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mend the immediate purchase of five of that type. The record of No. 2 propeller tests was submitted purely with the frank intent of showing the peculiarities and inefficiency of the screws which expert judgment had prescribed. That rec- ord, however, has been circulated in many countries, and many people, not aware of the true conditions, have been led to believe that those figures were really the Protector's trial fig- ures as actually determined by the United States naval board of inspec- tion and survey. As a matter of fact, those figures were nothing like as good as the boat had previously made, nor as good as she did on her trials 4VO. L 'TAE Marine REVIEW Lieutenant 'Gadd, with the assistance of the following representa- tives of the Naval Technical Committee: Captain Zalessky, Head Ship Builders' Asst., Mr. Gavliloff, Head Machinist's Asst., Mr. Karpoff. The run of Sept. 28 from Kronstadt to and over the measured mile, and from there to the place of the principal trials in Bjorko sound, was made quite successfully. In the above run both gasoline engines were used alone working with benzine, except over the 'measured mile, when the engines worked in conjunction with the motors. The average speed of the run was, at 248 revolutions, at the rate' of 6.75 knots. On the measured mile the inventor adjusted the propellers at the most advantageous pitch. The engines worked during the entire run with- out any trouble. After arrival at Biorko sound, alongside of the schoolship Oprychnik, a diver was sent out from the diving compartment of the Osetr to a depth of five fathoms and executed suc- cessfully the order given by the commission, consisting of picking up and handing into the compartment an electric lamp which had been lowered from the Oprychnik. The following trials were made on Sept. 26: 'VO. 2 Diameter, 45 in. Pitch, 3. ft 0: in: Developed Blade Area, 56.3 per cent of Disc. abroad preliminary to her acceptance by the Russian government. Upon the departure of the board in January, 1904, the Protector was docked and an opportunity taken to convert the improved screws into old junk. The speaker then designed a screw of still greater diameter, but as I have already stated, I am not a propeller expert, and while these No. 3 screws gave better results than screws No. 2, their. efficiency was not as great as that of the screws originally fitted to the boat. -These No. 3 screws were the ones, however, used on the official -- trials, preliminary to the acceptance of the Protector by the Russian au- thorities. I beg the indulgence of this society while I read that report. OFFICIAL RUSSIAN REPORT UPON TRIAL OF THE LAKE BOAT PROTECTOR, NOW THE OSETR OF THE RUSSIAN NAVY. On the 25th, 26th, 27th, and 28th of Sep- tember, 1904 (old style), the commission ap- pointed. by the general staff of the Imperial Russian marine on Sept. 11, 1904, under Order No. 16,094, directed the trials of the torpedo boat Osetr during the run from Kronstadt to Bjorko sound and'in Biorko sound itself. The commission, under the presidency of Commander M. Becklemicheff, was composed of the following members: Commander Golovnine, Lieutenant von Schulz, 4th, Diameter, 49 in. Pitch, 4 ft. 0 in. Developed Blade Area, 65 per cent of Disc. The transition from the position on the sur- face (normal. cruising condition) to the awash, or half submerged condition (war-time cruising ~ condition) was made in eleven minutes, by fill- ing the superstructure by means of pumps. In this condition the deck. of the superstructure is on a level with the surface of the water. After that the check valves of the ballast tanks were opened and tank No. 1°' forward and tank No. 1 aft were filled with water. The time required for filling was between two and three minutes. The boat submerged to the top of the conning-tower. In this condition the sensibility of the boat to the longitudinal chang- 'ing of weights was as follows: 20 puds (720 lbs.), moved for a distance of 20 ft., produced an inclination of 3%. Then the boat was sent ahead, and the time required for the distance of 0.88 miles, in a completely submerged condition, at' the forced speed of the motors, was 914 minutes; that is, . the speed was 5.6 knots. . : \ From the last mentioned position, the speed of descent was determined. Six fathoms of the anchor's cables having been released, and the central ballast tank having been filled, the boat descended in 58 seconds to a depth of 62 ft. On the same day a trial was made of firing wooden blocks (dummy torpedoes) from the for- ward torpedo tubes by means of air pressure, in war-cruising (awash) condition. The trial was quite successful. No change in the trim of the boat was observed. A firing pressure of 60 lbs. was used. A trial of running on wheels was made. This without doubt is quite possible on a smooth bottom, and the passage of the wheels over small stones was successfully executed. The commission considers the wheels very useful to 'prevent injury to the hull of the boat. On Sept. 27 the following runs were made on the measured distance of 0.88 miles, and the speeds were as follows: s ; (1) Normal cruising condition, engines only, 8%4 knots, at 240 revolutions. -- : (2) Normal cruising condition, engines and motors combined, 9.3 knots, at 300 revolutions. 29 3) War, cruising condition (conning-tower aes engines only, 7.4 knots, at 224 revolu- ions. , _(4) Submerged, motors only, at the normal discharge rate, 5.4 knots, at a pitch of 2% ft., 300 amperes and 115 volts. (The full speed submierged was slightly over six knots.) The change from the engines to the motors was made in 15 seconds. tus The time consumed in passing from the war- cruising (awash) condition' of the boat under engines, conning-tower only above the water, to the totally submerged condition, with motors, was 1 minute 55 seconds. In addition trials of trolling, or grappling for mines through the cock in the diving-door, while running along the bottom, were made. . The. difficulty of such work on a rocky bottom was shown, and success on a rocky and irregular bottom is very doubtful. | eo : : In view of the above résults, the commission decided as follows: 4 The boat maneuvers easily, maintains well uni- | form depth, and is suitable for coast defense: The boat can be accepted by the government after the teaching of the crew. In addition, the commission considers the fol- lowing repairs and changes as necessary; (1) To tighten the air compréssor. MOn . Diameter, 61 in. Pitch, +3. it..6. in. Developed Blade Area, 33.5. per cent of Disc. (2) To change the wood in the port side' clutches. : : (3) To supply the boat with a new omni- scope. (Still later pattern.) : ' (4). To replace part of the wooden bulkhead on on which the rheostat is fitted with non-com- ~ bustible material--asbestos or slate. (5) To present drawings of the boat, Me 2 motors and other details. : (Signed by the president and members of the commission and the representatives of the © Naval Technical Committee assisting. ) Poe, From this report it will be seen that Mr. Spear's tables at least so far as they relate to the Protector, are unre- If Mr. Spear, will submit the -- liable. full report of the Russian trials of the Fulton and those of other competing types tried by the Russian naval au--- thorities, perhaps better and more ac- curate deductions could be drawn as to the relative efficiency of the different -- 'boats tested by the imperial authori-. ties. - \ In the speaker's. judgment speed is not the first. essential in a successful submarine boat. navy department, in 1893, when asking inventors to submit designs for un- der-water craft, placed safety at the head of the requirements. The order 'of importance in which the various -- elements were officially given, was as follows: oe ae The United States