Torpedo photos & information

Whitehead Mk 2 & Mk 3

The Whitehead Mk 2 and Mk 3 weapons were actually a surface ship design adapted later for submarine use. They were powered by a three-cylinder radial engine run on compressed air. They were so similar in configuration that it was hard to tell them apart. Indeed, they had the exact same operational parameters. However, the big difference is that the Mk3 was the first USN torpedo to use a gyroscope for azimuth control. This reduced deviation from left or right of planned track from 24 yards to just 8 yards. That is still a big margin, but in those early days it was quite impressive accuracy.

Whitehead Mk 3 torpedoes stored at the weapons depot at Naval Station Cavite, Philippines, approximately 1906. The wheeled carts allowed the quick movement of the weapons from storage to the pier.

Photo in the private collection of Ric Hedman.

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  Photo NH 90188 courtesy of the NHHC.

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  U.S. Navy photo.

Navy photos of a Mk 3 weapon being loaded into the USS A-2 (Submarine No. 3) at Naval Station Cavite, Philippines, circa 1912. The sailor manhandling the weapon down the hatch gives a good sense of scale to the torpedo, and illustrates how short the mid-body was compared to later torpedoes. Our early submarines were restricted to the use of these short weapons because they were the only ones that would fit inside the boats and the tubes they used. That would quickly change.

Bliss-Leavitt Mk 4 Mod 1

The Bliss-Leavitt Mk 4 was the first torpedo specifically designed for submarine use. The surface navy had begun the transition to larger 21" diameter torps, but they would not fit in the restricted spaces of the submarines of the time, thus the BL Mk 3 was scaled down to 17.7" for submarine use. It was 57 inches longer than the Mk 3, enabling a larger air flask that stored air at a much higher pressure. The propulsion system was vastly different from the earlier Whitehead weapons in that the Mk 4 used a vertical turbine spun by compressed air from the flask heated by an alcohol burner. The heated air gave it more energy and when combined with the turbine it increased the speed and range of the weapon.

D-3 hoisting aboard a Mk 4 torpedo that it as just recovered from a practice shot, circa 1912. This photo gives a good view of the aft end of the weapon, including the control surfaces and the twin contra-rotating propellers. The twin propellers spinning in opposite directions eliminated roll torque, preventing the weapon from cork-screwing along its longitudinal axis. Eliminating the roll torque also allowed the gyro to maintain a more accurate course.

Another view of the operation shown above. There is a snubbing line attached to the aft end of the weapon, looped around the #1 periscope. This line allowed the weapon to be gently and carefully lowered into the torpedo room.

Bliss-Leavitt Mk 6

Mostly a cruiser/destroyer torpedo, the Mk 6 was used briefly by E through H-class submarines until the more capable Mk 7 came along. In overall external appearance the Mk 6 was quite similar to the Mk 7. The Mk 6 introduced a horizontal turbine arrangement for the engine, one that would become standard for all subsequent torpedo engine designs. It was also the first Bliss-Leavitt design to move the control surfaces forward of the propellers. Improvements in gyroscopic control systems and the higher speed of this torpedo rendered the more complicated arrangement of having the control surfaces aft of the propellers unnecessary. This would become another standard feature on all subsequent USN designs. Sources indicate that only about 100 of these weapons were produced.

Currently, PigBoats.COM does not have a good picture of a Mk 6. An idea for its appearance can be gained from the Mk 7 pictures below.

Bliss-Leavitt Mk 7

The Mk 7 torpedo introduced the "wet-heater" steam engine. This feature added a jet of seawater that was injected into the heated air stream, producing steam. With steam having much greater energy than simple heated air, the torpedo engine had more power and more range. The disadvantage is that it left a bubbly wake behind the weapons as it traveled through the water, potentially alerting the enemy to its presence. Despite this, the wet-heater type engine became the standard for USN torpedoes until the introduction of the Mk 18 electric in 1943.

In 1922 the Navy undertook a purge of older torpedoes in an effort to simplify the supply chain and ease training issues. All torpedoes prior to the Mk 7 were recalled and removed from service. As we moved towards WWII the Mk 7 was showing its age, but it was retained so that the Navy could equip the old O-class boats that were being brought out of reserve to train new submarine crews. It was the last 18" torpedo used by the Navy.

Bliss produced four additional versions of the Mk 7 for use as aircraft dropped torpedoes. These were pulled out of service when the new Mk 13 was introduced in 1938.

A Mk 7 torpedo on a cart at NTS Newport, August 1913. Overall, it was virtually identical to the Mk 6 in appearance, but it was equipped the the more powerful wet-heater engine. Note the control surfaces forward of the twin contra-rotating propellers. It was a good weapon, but was considered to have an underpowered warhead at only 205 lbs of TNT.

Photo courtesy of the NHHC.

Mk 7's being loaded onto the L-2 (Submarine No. 41) and L-4 (Submarine No. 43) while in drydock in Bantry Bay Ireland, 1918. The weapon in on the skid and a snubbing line is noosed around the tail. The snubbing line is wrapped around #1 periscope, using the scope as a block to assist lowering the weapon into the torpedo room. The crewman in the peacoat and watch cap right at the aft end of the torpedo is standing on the retracted 3"/23 caliber Mk 9 deck gun.

Photo courtesy of NARA and Navsource.

K-5 (Submarine No. 36) with a retrieved Mk 7 exercise shot on deck, early 1920's. The explosive warhead has been removed and a water filled inert warhead has replaced it. Torpedoes were very expensive, so there was a great deal of emphasis on retrieving them and reusing them after a peacetime training exercise. At the end of the run, the remaining air in the weapon's air flask would be used to blow the water out of the practice warhead, allowing the weapon to float so that it could be retrieved by the boat that fired it. It only took a half-hour or so to replace the practice head with the real thing if needed.

Photo in the private collection of Ric Hedman.

Bliss-Leavitt Mk 9 Mod 1B

The USN was desirous of a step up in speed, range, and power of its torpedoes and during World War I they decided to standardize on 21" diameter weapons. The first 21" weapon produced was the Bliss-Leavitt Mk 8, built in quantity for the Caldwell, Wickes, and Clemson-class "flush-deck four-pipe" destroyers built during WWI.

Bliss-Leavitt/BuOrd Mk 10 Mod 3

BuOrd Mk 14

Westinghouse Mk 18 Mod 1

BuOrd Mk 23

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