EntranceChannel

EntranceChannel


YOKOSUKA

ENTRANCE CHANNEL

See Figure V-2 , Figure V-3 , Figure V-28 , Figure V-29 , and Figure V-30 for sections of charts for the Approach to Tokyo Bay and Yokosuka Harbor .

The direction of buoyage in Japan for lateral marks is that the starboard hand of a channel or fairway is that on the right hand side, and port hand is that on the left side, of a vessel entering from seaward.

When lit, buoys marking the port hand of channels and fairways usually exhibit green flashing or white flashing lights. Buoys marking the starboard hand usually exhibit red flashing lights. Group flashing lights of the appropriate color are often exhibited by the outermost pair of buoys, and by buoys moored at turning points in a channel and at the junction of two channels.

Sagami Nada (Gulf) (35 ° 00'N 139 ° 30'E) is an extensive bay, which, with Tokyo Wan, deeply indents the southeast coast of Honshu . It lies between two peninsulas, the Boso Hanto on the east and the Izu Hanto on the west, with its entrance between their southern extremities, Noshima Saki (Point) and Iro Saki, about 55 nmi west-southwest. O Shima Island lies almost in the middle of the entrance and the channels on either side are wide and deep. A peninsula named Miura Hanto projects from the head of Sagami Nada. That part of the bay to the west of this projection is known as Sagami Wan. Urago Suido (Channel) leads off the east side of Sagami Nada and into Tokyo Wan, passing between the east side of the Miura Hanto and the west side of the Boso Hanto. Uraga Suido extends about 14 nmi northward from a position between Suno Saki on the southeastward and Tsurugi on the northwestward to the narrows between Kannon Saki and Futtsu Saki.

Shima (34 ° 44'N 139 ° 24'E), the largest and northernmost of the Izu Shichito, lies in about the middle of the entrance to Sagami Nada, in a position almost 20 nmi southwest of Suno Saki. The north and east sides of the island are steep and rocky, but the south and west sides have some sandy beaches. Habu Ko, a small landlocked inlet, indents the southeast end of the island. O Shima (Mihara Yama) is volcanic. Its summit is an active volcano that continuously emits smoke. A light is situated at Kazahaya Saki on the north coast. A ramark (radar marker) transmits from this light. The island was reported to be a good radar target from 26 nmi.

A voluntary traffic separation scheme has been established northwest of O Shima. The traffic scheme should be adhered to as far as practicable in the interest of safe navigation.

Suno Saki (34 ° 58'N 139 ° 46'E) rises to an elevation of 35 m and appears from the south or north as a row of small hills. O Yama, the highest hill in the vicinity, lies 1.25 nmi southeast of Suno Saki and is 193 nmi and conical. A lighthouse stands on Suno Saki.

Tokyo Wan (Bay) is an open bay entered between Suno Saki and Ken Saki (Tsurugi Saki), 10.5 nmi north-northwest. It trends in a general north direction for about 14 nmi to the narrows between Futtsu Saki and Kannon Saki. Then it curves northeast for about 25 nmi. The coast immediately adjacent to Tokyo Wan is low, but to the north and northwest are high mountains, which afford some protection against wind from the northwest quadrant. The south portion of the bay is called Uraga Suido. Its middle and north portions are the locales of the major ports of Tokyo , Yokohama , Yokosuka , Tiba Ko (Chiba Ko), and Kisarazu Ko.

Specific landmarks are as follows:

  • Uki Shima ( Island ), a 159-foot islet with steep cliffs, lies about 8.5 nmi north-northeastward of Suno Saki and about 0.5 nmi off the eastern shore of Urago Suido.
  • Nokogiri Yama, about 3.5 nmi north-northeastward of Uki Shima, is 1,079 ft high and appears as an isolated helmet-shaped peak when viewed from the west.

Ships destined for ports within Tokyo Wan area should steer for the Outer Approach Point (35 ° 03.2'N 139 ° 43.5'E), about 5.5 nmi south-southeastward of the light on Tsurugi Saki. Then steer about 023 ° , distance of 7.4 nmi, for the Inner Approach Point (35 ° 10'N 139 ° 47.1'E). Depths in Uraga Suido are variable, but not critical anywhere within the fairway. Several rocky patches, with depths of 5.25 to 9.75 fathoms (9.6 to 17.8 m) lying up to 2.5 nmi east-southeastward of Tsurugi Saki, are the only known off-lying dangers.

Uraga Suido leads off the inner part of Tokyo Wan. From the middle of its entrance between Suno Saki and Ken Saki, it trends in a general north direction for about 14 nmi. Its north limit lies between Kannon Saki on the West and Futtsu Saki, about 4 nmi north-northeast. The depths through Uraga Suido vary from over 656.2 ft (200 m) to 121.4 ft (37 m) in the narrows. In the inner part of the bay depths of more than 121.4 ft (37 m) prevail on the west side for a few nmi, and over the central part the depths range from 27.2 to 108.3 ft (8.3 to 33 m), but depths of less than 27.2 ft (8.3 m) extend for almost 10 nmi from the head.

Ken Saki (35 ° 08'N 139 ° 41'E) is the southeast extremity of Miura Hanto, and is the west entrance point to Uraga Suido. The coastline between Ken Saki and Kannon Saki, 8 nmi north, is indented by Kaneda Wan in the south portion, and by Kurihama and Uraga inlets in the north portion. There are many peaks along the coast as well as continuous stretches of low hills. Except near Kannon Saki, the water along this coast is shallow, and detached rocks and sunken reefs are numerous.

Uraga Ko (35 ° 14'N 139 ° 43'E) is entered about 1.5 nmi southwest of Kannon Saki, and is located close north northeast of Kurihama Wan. It consists of an inner and outer harbor. The inner harbor penetrates about 0.6 nmi and is surrounded by a rim of hills, 164 to 262.5 ft (50 to 80 m) high. Shipways, docks, workshops, and quays of a heavy industries company occupy most of the inner as well as part of the outer harbor.

Kannon Saki (35 ° 15'N 139 ° 45'E) is a steep conspicuous bluff, 236.2 ft (72 m) high, densely covered with trees, which lies 1.5 nmi northeast of Uraga Ko. It lies on the southwest side of Uraga Suido, at the entrance to the inner part of Tokyo Wan. A light is shown from an octagonal concrete tower, 48.9 ft (14.9 m) high, situated on Kannon Saki.

Ships should navigate with extreme caution northward of Kannon Saki in the vicinity of the forts. The numerous groundings on record indicate that failure to identify the forts has occurred, even with local knowledge, and during relatively favorable conditions with radar in operation. Ships mistaking the harbor works at Futtsu, located eastward of Futtsu Saki, for Fort No. 1 is probably the principal reason for the groundings.

Ships transiting the section of Uraga Suido Traffic Route between Channel Buoys Nos. 4 and 5 are to exercise caution in the vicinity of Daison Kaiho (Fort No. 3) and the dangerous shoal surrounding it. This shoal extends outward to 200 yards (183 m). Ships are prohibited from entering, leaving, or crossing the Route in this section.

Ships should pass to starboard of the midchannel buoys, moored in Uraga Suido to alleviate the congestion that endangers shipping. Outboard traffic should be particularly cautious of inbound ships crossing the outboard traffic lanes for destinations westward of the Uraga Suido Fairway.

The Tokyo Wan Traffic Advisory Service Center (TASC) is situated about 0.2 nmi northwest of Kannon Saki Light. The purpose of the center is to provide vessels with information, to control traffic routes, and to ensure the safe navigation of vessels leaving or entering Tokyo Wan. Currently, Japanese Traffic Advisory Service (VTS) Centers are operated in six areas: Tokyo-wan, Nagoya-ko, Osaka-wan, Bisan-Seto, Kurushima-kaikyo and Kanmon-kaikyo. Per the Fleet Guide, all USN ships entering or departing Tokyo Wan will make maximum use of the services provided by the TASC. Contact with TASC (Call sign Tokyo Martis), can be made utilizing VHF Channel 16. All ships entering or departing Yokosuka should monitor VHF Channel 16 three hours prior to arrival/departure Tokyo Wan.

In view of the possibility of serious marine accidents in these channels, the Yokohama Maritime Safety Division, which is responsible for these channels, has established safety rules for all ships navigating Uraga Suido and Naka-no-Se. Vessels having a length of 50 m or more are obliged to follow the traffic routes. Ships should carefully observe the directions, signals, and traffic routes mentioned and the Japan Maritime Safety Laws and Regulations. The Maritime Traffic Safety Law of Japan must also be used with the applicable charts. Vessels navigating Uraga Suido Traffic Route should keep to the starboard side of the centerline of the route. When a vessel intends to navigate the Naka-no-Se Traffic Route along the course of the route, the vessel should navigate northward.

The Japan Maritime Traffic Safety Law became effective as of 1 July 1973. This law applies to all ships, including USN vessels transiting the sea areas of Tokyo Wan. USN ships transiting to Yokosuka Ko are affected. Though the law contains specific requirements for vessels carrying dangerous cargo, all USN ships have officially been exempted from these portions of the law.

Per the Fleet Guide, the following major points of the law are outlined for information:

  1. Identity of sea areas and traffic lanes affected: Uraga Suido Traffic Route and Naka-no-Se Traffic Route in Tokyo Wan.
  2. Classification of vessels and special rules (as applicable to USN ships). It is required that the Maritime Safety Agency (MSA) be notified no later than 72 hours prior to the transit for any of the following vessels transiting the traffic route:
    • Huge Vessels: All ships over 656 ft (200 m) or more in length. Additionally, these vessels will display at night an all around green light flashing at frequencies of 180 times per minute in addition to standard running lights and by day, two black cylindrical shapes (2 by 3.9 ft (0.6 by 1.2 m) or greater) placed vertically while transiting the traffic route.
    • Vessels of 10,000 gross tons or greater.
    • Vessels towing or pushing objects if distance between bow of towing vessels and stern of towed object or distance between stern of pushing vessel and bow of object is 656 ft (200 m) or greater.
  3. All vessels under this law shall make their notification by message to COMNAVFORJAPAN, info COMSEVENTHFLT, appropriate TASK FORCE COMMANDER, and COMFLEACT YOKOSUKA referencing this law in time to meet the notification due time.
    1. The following is the notification format:
      1. Waters to be transited (Tokyo Wan).
      2. Name/Gross Tonnage.
      3. Length in Meters.
      4. Draft in Meters.
      5. Dangerous Cargo (N/A for USN vessels).
      6. Distance between bow of towing vessel to stern of tow or distance between stern of vessel and bow of pushed object (applies to vessels towing or pushing).
      7. Description of object (applies to vessels towing or pushing objects).
      8. Port of Destination .
      9. Traffic Route (Uraga Suido).
      10. ETA Buoy Nr.
      11. ETD Buoy Nr.
      12. International call sign.
      13. Method of communications with MSA (N/A for USN).
      14. COMNAVFORJAPAN Yokosuka Japan .
    2. In Addition to the above requirements, a voice report of position to Tokyo Wan Traffic Advisory Service Center (TASC) is required for entry into the system.
      1. Format Example:
        1. Name of Vessel.
        2. Abbreviation of reporting line (US/UW) ( Figure V-31 ). US Line (inbound vessels) is a line drawn 270 ° from Hamakanaya-Ko breakwater lighthouse (35 ° 10.1'N 139 ° 49.2'E). UW Line (outbound vessels) is a line drawn from a point 090 ° - 9,843 ft (3,000 m) from Koshiba Saki to a point 090 ° - 3,281 ft (1,000 m) from Kannon Saki Lighthouse (35 ° 15.2'N 139 ° 44.6'E).
        3. Estimated time of passing.
    3. The law, as currently written, directs that a vessel is not to proceed through a traffic route until an acknowledgment of the receipt of notification is received from MSA.
  4. Other points of the law:
    1. A southbound vessel leaving Uraga Suido Traffic Route should not take such action as altering course sharply that might impede the passage of a vessel entering the traffic route.
    2. A vessel entering Uraga Suido Traffic Route from the open sea after passing through the Ken Saki should navigate in the middle part of the entrance of Tokyo Wan so as to avoid a crossing situation with a southbound vessel in the vicinity of the entrance of the route.
    3. Restriction on overtaking huge vessels and vessels 10,000 grt or more, except when there is an unavoidable reason.
    4. Restriction on entry into the traffic route in poor visibility. Vessels of 10,000 grt or more, except huge vessels and vessels 10,000grt or greater carrying dangerous cargo, should not enter the traffic route in cases when the visibility in the traffic route and its vicinity is less than 1,000 m. Huge vessels and vessels over 10,000 grt carrying dangerous cargo, should not enter the traffic route when visibility is less than 1 nmi.
    5. All vessels over 100 tons or 164 ft (50 m), must comply with the traffic rules applicable to the individual traffic route, including the display of the destination signal, as specified, when arriving from sea.
  5. Obligation to navigate traffic routes: Vessels whose length is 164 ft (50 m) or greater should proceed within a traffic route in the area where there is such a traffic route.
  6. Restriction on speed of a vessel: Vessels should not navigate at a speed exceeding 12 kt in any areas of Urago Suido.
  7. Restrictions on entering, leaving, or crossing Traffic Route : No vessels are permitted to enter, leave, or cross the traffic routes in the designated sections of Uraga Suido Traffic Route .
  8. Ships transiting Uraga Suido will display specified signal flags by day, or whistle signals by night when passing or approaching other ships near the exit of the traffic route. The following signals apply:
    1. By day:
      1. Kisarazu: 1 st Substitute �Sierra.
      2. Yokosuka : 1 st Substitute-Papa.
      3. Yokosuka to Naka-no-Se Traffic Route : 2nd Substitute-Charlie.
      4. Negishi/Thru Naka-no-Se Traffic Route to Kawasaki :
      5. 2 nd Substitue-Papa.
    2. By Night (Whistle/Horn):
      1. Kisarazu: 2 Prolonged Blasts, 1 Short Blast, 1 Prolonged Blast.
      2. Yokosuka : 2 Prolonged Blasts, 2 Short Blasts, 1 Prolonged Blast.
      3. Yokosuka to Naka-no-Se Traffic Route : 4 Prolonged Blasts.
      4. Thru Naka-no-Se Traffic Route to Chiba : 3 Prolonged Blasts, 1 Short Blast.
      5. Nicosia/thru Naka-no-Se Traffic Route to Kawasaki : 3 Prolonged Blasts, 2 Short Blasts.
    3. Note that night destination signals for ships transiting Uraga Suido Traffic Route should be sounded three times:
      1.  
        1. At midchannel buoy.
        2. As ship approaches midchannel buoy.
        3. When commencing turn toward Yokosuka Ko.
  9. Signal to be given when overtaking other vessels: Vessels equipped with a whistle should give the following signal when they intend to overtake other vessels in the traffic route:
    1. When intending to navigate on the starboard side of the other vessels, they should give one prolonged and one short blast in succession on the whistle.
    2. When intending to navigate on the port side, they should give one prolonged and two short blasts in succession on the whistle.
  10. Method of crossing traffic routes: Vessels crossing traffic routes should cross promptly at angles close as possible to right angles to the traffic routes.
  11. Prohibition of anchoring: No vessels are permitted to anchor in the traffic routes. Mooring to vessels at anchor will be regarded as anchoring.
  12. Traffic separation: Within the Uraga Suido Traffic Route, all vessels should navigate in that portion of the traffic route that lies on the starboard side of the centerline of such route. Ships heading north will remain in the eastern half of the channel and in the western half heading south.
  13. Definition of Uraga Suido Channel in Tokyo Wan. The channel definition is:
    1. 320 ° /8,531 ft (2,600 m) from Daini Kaiho Light.
    2. 280 ° /1,050 ft (320 m) from Daini Kaiho Light.
    3. 090 ° /12,140 ft (3,700 m) from Kannon Saki Light.
    4. 090 ° /15,257 ft (4,650 m) from Ashika Shima Light.
    5. 090 ° /9,515 ft (2,900 m) from Ashika Shima Light.
    6. 090 ° /6,398 ft (1,950 m) from Kannon Saki Light.
    7. 300 ° /12,796 ft (3,900 m) from Daini Kaiho Light.
  14. Channels and depths: There are no channels as such in Tokyo Wan, with the exception of the approach channels leading into Tokyo Ko and Yokohama Ko. Elsewhere, navigation is governed by existing depths. In general, most dangers within the bay lie within 2 nmi of shore. Depths in Tokyo Wan decrease gradually from about 20 fathoms (36.6 m) at the narrows to 5 fathoms (9.2 m) near the head of the bay.

Additional information taken mostly from the Sailing Directions that might not have been addressed above is included below:

A vessel (other than a huge vessel) navigating so as to involve risk of collision with a huge vessel navigating Uraga Suido Traffic Route and intending to enter Naka-no Se Traffic Route, shall keep out of the way of a huge vessel.

Huge vessels navigating Uraga Suido Traffic Route shall keep out of the way of huge vessels intending to enter Naka-no-Se Traffic Route .

Southbound vessels navigating through the west area of Naka-no-Se should pass Naka-no-Se Traffic Separation Lighted Buoy No. 1, Traffic Separation Lighted Buoy No. 2, and Traffic Separation Lighted Buoy No. 3 on their port hand ( Figure V-32 ).

Northbound vessels navigating through the west area of Naka-no-Se except those enroute Negishi Section 5, Yokohama Ku and Keikhin Ko, should pass the separation lighted buoys on their port side until they have set their course for their destination.

Northbound vessels, with draft 17 m or over, should pass at a distance of 400 m from the line that connects Lighted Buoy A, Lighted Buoy B, Lighted Buoy C, and Lighted Buoy D at Naka-no-Se.

Vessels wishing to anchor in the west area of Naka-no-Se should do so at a distance of 1,000 m from the line that connects the lighted separation buoys.

A vessel of 50,000 grt or more carrying dangerous cargo, or a vessel of 25,000 grt or more carrying liquefied gas, is prohibited from entering the traffic routes from sunset until 1 hour before sunrise.

A vessel navigating in Tokyo Wan should not use an automatic pilot.

Sailing rules in the vicinity of each entrance and exit of the traffic routes:

  1. A vessel navigating in the vicinity of the north exit of Naka-no-Se Traffic Route leaving Kisarazu Ko should pass Kisarazu Ko Lighted Buoy (35 ° 24.9'N 139 ° 47.2'E) on its port side.
  2. A southbound vessel from Tokyo or its vicinity in the offing of Kawasaki should pass Kawasaki Ku Lighted Buoy No. 2 on its starboard side at a distance of 3,281 ft (1,000 m) or more.
  3. A southbound vessel in the area west of Naka-no-Se should keep a distance of 3,281 ft (1,000 m) or more from Tokyo Wan Naka-no-Se Lighted Buoy D, Lighted Buoy C, and Lighted Buoy B on its port hand. A vessel intending to anchor west of Naka-no-Se should keep at least 1 nmi from a line joining Lighted Buoy B, Lighted Buoy C, and Lighted Buoy D.
  4. A southbound vessel from Tokyo , Chiba , or their vicinity, approaching Naka-no-Se at an oblique angle, should navigate on the west side of Tokyo Wan Naka-no-Se Lighted Buoy A, keeping distance as far as practicable.
  5. A southbound vessel leaving Uraga Suido Traffic Route should not take such action as greatly altering its course that might impede the passage of a vessel entering the traffic route.
  6. A vessel entering Uraga Suido Traffic Route from the open sea, after passing through the Ken Saki, should navigate in the middle of the entrance of Tokyo Wan so as to avoid a crossing situation with a southbound vessel in the vicinity of the entrance of the route.
  7. Restriction on Overtaking. Huge vessels or other particular types of vessels in the traffic route should not overtake a vessel of 500 grt or more, except when there are unavoidable reasons.
  8. Restrictions on Speed. A vessel shall not navigate at a speed exceeding 12 kt in the traffic routes. Outside the traffic routes, vessels should not navigate at a high speed.
  9. Notification of Traffic Routes and Notification of Change. A vessel of 10,000 grt or more should give the �Notification of Traffic Routes� and the �Notification of Change� as set forth for a huge vessel.
  10. Position Report. Huge vessels, other particular types of vessels, and vessels of 10,000 grt or more intending to enter or leave Tokyo Wan or shift positions in the bay, should report their positions to Tokyo Wan Traffic Advisory Service Center when they arrive at the first reporting line.
  11. Maintenance of Communications with the Center. Huge vessels, other particular types of vessels, and vessels of 10,000 grt or more should guard VHF Channel 16 while navigating within the radar service of the center even after leaving the traffic route.
  12. Vessels of 10,000 grt or more may not enter the traffic route when the visibility is less than 0.5 nmi, except with the permission of the maritime Traffic Advisory Center .
  13. Provision of Emergency Fire Wires. A vessel carrying dangerous cargo specified in the Maritime Traffic Safety law should provide, on board, the following emergency fire wires and auxiliary ropes, on her bow and stern.
    • Fire wires, with an eye on the end, strong enough to tow the vessel and long enough to reach the water.
    • Auxiliary ropes, with an eye in the end, strong enough to lead the fire wires to the water surface, hanging down by the board, as close to the water surface as practicable, without impeding safe navigation.
  14. The owner or operator of tankers of 220,000 dwt or more carrying dangerous cargo into Tokyo Wan for the first time should first submit �The Written Pledge for Safety Measures� to the Maritime Safety Agency and fulfill its requirements. These same requirements apply also to liquefied gas tankers of 25,000 grt or larger, entering Japanese waters for the first time.

Vessels can communicate by radio with the coastal radio station at Yokohama . The stations call sign and call name are JGC and Yokohama-hoan. The watch frequencies are 500 KHz, 2,182 KHz, 156.8 MHz, and 444 KHz, 2,150 KHz, 156.6 MHz, respectively.

The fairway in the vicinity of Daini Kaiho (Fort No. 2) and Daisan Kaiho (Fort No. 3) is heavily congested, making radar identification of the forts difficult (Figure V-33). Vessels have grounded by confusing Daini Kaiho for Daiiti Kaiho (Fort No. 1), mistaking Daiiti Kaiho for Futtsu Harbor , or the inability to identify Daisan Kaiho. Care should also be taken particularly in the vicinity of Daisan Kaiho (Fort No. 3), due to the dangerous shoal areas surrounding the fort. Entering, leaving, or crossing the route in the section between Buoy No. 4 and Buoy No. 5 is prohibited.

Note that the Fort No.3 Removal Project and Nakanose Traffic Route Dredging project (Tokyo Bay Entrance Route Construction) was implemented in 2000 and will continue for approximately 7 years. During this time the navigation area will be narrowed, temporarily, in waters in the project's vicinity. Normally the Nakanose Traffic Route dredging project takes place from February to August of each year, and the passable width of the Nakanose Traffic Route may be less than half of the normal width ( Figure V-34 ) .

The narrows between Kannon Saki and Daini Kaiho, about 3.3 nmi N, constricts the north part of Uraga Suido and forms the inner part of Tokyo Wan. The least width in the narrows, between the 65.6 ft (20 m) curve is about 2 nmi.

The west shore of Tokyo Bay extends about 1 nmi northwest of Kannon Saki to Hatayama Saki. Most of this coast is fronted by a seawall, which makes it conspicuous. From Hatayama Saki, the coast extends in a bight about 3.5 nmi west-northwest to the peninsula that forms the east side of Yokosuka Ko. The bight thus formed contains numerous dangers that lie up to 1.5 nmi offshore. Sara Shima lies in this bight about 0.75 nmi offshore.

Yokosuka Ko is a designated Special Port , Open Port , Quarantine Port , and Port of Entry. It includes the water area between Kannon Saki and the quarantine anchorage north of the northeast breakwater as shown on Chart # 97146. The Port is a building and repair facility and comprises the bays of Nagaura Ko, Yokosuka Ko, and Otsu Wan. The port complex is divided into seven port districts, No.1 through No. 7. The island of Azuma Hanto lies between Nagaura Ko and Yokosuka Ko. A hill, with a flagstaff and signal station on its summit, rises near the southwest part of Azuma Hanto. The inner part of the Harbor, shown as section I on Chart # 97146, is the part commonly referred to as Yokosuka Ko (Harbor). It is entered between Azuma Saki on the western side and Hanare Hajima on the eastern side. The Harbor is 1 nmi long and has a maximum width of about 0.5 nmi. It is bounded on the east by the peninsula that is the site of Fleet Activities. Most of the facilities in Yokosuka Ko are for the use of the Navy. District No. 1 through District No. 4 include the dockyard of Yokosuka Ko, Nagaura, the inner approaches to Yokosuka Ko, and the outer approaches, respectively. Kurihama Wan, Uraga Ko, and Otsu Wan are also included within the harbor limits of Yokosuka Ko and lie, respectively, in District No. 5, District No. 6, and District No. 7.

Yokosuka Ko Lightbuoy #1 marks the northeast side of a 48 ft (14.6 m) patch 1 nmi northeast of Katsuriki Saki. A light tower stands at the southeast end of the Northeast Breakwater. East Breakwater with a light tower at its north end, lies in a north northwest/ south southeast direction close north of the west end of Northeast breakwater. A light is exhibited from the head of a breakwater 0.4 nmi east of Yasuura Ko.

The depths vary from 39.4 to 49.2 ft (12 to 15 m) in the passages and from 49.2 to 118 ft (15 to 36 m) in the anchorages.

Signals are displayed from the signal station on Azuma Hanto. Another station is at the Harbor Office at the head of Yokosuka Wan. Local storm warnings are displayed at the Naval Meteorology and Oceanography Center located on a hill overlooking the Navy Exchange complex and from the signal station on Hoha To.

In addition to the regular aids in this area, numerous buoys for Naval use are moored about the harbor, and other lights are situated on piers, landing stages, etc. An obstructed fish haven lies about 4 nmi east of Kurihama Wan. Another fish haven lies nearly 2 nmi northeast.

Dangerous wrecks lie in the approaches to Yokosuka Ko, about 1.3 nmi southeast of Okino Ne and 2.3 nmi southeast, as indicated on the chart. A dangerous wreck is charted in the approach to Section I, about 0.5 north-northeast of Hanare Hashima, but was reported removed in 1983. It has been reported (1997) that a foul ground lies 0.6 nmi east of the pilot boarding area. Okino Ne, with a least depth of 18.4 ft (5.6 m), lies in the northeast part of the quarantine anchorage and is marked close south by a lighted buoy. A submarine cable is laid between a position about 0.5 nmi southwest of Northeast Breakwater Light and the shore southwest.

Koshiba Saki (35 ° 21'N 139 ° 39'E) marks the north limit of Yokosuka Ko and the coast trends north for about 1.8 nmi to Konosu Bana, the south limit of Yokohama Ko. The land east of Koshiba Saki is being reclaimed to a distance of about 0.7 nmi. The land north and south of the point is also being reclaimed to an even larger extent. The waters southwest of Koshiba Saki are within a prohibited area.

The preceding regulations and information were taken primarily from the Sailing Directions (Pub. 158) and Pacific Fleet Guide (Pub. 941) and are not all-inclusive. Advance study of these publications in conjunction with Charts #97141, #97142, #97143, #97144, #97146, and #97120 and the Light List is recommended. Supplemental information was obtained through the Tokyo Wan Vessel Traffic Advisory Service Center (Tokyo MARTIS) web site http://www.kaiho.mlit.go.jp//syoukai/soshiki/toudai/navigation-safety/download/down_bc/english/mokuji.htm. The web site includes information on the Conditions in Sea Areas around Japan , Pilotage and Navigation Law, Information for Safe Navigation, and a Guide to Safe Navigation.

The USS HONOLULU (SSN-718) Port Visit Report from June 2004 indicated that Tokyo Martis was consistently busy with inbound/outbound traffic. Initial hail was on Channel 16 with an immediate shift to Channel 14. Operators were proficient in English. Honolulu recommended using GPS as the primary fix source for the entire inbound and outbound tracks. Visual fixes were less reliable, especially inside the Harbor after Uraga Suido. Many good visual NAVAIDS were not charted on Chart #97146 plus mountains and the USS KITTY HAWK obstructed many NAVAIDS as the submarine got closer to Berths 10 and 11. Danger ranges/bearings south of Uraga Suido for both the inbound and outbound tracks allowed for flexibility for the OOD to maneuver for contacts. On the inbound track, submarine was consistently pushed to the east due to contact density. USS HONOLULU recommended lining up to the right of Uraga Suido and shifting to the left of the traffic separation scheme for the turn into Yokosuka . USS HONOLULU used an outbound track of 296 ° , 237 ° , and 217 ° to the dive point from Uraga Suido. USS HONOLULU was consistently pushed to the west and north of track due to fishing vessels and eastbound merchants entering Tokyo Wan. On Chart # 97140 the USS HONOLULU was forced to cross an effective merchant transit lane from the southern tip of the Miura Peninsula ( Mikimoto Island ) to the Voluntary Traffic Separation Scheme west of O Shima Island.

The USS HELENA (SSN-725) Port Visit Report from August 2005 stated that bridge-to-bridge radio traffic on Channel 16 was nearly continuous. Tokyo Martis conducted initial call-ups on Channel 16 and directed ships to shift to either Channel 14 or 22. During her inbound transit the visibility was poor, averaging less than 200 yards (183 m) until USS HELENA entered the Traffic Separation Scheme. Sufficient radar NAVAIDS were available to use radar navigation. During the transit the ship's Furuno Radar was used primarily for radar navigation and the BPS-15H was used primarily for contact management. No significant currents were observed.


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