The HMB Mine. The HMB had no magnets and was not intended to adhere to the bottom of the target ship. On the contrary, it was designed to laying beneath a specific target ship or in other chosen areas as a ground influence mine. Its characteristics are as follows: (Specifications are approximate.)

Description

Case material

KSS

Length of case

56 in.

Diameter of case

45 in.

Weight of charge

1750 lb.

Maximum depths

80-115 ft., depending on the influence unit used

Method of firng

MA 2, MA 3, and DM 1

Figure 116 – HMB Mine