a. General

The Siebel ferry is actually an Army landing craft, or "invasion barge," of the type that was mentioned frequently at the time when a German seaborne attack upon Great Britain appeared probable. It is discussed here because a large number of them, heavily armed and apparently under control of the German Navy, are operating in western European coastal waters to supplement port and coastal batteries. (See fig. 1.)

The Siebel ferry is conspicuous because of its hull, which consists of a pair of steel sectional pontons, each of which is made up of nine lightly constructed sections and one larger stern section. There is a 20-foot space between the two pontons, which are equipped with wooden runners to facilitate landings and to protect the craft against damage. The craft is powered by two engines—perhaps airplane engines, installed in the stern section of each ponton, which drive underwater propellers. In some cases these engines may be supplemented by air propellers so that the craft can operate in shallow waters where underwater propellers would foul. The Siebel ferry has a speed of 8 to 9 knots, and it is believed to be highly maneuverable and fairly seaworthy. Its shallow draft reduces its vulnerability in minefields.

Figure 1.—Sketch of Siebel ferry (based on a photograph).

The heavy type described in the next paragraph is 75 feet long and 56 feet wide, but there is no information available to show how the three known types differ as to size and construction features. (See fig. 2.)

b. Types

The three known types of this vessel are as follows: The heavy (Kampffähre), the light, and the transport (Trossfähre) type. The heavy and light types are heavily armed and are notable, from the point of view of landing troops, for three features:

(1) They are fully mobile offshore and therefore are not good counterbattery targets.

(2) They cannot be plotted like normal coast defenses.

(3) They might be very effective against landing craft and assault landing troops.

The heavy type usually carries three 88-mm dual-purpose guns, and two 37-mm or two 20-mm antiaircraft machine guns, and one 4-meter-base stereoscopic range-finder with predictor. (Fig. 2(2) shows the layout of guns.)

The armament of the light type consists of four 37-mm or four 20-mm guns, one in each of the four corners of the deck, and possibly a fifth gun in the center. The 20-mm guns may be of the four-barreled type.

The transport type has only open deck space and is designed for transportation of personnel, supplies, and vehicles, and for ship-to-shore lighterage. Its armament usually consists only of one antiaircraft machine gun.

Figure 2.—Plan of Siebel ferry.