Anti Submarine Warfare In Inshore Waters (Part 3)

ASW action by ships

1.  Possibly relying on the prevalence of non-submarine contacts and poor sonar conditions in inshore waters, a submarine may refrain from offensive action until fairly certain that it has been detected and classified. A deceptive use the ship’s sonar intended to disguise the act that the contact is held should be considered.The streaming of decoys under these circumstances will immediately reveal that contact is held.

2.  Once ships are within about a mile, the submarine is even more likely to take offensive action than it would in deep water since it has less chance of evasion in shallow waters.

3.   High reverberation levels may increase secondary mutual interference, and it may be better to use only one ship to attack, with the others standing off in support. They must, however, keep close enough to be a matter of immediate concern to the submarine.

Convoy formation

While convoys should cruise on a broad front for the best ASW defense, this is unlikely to be practicable in inshore operations. The following factors will affect convoy formation and spacing:

1.            Geographic considerations.

2.            The mine risk, which necessities the use of searched channels.

3.            The nuclear threat.

4.            The threat from conventional air attack, missile firing fast patrol boats, and so forth.

5.            Convoy organization to expedite the joining or leaving of the various sections of the convoy.

In many inshore waters, the width of searched channels will restrict convoys of searched channels will restrict convoys to formations o not more than one or two columns. This will result in long un-maneuverable columns and in an increased tendency to straggle.

Convoy surface screen

It is likely that open ocean screening tasks will require the majority of modern fast ASW ships, leaving the inshore task o the smaller and slower ships.

When there is a grave shortage of ASW ships, it is probably better to work them in pairs, even at the expense of occasional unprotected convoys. Such unprotected convoys should always be provided with an administrative escort.

In addition to any inshore escorts that can be provided, sections of ocean convoys passing inshore will probably be accompanied by elements of their ocean screen, and ASW support groups may be detailed to augment the defense through areas of submarine probability. Consequently, the strength and composition of the surface screen may change frequently, and command relationships and the organization of the screen may have to be changed accordingly. In view of this, orders concerning the escort and support of convoys should always include clear instructions concerning command relationship between forces. A senior OTC of an ASW support group, which provides support to an escorted convoy may take over tactical command. (ATP 1A)

When operating in areas where the ASW support group is normally deployed, his local knowledge will often make this desirable. In most other cases, the OTC of the through escort should retain tactical command and frequent changes in command should be avoided.

Convoy administrative escorts

Any convoy for which no other surface escort is available should be given an administrative escort whose duties will include:

1.            Control of the convoy, in cooperation with the commodore.

2.            Leading the convoy through searched channels.

3.            Providing a communication link between the convoy and the OCA.

4.            Acting as reporting ship in the case of enemy attack.

Local knowledge of pilotage conditions, minesweeping state, and so forth, and at least a limited ASW counterattack capability are most desirable in this escort.

Execution of “wreck check” in coastal waters

1.            The purpose of executing a wreck check is to find out quickly if sonar contacts obtained in coastal waters coincide with the positions of known wrecks. This improves the process of classification of sonar contacts.

2.            A wreck check procedure should be executed approximately every 6 minutes.

3.            In order to carry out the procedure, we require:

a.            A wreck chart of the particular area of operation.

b.            A plastic disc.

4.            The procedure is executed as follows:

a              Determine the position of the ship and mark this on the wreck chart.

b             Mark the time the position was obtained on the plotting table.

c              Place the center point o the wreck disc over the position on the wreck chart and copy all wrecks within a 5-mile range.

d             Place the disc center point over the previously marked position on the plotting table and copy all wrecks on the plotting table.

5.            Since the plotting table does not take into tidal stream/currents account, all previously plotted wreck positions must be erased each time.