INTELLIGENCE MEMORANDUM POSSIBLE ALTERNATIVES TO THE ROLLING THUNDER PROGRAM (THE CASE IN WHICH THE SEA DRAGON PROGRAM IS EXTENDED

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP80T01629R000300080002-2
• Release Decision: RIPPUB
• Original Classification: T
• Document Page Count: 13
• Document Creation Date: December 21, 2016
• Sequence Number: 2
• Publication Date: July 5, 1968
• Content Type: IM

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Top Secret
DIRECTORATE OF
INTELLIGENCE
NAVY review
completed.
Intelligence Memorandum
POSSIBLE ALTERNATIVES TO THE ROLLING THUNDER PROGRAM
(The case in which the Sea Dragon Program is
extended north to the Chinese Buffer Zone) (No. 5)
Top Secret 25X1
5 July 1968
Copy No. 10
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CENTRAL INTELLIGENCE AGENCY
Directorate of Intelligence
5 July 1968
Possible Alternatives
to the Rolling Thunder Program
(The case in which the Sea Dragon Program
is Extended North to the Chinese Buffer Zone)
(No. 5)
S ummary
This memorandum analyzes the estimated effects
of an extension of the Sea Dragon Program north to
the Chinese Buffer Zone but under the target restric-
tions existing before 31 March. The analysis is
based on the assumption of a campaign against North
Vietnam's heartland by a force as large as three
cruisers, 22 destroyers, and the recently reactivated
battleship New Jersey, but subject to the same tar-
geting restrictions that applied to air attacks prior
to the March 1968 standdown.
An extension of the Sea Dragon Program would
add little to what has already been achieved by
previous air and naval attacks on North Vietnam.
Only a few significant military or economic targets
are within the 8 to 10 mile coastal strip that could
be subject to effective naval gunfire. All of these
targets could be attacked with equal or greater effec-
tiveness by aircraft.
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The indirect effects of an expanded Sea Dragon
Program might have a greater impact than the
physical. attack on inland targets. The major
indirect effect would be the psychological impact
of the visible presence of Allied warships. As an
indication of Hanoi's inability to provide security,
this presence might depress the morale of the North
Vietnamese. Disruptions of fishing and agriculture
along the coast could easily be made good by
increased imports.
The nominal benefits, particularly the psycho-
logical impact, that might accrue to an extended
Sea Dragon Program could be more than offset if
North Vietnamese countermeasures resulted in the
loss of a major Allied warship. North Vietnam's
present conventional coast defense -- eight light
bombers, 14 torpedo boats, and numerous coast
artillery weapons -- could not deter a forcefully
prosecuted Sea Dragon effort and would probably be
hard pressed to sink or severely damage US ships.
The risk of loss could be substantially higher if
North Vietnam and its allies felt that the escala-
tion represented by the northward extension of the
Sea Dragon Program justified the introduction of
Styx or Samlet surface-to-surface missiles.
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I. Previous Sea Dragon Operations
Operation Sea Dragon, a US Navy surveillance
and interdiction operation conducted by surface
ships against the coast and offshore water traffic
of North Vietnam, has been limited to the southern
Panhandle of North Vietnam. The operation was
first authorized against offshore watercraft between
17? (the DMZ) and 17?-30' North latitude in October
1966. In February 1967, it was expanded to include
shore bombardment of military-associated targets
and to extend the range of the attacks to the 20th
Parallel. The operation has been restricted since
March 31 to those areas of North Vietnam south of
the 19th Parallel.
The Sea Dragon force has been small, with only
one cruiser and four destroyers normally on station
off the coast of North Vietnam. At least one of
these ships has always been equipped with surface-
to-air missiles. Australian and New Zealand ships
have frequently participated. Spotter aircraft
have usually been available for target identifica-
tion and fire adjustment in good weather, and, on
occasion, US aircraft have conducted coordinated
attacks with Sea Dragon ships.
Sea Dragon forces have attacked watercraft,
vehicles, roads, railroads, bridges, coast artillery,
radar and antiaircraft sites, supply depots, bar-
racks, and electric powerplants. The attacks have
been difficult to evaluate because strikes have
often been at night, in bad weather, without spotter
aircraft, or against targets that have been attacked
by aircraft. Secondary explosions have often been
observed, however, and watercraft sightings which
averaged 30 per day at the start of the program
have dropped to less than four per day.
Sea Dragon forces have sustained minor ship
damage and several casualties from North Vietnamese
shore battery fire. Twenty Allied ships have been
struck by small-caliber shells through December
1967. Five crewmen have been killed and 18 wounded.
North Vietnam's small air force and navy have not
attempted to attack Sea Dragon ships, probably be-
cause North Vietnamese air and naval bases have been
located too far north for effective opposition.
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II. Expanded Operations
The nature of an expanded Sea Dragon Program
above the 20th Parallel is not known.
that We assume
the restricted bombing areas existing under
the March ground rules would continue. In addition,
the program would be subject to the following con-
siderations. A maximum of one battleship, three
cruisers , and 22 destroyers could be sustained on
station off North Vietnam without recourse to
further ship reactivation. The New Jersey can be
available for use against North Vietnam in October
1968. These ships would probably stage hit-and-
run attacks rather than maintain a constant patrol
in fixed locations that would invite North Vietna-
mese counterattacks. Sea Dragon attacks would be
limited generally to targets within 17,000 yards.
This limitation is determined by the offshore water
depths and ship drafts, as shown in the following
tabulation:
Ship Type
Destroyer Cruiser Battleship
Main armament 5-inch
8-inch 16-inch
Range (yards)
Maximum 18,000 29,000 42,000
Effective range a/ 15,000
26,000 32,000
Ship draft (feet) 18 27 38
Ave rage req ui re d
offshore distance
(yards)
Average effective
range a/ inland
(yards)
10,000 12,000 15,000
5,000
14,000
17,000
a. The longest .range at which
gunfire can be ac_
curateZy controlled. Technical standards for deter-
mining this range vary with individual classes of
weapons,
All of the areas capable of being struck by an
expanded Sea Dragon force could also be hit by air-
strikes, and in some respects there would be little
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to choose between the two modes of attack. Ships
would remain on station for longer periods of time,
firing continuously; but air ordnance would be
heavier than conventional shells, as shown in the
following tabulation:
Explosive Weight a/
Ship
Ordnance (pounds)
Destroyer
5-inch
shell
7.2
Cruiser
8-inch
shell
21
Battleship
16-inch
shell
154
750-pound
bomb
386
a. The effectiveness of a bomb or projectile varies
as the one-third power of the weight of explosive.
Naval gunfire would be delivered more accurately at
short ranges and under conditions of adverse weather
and visibility, but air attacks would probably be
delivered with greater accuracy in good weather be-
cause of the extremely long gun ranges required by
sea forces to strike targets in the north. Air-
craft losses north of the 20th Parallel in the
heavily protected Delta area of North Vietnam would
be high, but the loss of a major warship would have
a tremendous psychological impact.
III. Targets
Few military targets of any significance would
be within effective gunfire under an expanded Sea
Dragon Program, except for air defense sites east of
Haiphong. Naval craft and bases in the Cat Ba
Island area are within range of effective naval gun-
fire, but these targets are well protected by water-
level caves. A few small barracks and storage areas
could be attacked, but these facilities could be
easily dispersed with little disruption to military
operations. The airfield at Cat Bi, east of Haiphong,
would be within range, but this field has been infre-
quently used. East of Haiphong, some air defense
sites, including three to six known SA-2 sites,
could be reached by naval gunfire. The neutralization
of these sites and the relocation inland of coastal
SA-2 battalions, radars, and antiaircraft artillery
weapons could conceivably open a less hazardous
avenue of approach for US aircraft attacking Haiphong
from seaward.
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Few economic targets of any significance would
be within effective gun range. All rail lines,
major high-ways, and bridges are well inland, beyond
the effective range of the largest naval guns
available to Sea Dragon forces. Even offshore
watercraft would be relatively immune. Those craft
using coastal routes south of Haiphong could easily
be diverted to operating exclusively on the inland
waterway network, well out of range of naval guns.
Those operating north of Haiphong between Haiphong,
Hon Gai, and Cam Pha are well protected by numerous
offshore islands. There are no major industrial
facilities within effective gun range and few
storage sites. Twenty-two small dispersed petro-
leum storage tank sites with a capacity of approxi-
mately 3,000 metric tons, about 3 percent of the
total storage capacity of North Vietnam, are with-
in range, but these sites would be difficult to
destroy. The tanks are dispersed within the sites,
are buried in excavations, and are hardened with
earth covering.
Other military and economic targets in Haiphong,
Hon Gai, and Cam Pha could conceivably come under
attack by Sea Dragon forces, but attacks on these
ports would be highly inaccurate because of the
great ranges involved. Moreover, they would risk
heavy civilian casualties and damage to foreign
shipping. The New Jersey could deliver a 16-inch
projectile 42,000 yards, and the ranges to these
targets from likely offshore firing sites would be
between 32,000 and 42,000 yards. The average fir-
ing error at these long ranges, however, could be
as great as half a mile. Maximum effective range
for the New Jersey -- the range at which gunfire
could be delivered accurately -- is only 32,000
yards. Furthermore, shore bombardment is most
accurate when ships operate at firing ranges of
only a few thousand yards, at slow speeds, and near
familiar terrain -- conditions not likely to be met
near these cities. Attempts to close the range,
reduce speed, or remain in firing areas for lengthy
periods of time for familiarization would greatly
increase the risk of grounding or North Vietnamese
countermeasures. The waters off the coast of these
targets are shallow, poorly charted, and near the
sites of North Vietnam's strongest coastal defenses.
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IV. Indirect Effects
Fishing would be adversely affected, but even
large losses would have little effect on the North
Vietnamese economy. North Vietnam's major fishing
centers are located north of the 20th Parallel at
Mon Cay near the Chinese border, Haiphong, Do Son,
and Cat Ba Island, and these centers would undoubtedly
be harassed by warships conducting shore bombardment
or searching for naval and logistics craft. Deep-sea
fishing, however, is as yet relatively undeveloped
in North Vietnam. The total annual fish catch before
the bombing for all of North Vietnam was only about
200,000 tons, of which about 110,000 tons was salt
water fish and the remainder fresh water fish raised
in the many ponds and irrigated fields in North
Vietnam. Most of the catch is intended for local
consumption because of the lack of refrigeration
facilities. In addition, deep sea fishing in the area
north of the 20th Parallel has already been adversely
affected by offshore air attacks against suspected
logistics or naval craft.
Agricultural production could drop slightly as
a result of the abandonment of farm land close to
military, logistic, and economic targets. A small
part of the cultivated area of North Vietnam could
be subjected to naval bombardment north of the 20th
Parallel, and some of this would be the highest
yielding land in North Vietnam.
Manpower requirements to support the war could
increase slightly, and fewer troops might be avail-
able to fight in the south. Extended Sea Dragon
operations would probably result in the increased
diversion of manpower to coastal areas to serve as
spotters, coast artillery gunners, and in other
coastal defense forces. The number diverted should
be only a tiny fraction of the total number of
workers so far diverted to war-related activities.
The necessary additional manpower probably could be
made up of farm workers who abandon farming opera-
tions because of the shelling. The presence of
enemy warships off the coast of North Vietnam's
heartland, however, would enhance North Vietnam's
invasion fears and might serve to freeze additional
military manpower in the north that might otherwise
be sent south.
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International shipping might be disrupted, but
such disruption would almost certainly be minimal.
Foreign-flag ships regularly transit the Tonkin
Gulf to and from Haiphong, Hon Gai, and Cam Pha.
US warships engaged in shore bombardment
off these ports or in close proximity to interna-
tional shipping lanes could conceivably help to
discourage these ships from calling at North Vietna-
mese ports. Intimidation of these ships, however,
would not likely enhance the effect already achieved
by air attacks on Haiphong, Hon Gai, and Cam Pha
and by US air and naval forces operating in the
lower end of the Gulf.
Morale of the North Vietnamese population and
leaders would undoubtedly be affected by the visible
presence of naval warships off the densely populated
areas of North Vietnam north of the 20th Parallel.
The psychological impact of naval gunfire on civilian
and military personnel far exceeds that of air
attacks, according to survivors of both types of
attacks. However, in view of the demonstrated
resiliency both to air attacks and to naval bombard-
ment south of the 20th Parallel, it is doubtful that
North Vietnam's will to persist will diminish under
an extended Sea Dragon Program.
V. Countermeasures
The North Vietnamese might be able to sink or
severely damage one or more Allied warships partici-
pating in an expanded Sea Dragon operation with the
means currently at their disposal, although such
losses would probably not prevent Sea Dragon forces
from carrying out their missions. A small bomber
force -- eight IL-28 light bombers -- could be used
against naval ships, and MIG aircraft have been
noted conducting exercises over the Gulf of Tonkin.
A force of about 14 modern, fast torpedo boats, in-
cluding a new, Chinese-built hydrofoil boat, is
based in the Haiphong - Cat Ba Island area and could
operate against inshore Allied naval forces with a
minimum exposure to early detection. Thirty-seven
coastal defense sites, the strongest such sites in
North Vietnam, are located north of the 20th Parallel,
most of them guarding the sea approaches to Haiphong
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on the Do Son Peninsula and off-lying islands, and
nine of them make use of caves. The artillery at
these sites are mostly 100-mm and 120-mm field guns
with ranges around 20,000 meters, but rweaappoon?uas
large as 152-mm and 130-mm guns
to 27,000 meters have been identified. SA-2 bat-
talions could also attempt attacks on Sea Dragon
ships with their missiles in surface-to-surface
mode -- missile range in this mode is approximately
16 nautical miles. SA-2 attacks would probably be
ineffective, however, because of the small fragmen-
tation warheads and probable accuracy limitations.
Furthermore, SA-2 battalions would probably not be
moved from their air defense sites to combat sur-
face ships, because Sea Dragon attacks would almost
certainly be accompanied by a resumption of air
attacks. Mines and frogmen might also be employed,
should US warships attempt to penetrate shallow
waters at slow speeds in an attempt to improve the
accuracy of their fire.
The expansion of Sea Dragon operations, and
particularly the employment of the New Jersey,
might be viewed by North Vietnam and its allies as
a significant escalation of the war and might serve
to justify the introduction of surface-to-surface
missiles and other new weapons systems. Both the
Samlet and Styx anti-ship missiles could be deployed.
in North Vietnam. The Samlet can carry a one-ton
warhead to a fuel-limited range of perhaps 70 nau-
tical miles, and the Styx can carry a warhead
weighing more than 800 pounds to about 25 nautical
miles. The operational range of both, missiles,
however, is believed to be limited to the radar
horizon of the launch unit. Either missile could
be fired from ashore, but, because most of North
Vietnam's coast is very low, effective ranges might
not exceed the 10 to 15 nautical mile range of con-
ventional coastal artillery. Styx in a ship-to-
ship role mounted on North Vietnamese torpedo boats
would provide a more serious threat.
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Top Secret
Top Secret
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