by R.A. Gregory

The Liesure Hour (1898/9)

I apologise for the quality of the illustrations. The book was in a very bad condition and this was the best I could do.

The GymnoteThe recent performance of the submarine boat the Gustave Zédé at Toulon, in the presence of M.Lockroy, have given more satisfaction to our French neighbours than to our own naval engineers. The value of this type of boat has probably been over-estimated; nevertheless, the possibilities of submarine fighting have been indicated and the results of the manoeuvres will have to be taken into account. Nothing is known of the details of construction of the Gustave Zédé since these are kept a close secret, but a few particulars referring to it and an earlier submarine boat, the Gymnote are given in the French scientific periodical "La Nature," from which the accompanying illustrations have been reproduced. The Gymnote, which was put on its trial ten years ago, was practically a Whitehead torpedo nearly sixty feet long and about six feet across at its widest point. The boat could be made to sink or rise in the water at will, and when submerged could be made to travel at a constant depth below the surface. It was only built to determine the practicability of submarine navigation, and the results obtained with it were so satisfactory that in 1890 a larger boat of the same type was planned and eventually named after the engineer, Gustave Zédé, who designed the original vessel.

The Gustav ZedeThe Zédé is 130 feet in length, and nearly 10 feet in diameter at its widest part. Its maximum velocity is fouteen knots when navigated at the surface and eight or nine when submerged. By means of an arrangement of mirrors and lenses similar to a camera obscura the commander can make observations when the boat itself is a couple of yards below the surface of the water. But this arrangement is not essential, for when the boat is being navigated on the surface the only part visible is the dome about eighteen inches in diameter and the same number of inches high. In warfare the tactics employed would be to take sight of the enemy through this short conning-tower, then sink the boat before guns could be directed to it, travel under water in a straight line for 400 yards or so, and then rise again to make observations. The enemy would thus be approached by a series of journeys under water until the distance for projecting a torpedo was attained.

As the Gustave Zédé is propelled by electricity stored in secondary batteries, it has only a small range of action, and cannot move far out of its port. In submarine boats of the Narval type, eight of which have been provided for in the French budget for the current year, the vessel is propelled at the surface by steam and under water by electricity. It is said that the Narval, which will shortly be completed, will carry enough fuel to steam 252 miles in twenty-four hours at twelve knots, or 624 miles in seventy-eight hours at eight knots. While under water it will do twenty-five miles at eight knots, or seventy miles at five knots. When the Narval is ready, we shall probably hear much more about the efficiency of submarine boats as fighting machines.