Sprengboje C and Sprengboje D. These are moored, conical floats used as sweep obstructors, laid by surface craft. They are defensive, anti-sweep devices laid in and moored-mine fields. The maximum length of their mooring cables is 360 feet.

Figure 124 – Sprengboje C

Decription of Case

Shape

Conical upper section welded to hemispherical lower section

Material

Steel

Diameter

15 in.

Length

37 in.

Charge

1 lb. 13 oz.

Total weight in air

50 lb. (approx.)

Decription of External Fittings

Lifting eye

At top of conical section

Securing lugs

Two, 180° apart on lower hemisphere

Soluble plug fitting

Threaded into side of flange on lower hemisphere

Firing assembly

In pocket in base, secured by vertical rod and nut at top of float. Firing sleeve contains hole for safety pin.

Figure 125 – Sprengboje D

Type D differs from Type C as follows:

1. The base of the float contains no soluble plug fitting on the flange.

2. The arming hydrostat locks in the armed position.

The only self-disarming feature is a device which locks the firing pin when the float surfaces. This is extremely unrealiable.