By keeping on a straight line course the ship is enabled to make a good many more miles on the same number of revolutions or turns of the propeller. Under exactly the same weather conditions a 16,000 ton liner made 370 miles in 24 hours at an average of 86.95 revolutions per minute per mile when steered by a magnetic compass, and the same liner made 377 miles with 85.61 revolutions per minute per mile when steered by the Gyro-Compass. This saving amounts to easily $50 per day for this ship. During her eleven-day voyage she saved $550. At this rate of saving the Gyro-Compass equipment is soon paid for.
The Turbinia was the first turbine steamer.
The Sperry Gyro-Compass does not oscillate with the rolling of the ship, or in other words, has no heeling error. The use of the helm is greatly diminished. Records show that on one trans-Atlantic liner a saving of 24 percent in the revolutions of the steering engine, when steered by Gyro-Compass, was effected. One of the largest trans-Atlantic liners reports that but one-third of the helm is used when the ship is steered by Gyro-Compass.
This saving in the use of the steering engine gives actual proof that the ship navigated by a Gyro-Compass steers a straight line course. It further proves that the ship does not divert its slip-stream as often—the power output of the main engines is thereby reduced.
Records taken on a well-known passenger liner show that in making her regular trip between New York and Jacksonville, Florida, she saved more than two hours due to steering by a Sperry Gyro-Compass. A saving of 3,410 turns of her propeller was also effected. These savings were made even with much greater than the usual draft.
Records taken by means of the Sperry Recording Compass show that when the helmsman is given a certain course he can keep the ship one and one-half degrees nearer the course when steering by the Gyro-Compass than when steering by magnetic compass.
The Gyro-Compass can make great savings in money both in construction and operation of the ship. These factors are perhaps trivial when compared with the safety factor introduced by the use of the Sperry Gyro-Compass.
Due to the elimination of the many uncertainties of the magnetic compass, insurance companies are favorably disposed toward the use of the Sperry Gyro-Compass, which ultimately will result in a reduction of insurance rates.