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'On The Gun Line' - The R.A.N's Vietnam War In Detail


History Of Naval (Gun Line) Operations In Vietnam


Gun Line - Taking The Weight


Naval operations in the Vietnam War had four major aspects:


(1) Operation Market Time—South Vietnam's 1500 mile long coastline;    

(2) Naval gunfire support of ground forces ashore;

(3) Operation Sea Dragon - The Bombardment of North Vietnamese military targets and the suppression of coastal logistic traffic; and     

(4) Riverine operations in the Mekong Delta and northern Military Region 1.  


RAN warships provided naval gunfire support from March 1967 to September 1971, and participated in Operation Sea Dragon from April 67 until Sea Dragon was suspended in November 1968.




Clearance Diving Team 3 became a unit of the harbour defence element of Operation Market Time while both CDT3 and RANHFV assisted with riverine operations in the Mekong Delta. 


The involvement of the United States Navy in the Vietnam war began in 1950 with the establishment of a naval section of the US Military Assistance Group, Indo-China. The naval advisers assisted French authorities in carrying out coastal and riverine operations against the Viet Minh.   Following the French defeat at Dien Bien Phu, the Geneva cease-fire agreement of 1954 led to the of speedy withdrawal of French naval units, and French personnel left it to the fledgling Vietnamese Navy, a small service, which had been formed in the same year. After the French withdrawal, US Navy advisers assisted in the growth of the Vietnamese Navy, and in late 1961 US Navy minesweepers first assisted VNN ships to carry out patrols near the De-militarised Zone.


In April 1966, the US Naval Advisory Group was made an operational command under the overall US Navy in Vietnam authority of the Commander US Military Assistance Command, Vietnam (MACV). It was designated the Naval Force, Vietnam, and its commander (COMNAVFORV) took responsibility for the United States naval effort in Vietnam, both operational and advisory. Sea Dragon and naval gunfire support operations remained the responsibility of the Commander, US Seventh Fleet.


Tonkin Gulf Incident


Routine naval patrols had been maintained in international waters in the Tonkin Gulf for some time before the destroyer USS Maddox was attacked by North Vietnamese torpedo boats about twenty-eight miles off the coast of North Vietnam on 2 August 1964. A second engagement with North Vietnamese torpedo boats occurred the next day, again on the high seas, but some sixty miles from the North Vietnamese coast.


Retaliatory air strikes were authorised, and on 5 August 1964 strike aircraft were launched from the Seventh Fleet carriers USS Constellation and USS Ticonderoga. This air strike severely damaged the North Vietnamese torpedo boat fleet and petroleum storage areas at Vinh.


These retaliatory air strikes against North Vietnamese military targets continued until late February 1965, when it was decided to respond to increasing numbers of Viet Cong attacks on United States and South Vietnamese installations by stepping up the intensity of air strikes on North Vietnam: air strikes which would not necessarily be restricted to retaliation for specific enemy attacks in South Vietnam.


In March 1965, the South Vietnamese Air Force, the 7th Air Force (i.e. the US Air Force in Vietnam) and aircraft from Seventh Fleet carriers stationed in the Tonkin Gulf began Rolling Thunder, the air campaign against North Vietnam.


Operation Sea Dragon


There were three main routes for the movement of personnel and supplies from North to South Vietnam. The first, a complex of roads and tracks known as the Ho Chi Minh Trail, led from North Vietnam through eastern Laos and Cambodia into South Vietnam's northern and central provinces. A second route used the roads and rivers of the North Vietnamese coastal plain south of the Red River Delta as a logistic feeder system for the Ho Chi Minh Trail, and a third route made use of the coastal waters of the Tonkin Gulf. To augment the Rolling Thunder aerial strikes on inland targets, the Commander Seventh Fleet was authorised to conduct surface ship operations in North Vietnamese coastal waters. Counter battery fire against coastal artillery was permitted only in self-defence and North Vietnamese fishing craft were to be immune from attack. These surface operations—known as Operation Sea Dragon—began on 25 October 1966 when two USN destroyers were ordered to patrol the coastline of North Vietnam and attack vessels carrying arms and supplies to enemy forces in the south.


In the early months of Sea Dragon, operations were limited to a zone between the DMZ and 17°30' north, the latitude of Dong Hoi. Naval bombardment of targets in the DMZ south of the Demarcation Line had been authorised in July 1965.


In late February 1967, the Sea Dragon area of operations was extended to 200 north, near the provincial town of Thanh Hoa; the bombardment of military and logistic targets was approved; and in March the Sea Dragon force was increased from two destroyers to a cruiser and four destroyers.


This task group (Task Group 77.1) of the Seventh Fleet Cruiser-Destroyer Force continuously patrolled the North Vietnamese coast from the southern Red River Delta to the DMZ. The task group contained two task units, 77.l .1 which operated in the northern sector of the Sea Dragon zone, and 77.1.2 operating in the southern sector. Each task unit usually consisted of two destroyers, with one task unit having the cruiser.


The task unit commander was responsible for the planning and conduct of operations within the sector assigned to the unit, and on several occasions this position was given to a RAN destroyer captain. In October 1968, a battleship, the USS New Jersey, joined the task group, HMAS Hobart, in her first Vietnam deployment, joined the Sea Dragon task group in April 1967.


The primary mission of Sea Dragon forces was the interception and destruction of waterborne logistic craft (WBLC)* which ranged in size from small sampans to large steel-hulled self-propelled barges. WBLC traffic was dense in the early months of Sea Dragon, with an average of fifty WBLCs sighted in a day, but very few were detected in the last months of 1968.


The temporary absence of Sea Dragon ships in a truce period brought WBLCs to sea in large numbers, more than 1300 were sighted in the six days of the 1967 Lunar New Year truce. With the disruption of WBLC traffic, the roads and rivers of North Vietnam's southern coastal fringe were increasingly used to move supplies south and it was a logical - step to extend the scope of Sea Dragon to include the bombardment of inland military and logistic targets.


Since bridges were quickly destroyed, the flow of supplies to the South relied more heavily on river ferries and associated supply dumps. Sections of road and ferries vulnerable to bombardment from the sea were known as 'choke points' or 'interdiction points'. Their destruction quickly dislocated the movement of road convoys or the transhipment of supplies from trucks to sampans. Choke points and supply dumps (food, ammunition and fuel) together with beached sampans were the most worthwhile shore targets.


The bombardment of North Vietnam was not without opposition. The ships came under fire from numerous mobile and well-camouflaged batteries of coast defence artillery, while surface to air missiles (SAM) and anti-aircraft guns were used to attack spotting aircraft. The patrolling ships were continuously under surveillance by enemy radar.


In April 1968, Sea Dragon patrols were withdrawn to 19° North and they were suspended on November 1, 1968 by the order of President Johnson during HMAS Perth's second deployment.


Operation Market Time


United States coastal surveillance operations Vietnam began in March 1965 as a result o 'Vung Ro incident' on February 16, of that when a trawler was caught landing arms ammunition at Vung Ro Bay, northern Khanh Hoa province.


The 'Vung Ro incident' provided the first evidence of what had been suspected for some namely, that large quantities of arms and supplies were being brought into South Vie from the sea.


Aerial surveillance flights were started in March, with the first US Navy destroyers 1 assigned to coastal surveillance in mid-March.


Given the code name Operation Market Time, the coastal surveillance operations were under the operational control of COMSEVENTHFLT until August 1965, when Task Force 115, the coastal surveillance force, was formally established with the Chief of the US Naval Advisory Group as task force commander.


Market Time quickly became a joint VNNUS Navy operation. VNN patrol craft joined the US Navy destroyers, the VNN coastal force comprised of armed junks and sampans was modernised, and its inshore surveillance role absorbed into Market Time. Joint VNN-US Navy coastal surveillance centres were established at five Vietnamese ports on the South China Sea and Gulf of Thailand.


United States Coastguard patrol boats and high-endurance cutters also joined the Market Time force while US Navy Neptune and Orion aircraft maintained long-range air patrols, directing the surface ships to any suspicious craft.


The RAN destroyers were never formally assigned to Operation Market Time, but, cruising in the same waters on their naval gunfire support mission, they were often called on to assist Market Time patrol craft by tracking suspicious sampans and, in Military Region 4, supported Market Time raids into the U Minh area.


Clearance Diving Team 3 was an element of the Market Time Harbour Defence Group which protected the principal anchorages of South Vietnam.


Riverine Operations


The first objective of riverine operations in the Mekong Delta was to suppress Viet Cong use of the waterways by maintaining patrols on the Delta rivers and canals.


The second task, arising from this patrolling activity, was the mounting of attacks on enemy positions which were readily accessible by water. To accomplish this second objective, river assault groups in a 'mobile riverine force' were formed, in which river assault craft carried US Army and ARVN infantry units into the heart of enemy-infiltrated territory.


The mobile riverine force used a variety of craft ranging from light river patrol boats equipped with machine guns to sixty-foot armoured monitors carrying a 105 mm howitzer.


A third objective of riverine operations was to block enemy infiltration from Cambodia into Military Regions 3 and 4, by carrying out regular patrols along the waterways near the Cambodian border from the Gulf of Thailand to Tay Ninh province. These interdiction patrols were the major part of the Sea Lords operation which complemented Market Time in coastal waters.


In the ACTOV (Accelerated Turnover to Vietnam) program, which began in late 1968, the riverine vessels and shore bases were transferred to the Vietnamese Navy.


RANHFV crews often provided air support for river assault groups, and took part in combined attacks on Viet Cong positions.


Naval Gunfire Support - 'On the Gunline'


The R.A.N's Three DDGs, PERTH, HOBART & BRISBANE at Sea.


The major role of RAN destroyers after November 1968 was naval gunfire support (NGFS) of forces ashore in South Vietnam. Ships assigned to Task Unit 70.8.9. The Naval Gunfire Support Unit were said to be 'on the gunline'.


The four destroyers made available to Task Unit 70.8.9. from the Seventh Fleet Cruiser-Destroyer Force (usually armed with 5-inch 54-calibre guns) continuously patrolled the coast of South Vietnam to provide NGFS at short notice, and could be reinforced by cruisers if greater fire power was considered necessary.


On its NGFS station, the destroyer cruised in a 'racetrack' — a three to six mile long oval course at least 5000 yards from the coast—awaiting a call for fire from an ANGLICO spotter on shore.




The control of naval gunfire in Vietnam was in the hands of the US Marine Corps 1st Air and Naval Gunfire Liaison Company (ANGLICO) which provided shore fire-control parties in all military regions.


Each shore fire-control party consisted of two components: a NGFS liaison team at the army corps, divisional, or brigade headquarters, and several NGFS spot teams in the field.


The naval gunfire liaison officer (NGLO) at a corps headquarters, such as XXIV Corps Headquarters at Da Nang, received from the Seventh Fleet the name of the ship allocated to NGFS in the corps area. The NGLO then directed the ship to report to a given position and instructed the commanding officer to contact the divisional or brigade NGLO.


The divisional NGLO would usually visit the ship giving a briefing on conditions in the NGFS area. Such a briefing included information on concentrations of enemy troops, possible mined waters, the types of ammunition required, the extent of the ground force area of operations, and the location of 'specific fire zones' which were areas declared by the South Vietnamese Government to have no friendly civilian living in them i.e. any movement detected was presumed to be Viet Cong or NVA.


The Spot Team


To be most effective, naval gunfire requires to be observed ('spotted fire') so that quick corrections can be made if rounds are not falling on the target, and spotted fire was the usual form of NGFS.


When the ship arrived at its NGFS station, radio contact was established with the USMC spot team assigned to the ground force. The spotters were usually airborne in a light aircraft but were sometimes on foot with forward elements of the ground force. The ground commander (US Army or ARVN) requested clearance of the general target area from the Vietnamese province chief and informed the spot team of his requirement for NGFS.


The spot team notified the ship of the target description and grid co-ordinates, the type of ammunition required, and nominated the number of guns required to be ready to fire. The ship then fired on the target with the spotter correcting the fall of rounds and directing fire onto new targets, e.g. enemy troops fleeing from bunkers. The  two components: a NGFS liaison team at the army corps, divisional, or brigade headquarters, and several NGFS spot teams in the field.


The naval gunfire liaison officer (NGLO) at a corps headquarters, such as XXIV Corps Headquarters at Da Nang, received from the Seventh Fleet the name of the ship allocated to NGFS in the corps area. The NGLO then directed the ship to report to a given position and instructed the commanding officer to contact the divisional or brigade NGLO.


The divisional NGLO would usually visit the ship giving a briefing on conditions in the NGFS area. Such a briefing included information on concentrations of enemy troops, possible mined waters, the types of ammunition required, the extent of the ground force area of operations, and the location of 'specific fire zones' which were areas declared by the South Vietnamese Government to have no friendly civilian living in them i.e. any movement detected was presumed to be Viet Cong or NVA.


The spot team notified the ship of the target description and grid co-ordinates, the type of ammunition required, and nominated the number of guns required to be ready to fire. The ship then fired on the target with the spotter correcting the fall of rounds and directing fire onto new targets, e.g. enemy troops fleeing from bunkers.


Two types of non-observed fire were also commonly carried out: intelligence targets where the movement of men and vehicles was detected by electronic sensors, and harassment and interdiction.


Harassment and interdiction (H&I) was usually undertaken at night. Both categories of fire required the ship to fire on pre-arranged targets, usually infiltration routes or tracks leading to wild-rice areas. In harassment fire, these trails would be fired on at random times to disrupt enemy movement. By contrast, interdiction required firing at specified times so that friendly patrols were given freedom of movement.


Other types of non-observed fire were preparatory, in which an operational area was bombarded before being entered by the ground force, and illumination, for night operations.


NGFS Procedure


After the call for fire had been received the bombardment procedure in RAN destroyers varied depending upon the type of gunnery and fire-control system in each ship.


The guided-missile destroyers Hobart, Brisbane and Perth, equipped with an American gunnery and fire-control system, used an almost entirely computerised bombardment procedure in common with the US Navy NGFS ships. Generally this procedure involved the use of the Point Oscar method* in which automatic continuous corrections were made by the fire-control system as the ship altered position.


The bombardment procedure carried out in Vendetta, an older ship equipped with a British gunnery and fire-control system, required the navigator and gunnery officer to set up the fire control system for a particular target, continually plot changes in the ship's .position and pass corrections to the fire-control computer.


Point Oscar


In this bombardment procedure, the fire-control radar locked onto a selected reference point which was commonly a geographical feature such as a headland, tower or rock, but also could be a specially-positioned buoy. The ship's position relative to the reference point was ascertained, and the relevant bearing and distance fed into the


*Point Oscar or, point of origin, i.e., a chosen reference point on the bombardment grid used by the ship's gunnery officer.


As the ship proceeded into a firing run, the computer allowed for a number variable factors, e.g. ship movement, wind and tide, and provided a corrected range and bearing from the ship to the reference point thus ensuring that the ship's position was accurately known when a call for fire was received.


The relative position of the target from the reference point was then fed into the computer which solved the triangle by supplying the 'gun target line'— the bearing and range of the target from the ship. The guns were automatically pointed at the target and elevated to the necessary angle for accurate fire.


On receiving a call for fire, the navigating officer fixed the ship's position and measured the range and bearing of the target from a position the ship would reach one to three minutes later. T target range and bearing were then set on t fire-control computer, as the gunnery officer chose which turret was to fire the ranging gun, and ordered the necessary ammunition to be provided.


The computer allowed for variable ballistic facts such as wind, tide, air density, temperature and differing projectiles in calculating the gun target line and gun elevation for the target range.


When the ship arrived at the predetermined navigational position, the computer was switched on and, taking account of the ship's course and speed, continuously computed the gun target line.


As a safety measure, the computer solution was checked in the operations room before reporting 'ready to fire' to the spotter.


The ship was told to open fire by the spotter, who, observing the fall of shot, gave corrections which were applied to the computer until the rounds were on target.


With the target 'found', 'fire for effect' was ordered and the required number of rounds fired in one burst.


This bombardment procedure differed essentially from the Point Oscar method in that the fire-control radar did not fix on a reference point so that the computer could not be set up until the ship's position was fixed and the target range and bearing established.


For Vendetta, each change of target was in effect a new target, requiring new data to be given to the computer, whereas with the Point Oscar method, fresh targets could be engaged quickly as the guided-missile destroyers were able to shift targets rapidly by applying fresh, target bearings from the reference point directly to the computer.


In all ships, the gun crews remained at 'defence stations' as long as the ship was awaiting a call for fire.


To assist the spotter observing fire in rugged country or jungle, smoke projectiles were used for the ranging salvoes. The usual explosive round used was high explosive (HE) fused to burst on impact or explode in the air above the target.


Sea Dragon Procedure


Sea Dragon targets were chosen by the Commander, Seventh Fleet Cruiser-Destroyer Force, after the evaluation of aerial reconnaissance photographs and other intelligence information. The Sea Dragon commander assigned targets to the task units.


Sea Dragon targets fell into three categories:


a. Military targets near populated areas. These could be fired on only when a spotting aircraft was available. Strict controls were maintained on bombardment of these targets to ensure accurate firings on military areas only.


b. Military targets on the coastal logistic routes from North to South, away from civilian areas. These could be engaged without spotting aircraft. WBLCs and truck convoys were in this category;


c. Coastal defence sites which were attacked when ordered, received suppressive fire during the engagement of other targets, or were fired on after engaging Sea Dragon ships (i.e. counterbattery fire).


For attacking shore targets, one of the two task unit ships (usually the destroyer whose guns had the longest range) was designated the primary firing ship. On the run in to the target area, both the primary ship, and the second destroyer—the 'shot gun' destroyer—concentrated their fire on coastal defence sites. When the position for opening fire against the shore target was reached, the 'shot gun' ship continued with suppressive fire against the coastal defence sites while the primary firing ship engaged the allotted target. With the target shoot completed, both ships retired at high speed continuing to fire on the coastal defence sites until out of range.


This procedure was carried out even if the coastal defence sites were not active as it was usual for the artillery batteries to be moved from one site to another in an attempt to deceive the Sea Dragon force. After a rapid shift of guns and ammunition, a coastal defence site classified by naval intelligence as 'unoccupied' could be active twenty-four hours later. For this reason, all sites were treated as active, and fire from them was always expected. Sea Dragon ships were not permitted to remain within range of an active coastal defence site: on coming under fire they were required to leave the area, engaging the enemy with counterbattery fire as they went.


As soon as the ships were outside the range of the coastal artillery, thus regaining the tactical advantage, they were able to bombard the coastal defence sites at maximum range, with spotting aircraft to pinpoint the targets.


As with NGFS, an airborne spotter flew near shore targets to give corrections, but in Sea Dragon the spotting aircraft were generally from Seventh Fleet aircraft carriers. Damage to inland targets was confirmed by aerial reconnaissance. WBLCs were detected and tracked by spotting aircraft, by the ship's radar and, on occasions, visually. The Point Oscar method of bombardment was used whenever possible.


Phantom echoes', giving a strong radar picture and manifesting a definite course and speed, were quite common in the Tonkin Gulf. At night, their true nature was not revealed until after they had been fired on, for although they did not fade from the radar screen, close visual scrutiny revealed nothing in the area. They were thought to be caused by flocks of birds.




Yankee Station

RAN destroyers were sometimes withdrawn from Sea Dragon or NGFS to join the destroyer screens of Seventh Fleet attack carrier striking force task groups on Yankee Station in the Tonkin Gulf between Hainan and North Vietnam. The destroyers provided an anti-submarine and antiaircraft escort for the carriers, and were also detailed to rescue aircrew forced to eject or ditch as a result of combat damage or carrier operations misadventure.


Logistic Support


The RAN ships were supplied with fuel, ammunition, food and other stores by the ships of the Seventh Fleet Mobile Logistic Support Force, ranging in size from the 53,000 ton USS Sacramento (AOE-1) able to replenish a destroyer with fuel oil, ammunition, food and stores simultaneously, to smaller oilers, ammunition ships and store ships.


With their US Navy-type armament and fire control system, Hobart, Perth and Brisbane, modified Charles F. Adams class destroyers built in the United States, were well suited to integration with the Seventh Fleet. Minimal modification of logistic procedures was required as the ships used standard USN ammunition, electronic components and other spare parts.


Vendetta, with her British armament, was not so well placed, and the ammunition for her 4.5" guns was taken from Australia to Subic Bay by HMAS Jeparit. At Subic Bay, it was transferred to US Navy ammunition ships for delivery to Vendetta on the gunline. Prior to shipment from Australia, the shells for Vendetta were packed in US Navy-type pallets for easy stowage in the ammunition ships but the cartridges, being of a different type from those used by the other destroyers, were brought in Australian containers.


Modified 'housefall' kingposts (a type o stanchion used for the delivery of stores) we installed fore and aft in Vendetta to ensure compatibility with the US Navy replenishment ship; and four probe fuelling points were fitted to provide rapid refuelling.


The destroyers were replenished in two ways. an underway replenishment (UNREP), the destroyer steamed alongside the supply ship, lines were passed between the ships, and fuel oil an supplies transferred while the ships kept parallell courses. Supplies transferred by helicopter co prised a vertical replenishment (VERTREP).


If a supply ship carried a helicopter, both types of replenishment went on together. A typical replenishment from Sacramento could find fuel oil being supplied by two rigs, food and ammunition by a third rig, while the VERTREP helicopter delivered further stores, ammunition, mail and personnel.


The destroyer returned empty brass cartridge cases.


In the Tonkin Gulf, a 'heavy' UNREP could take up to four hours with 'clear lower deck' any time of the day or night bringing all sailors not actually on duty to the upper decks to assist with the clearing of the fast-arriving food and ammunition.


If the UNREP was solely for fuel oil, only a few sailors were needed to connect the oil rigs.


The destroyers were replenished with ammunition and fuel about every three days while food stores were supplied about every seven days. Mail was brought either by logistic support ships from Subic Bay or delivered by helicopter from the carrier group.


Some idea of the magnitude of the logistic task can be gained by considering the following figures for HMAS Brisbane's last deployment in which the ship steamed 27,000 miles using 11,000 tons of fuel oil. In 85 days 'on the gunline', she fired 7760 rounds at 798 targets. Her ship's company of 350 consumed 26,000 lb of flour, 13,700 lb of sugar, 51,240 lb of meat, 28,000 lb of potatoes, 25,058 lb of fresh vegetables and 7500 lb of quick frozen vegetables. They spread the contents of 2007 bottles of tomato sauce on their meals and washed the food down with 1000 gallons of milk and 74,750 bottles of soft drink. For dessert they ate 32,000 lb of fruit and 2928 gallons of ice cream. $18,020 was spent at the ship's canteen and 1800 lb of soap powder, 450 lb of starch and 180 lb of bleach were used to wash the 270,000 lb of laundry.


Including the Vietnam War, RAN warships have seen active service in four wars since World War II. In two of these, the Malayan Emergency (June 1948 to July 1960) and Confrontation with Indonesia (September 1963 to August 1966), the RAN ships worked exclusively with other Commonwealth navies. By contrast, the naval forces engaged in the Korean War (June 1950 to July 1953) were multinational in composition but under overall US Navy command; and, as related earlier in this section, the RAN destroyers in Vietnam were operationally and logistically fully integrated with the US Seventh Fleet.


NGFS Call Signs for Australian Gun Line Destroyers.  - HMAS Hobart  'Royal Purple’  -   HMAS Perth 'Gunpowder’  -  HMAS Brisbane ‘Flamboyant’  -  HMAS Vendetta - ‘Premier’




                                                Miles Steamed     Rounds Fired        Replenishments at sea      Number of times enemy fire received



HMAS HOBART                  


1st Deployment                                    52529                             9204                             117                                                     9


2nd Deployment                                  44579                             16270                            95                                                       3


3rd Deployment                                   43915                              16901                           75                                                        -


Totals                                                     141023                             42475                         287                                                      12





1st Deployment                                    64750                                13351                         104                                                      4


2nd Deployment                                   44820                                7648                             70                                                      1


3rd Deployment                                     39857                                9712                            43                                                       -


Totals                                                       149427                              30711                         217                                                    5



HMAS BRISBANE                      



1st Deployment                                      40465                                   7891                          56                                                      -


2nd Deployment                                     27011                                   7760                          48                                                      -



Totals                                                        67476                                   15651                        104                                                   -      




HMAS VENDETTA                               39558                                     13709+                       47                                                    -


+4.5"    *40mm



All Ships Grand Total                          397484                                   102546                        655                                                17



*Pronounced 'wiblik'