 5 per cent does not include the light and air spaces above the engine room. In the United Kingdom, Germany, and the United States the national rules provide no maximum limit other than that the spaces deducted shall be reasonable in size for their intended purposes.

TABLE IV.-Deductions other than for propelling power under the measurement rules of Great Britain, the Suez Canal Co., Germany, and the United States-Continued.

Table IV indicates that crew spaces are deducted by all four sets of measurement rules, but the several rules differ as to the minimum amount of space that must be given each member of the crew. The Suez rules, it will be noted, limit the deductions for spaces, other than those required for propelling power, to 5 per cent of the space included within gross tonnage.

All rules provide for the deduction of officers' and engineers' accommodations, including cabins, berths, and mess rooms. The Suez rules, however, are less liberal than the others in this regard. The cabins occupied by the master, purser, clerk, and, in the case of passenger steamers, by the stewards and cooks, are not deducted in calculating net tonnage. The Suez rules permit the doctor's cabin to be deducted only when the cabin is actually occupied by the doctor.

The spaces occupied by galleys, bakeries, toilets and bathrooms for the accommodation of the crew, officers, and engineers, are not included in net tonnage. Under the Suez rules such spaces are deducted whether situated above or below deck, but under the British, German, and American rules these spaces are deducted only when located below deck, for the reason that when such spaces are above deck they are not included in the gross tonnage.

Spaces occupied by the steering gear, chain locker, houses for charts, signals, and other instruments of navigation, lookout houses, houses for donkey boiler and engine connected with the main pumps are deducted from gross tonnage by the British, German, and American rules when such spaces are below decks. If the spaces are above decks they are exempted from measurement under the three national rules. The Suez rules deduct these spaces whether located above or below deck. The space occupied by the donkey engine and boiler when connected with the engine room is by the British, German, and American rules deducted as a part of the engine room space. When the donkey engine and boiler are not connected with the engine room the space occupied by them is not measured if it is above deck. Under the Suez rules, however, the donkey engine and boiler, when located above deck, are measured into gross tonnage and deducted therefrom, if they are connected with the pumps, steering gear, or anchor gear, and are not used for hoisting cargo.

Spaces required for boatswains' stores are deducted by the British, German, and American rules, but not by the Suez rules.

The rules regarding the deductions for light and air and funnel spaces above the engine room are confusing. The British and German rules agree in deducting those spaces below the upper deck and in deducting a part of those spaces above the upper deck upon request of the owner of the vessel. The American rules provide for the deduction of the entire light and air and funnel space above the upper deck when the owner requests that space to be included in the engine room. The Suez rules provide for the deduction of the entire light and air and funnel space if the owner of the vessel desires to accept the conditions that accompany such deduction. When the deductions are made by the measurement of actual engine room and fuel spaces, the entire light and air and funnel spaces are included in the deductions under the Suez rules.

The British and American rules deduct passageways when they serve deducted spaces exclusively. The German rules deduct passageways serving crew, engineers' or officers' quarters, while the Suez rules do not deduct passageways unless they are fitted with lockers, hammocks, etc., for the use of the ship's personnel, nor unless they serve the quarters occupied by the personnel. In the three national rules sailing vessels are allowed to deduct 24 per cent of the gross tonnage for spaces in which to stow the sails, but this deduction is not permitted by the Suez regulations.

Water-ballast spaces, other than double-bottom tanks, are deducted under the British, German, and American rules, but not under the Suez regulations. Double-bottom ballast spaces not available for freight, stores, or fuel are exempted by the three national rules. The Suez rules exempt double-bottom spaces from measurement.

The foregoing comparisons of the provisions of the British, Suez, German, and American rules show very clearly that the deductions allowed by the Suez rules are less than those provided for in the three national rules. This, together with the fact that the Suez rules include within gross tonnage more spaces than are included by the British and German rules, accounts for the higher net tonnage given vessels by the Suez than by British or German measurement rules. Moreover, the net tonnage of most vessels when measured by the Suez rules will be larger than when measured by the American rules.

By applying to the same vessel each of the four rules, the differences in the results can be clearly shown. In 1911, the United States Commissioner of Navigation had the admeasurers

at New York apply to eight vessels the British, Suez, and American rules. To two other vessels having German certificates, the Suez and American rules were applied. The note appended to this chapter gives the details of the deductions made from gross tonnage by applying to eight vessels the British, Suez, and American rules and by applying to two vessels the German, Suez, and American rules. Table V states the gross and net tonnage as determined by the British, American, and Suez rules of the eight vessels to which those rules were applied:

TABLE V.-Gross and net tonnage of eight steamers as determined by the British, American, and Suez measurement rules.

The first of the eight ships mentioned in Table V, the Kentuckian, is of American build and registry, and is one of the fleet that will be operated by the American-Hawaiian Steamship Co. through the Panama Canal. The gross tonnage of this vessel is practically the same under all three rules, British, American, and Suez, and the deductions made from gross tonnage to determine net tonnage are nearly the same under the British and American rules. The Suez net tonnage is greater than the British or American, mainly because of the larger deduction for propelling power authorized by the American and British rules. The 32 per cent rule makes the propelling power deduction in Great Britain and the United States 2,084 tons, as compared with a deduction of 1,496 tons resulting under the Suez regulations from the application of the Danube rule.

The seven vessels other than the Kentuckian listed in Table V are all of British registry. The Voltaire has the same gross and net tonnage under the British and American rules. The Suez rules give the vesseľ a somewhat greater gross tonnage and a much larger net tonnage. The propelling power deduction under the 32 per cent rule is 2,757 tons, as compared with a deduction of 2,035 tons under the Danube rule.

The British steamship Stephen, mentioned in the table, affords a good illustration of the extent to which different definitions of open and closed spaces may affect gross and net tonnage. The tonnage openings in the uppermost or so-called shelter deck of the Stephen caused the space between that deck and the main deck of the vessel to be considered open under the British rules and thus exempted from measurement, whereas under the American and Suez rules this large space between the two decks is included within gross and thus within the net tonnage. The gross tonnage of the Stephen under British measurement is 4,434 tons, while under the American rules the tonnage is 5,470, and under the Suez rules 5,477. If this vessel had the same gross tonnage under the British and American rules, it would have the same net tonnage under those two rules. The Suez net tonnage of the Stephen is higher than the British or American, because in determining the Suez tonnage the propelling power space is deducted by applying the Danube rule.

The details regarding the measurement of the Santa Rosalia give another illustration of the effect which gross tonnage may have upon the net tonnage. Gross tonnage being 424 tons less by the British rules than by the American rules, the engine-room space is equal to over 13 per cent of the entire space included in gross tonnage under the British rules, whereas under

the American rules, the gross tonnage being larger, the engine-room space is less than 13 per cent of the gross tonnage and the propelling power deduction is made under the Danube rule. The note appended to the end of this chapter, which states in detail the deductions made from gross tonnage, may be consulted for an explanation of the differences in the net tonnage as determined by the British, American, and Suez rules in the case of the Kirkdale, Ikala, Tunstall, and Benwood, listed in Table V.

The average gross tonnage of the eight vessels listed in Table V is lowest under the British rules and highest under the American rules. The average net tonnage as determined by the American rules is about midway between the average under the British and Suez

measurements.

The gross and net tonnage of two German steamers, the Patricia and Duisburg, as determined by the German, American, and Suez rules are compared in Table VI.

TABLE VI. Gross and net tonnage of two German steamers as determined by the German, American, and Suez measurement

It will be seen by studying the details in the note appended to this chapter that the German and American rules authorize much larger deductions than do the Suez rules both for propelling power and crew space in the case of the steamer Patricia mentioned in Table VI. Under the Suez rules, the deductions for the space occupied by the crew, officers, and engineers was 234 tons (697 cubic meters) less than the deduction made under the German and American rules. The propelling power deduction under the percentage rule was 1,600 tons greater than under the Danube or Suez rule.

The other German steamer mentioned in Table VI, the Duisburg, is given a larger gross tonnage under the American and Suez rules than under the German, because the German rules treat as "open" certain spaces under the so-called shelter deck-spaces that are included in the American and Suez gross tonnage. The net tonnage of the Duisburg under the American rules is less than under the Suez rules, mainly because of the different deductions made for propelling power. The 32 per cent rule was applied by the American rules, whereas the Suez deductions were made in accordance with the Danube rule.

The dissimilarity in the ratio of gross and net tonnage of vessels as measured and registered under the laws of different countries is brought out by Table VII, which states the aggregate gross and net tonnage of the metal steam vessels of each of the several commercial nations of the world for the years 1890, 1900, and 1910. For convenience of comparison, the gross and net tonnages of the Suez Canal for the three years are added to the table.

1 This table is taken from the report of the United States Commissioner of Navigation for the year 1911.