UKC & Depths

Question 1

⟡You are on a laden tanker preparing to enter Queens Gate, what is the maximum draft for a minus 1ft tide for the transit?

Answer 1

On the approach to Queen’s Gate, while in the channel, the controlling depth is 76 ft. Since the minimum UKC requirement for the Port of Long Beach is 10% of the vessel’s draft for the transit between the seabuoy and Buoy #3, a maximum draft of 69 ft is acceptable (69 ft + 6.9 ft = 75.9 ft). With a tide of -1 feet, the maximum draft is reduced by 1 foot to 68 ft.

Question 2

⟡You are on a ship entering the LA Pilot Area bound for berth 208. What is the required minimum UKC for the transit?

Answer 2

・For the transit between Buoy 1 and Buoy 11, the minimum UKC is 10% of the vessel’s draft. (With a controlling depth of 81 ft, the maximum draft is 73 ft).
・From Buoy 11 to a position off the berth, the minimum UKC is 2 ft. (With a controlling depth of 53 ft, the maximum draft is 51 ft).

Question 3

⟡What is the UKC required to transit the flats?

Answer 3

・Between the Long Beach seabuoy and the Long Beach Channel Buoy #3, minimum under-keel clearance before correction for roll and pitch is 10% of the vessel’s draft.
・Between the Los Angeles Approach Channel Lighted Buoy #1 and the Los Angeles Main Channel Buoy #11, minimum under-keel clearance before correction for roll and pitch is 10% of the vessel’s draft.
・Elsewhere in the main channels of Los Angeles and Long Beach, the minimum UKC is 2.0 ft until off of the berth.
・In the final approach to the berth, and while at berth, the vessel must always remain afloat.
・At anchorages inside the breakwater, minimum underkeel clearance is:
• 4.0 ft for anchorages B-7 and B-11 when vessels draft is 50 ft or more.
• 2.5 ft for all other anchorages.
・For shifts via outer harbor between Los Angeles and Long Beach, minimum underkeel clearance is 3.0 ft.

The answer is 3.0 ft in the flats (it is considered the outer harbor).

Question 4

⟡What is the controlling depth for the Los Angeles approach?

Answer 4

81 ft.

Question 5

⟡What is the controlling depth for the Long Beach approach?

Answer 5

76 ft.

Question 6

⟡Describe the Depths in 6 channels/berths in Los Angeles and 6 in Long Beach.

Answer 6

Los Angeles
・Approach and Entrance Channels: 81 ft.
・Pier 300 Turning Basin: 81 ft.
・Pier 300 Channel: 53 ft.
・Main Channel: 53 ft.
・East Basin Channel: 53 ft.
・Turning Basin: 53 ft.
・All other Channels and Basins: 53 ft.
Long Beach
・Main Channel: 76 ft.
・Back Channel: 52 ft.
・Inner Harbor (Turning Basin): 52 ft.
・Cerritos Channel: 50 ft.
・Channel Two: 37 to 55 ft.
・Channel Three: 36 to 45 ft.

Question 7

⟡Things to consider while considering UKC:

Answer 7

1. Vessel’s trim and list characteristics;
2. Depth of the transit area;
3. Depth at the facility or anchorage;
4. Tide and current conditions; and
5. Weather impact on water depth.

Question 8

⟡If you are transiting from LB78 to LA118 and transiting the flats, what is the minimum under-keel clearance and what is the UKC required?

Answer 8

“SO (before accounting for tides, pitch, squat, etc):
・To remain afloat at Dock LB78, the maximum draft is: 40.9 ft (the depth at the dock is 41 ft). {Afloat at all times}.
・To transit from the dock to the Inner Harbor via Channel Two from Dock LB78, the maximum draft is: 40 ft (the shallowest depth on the transit is 42 ft).
・To transit from the Inner Harbor to the LB Main Channel via the Back Channel, the maximum draft is: 50 ft (the controlling depth is 52 ft).
・To transit to the LA Main Channel via the flats, the maximum draft is: 37 ft (with the controlling depth being a 40ft obstruction between anchorages B-9 and B-10). This depends upon the route taken.
・To transit the LA Main Channel up to Buoy 11, the maximum draft is: 73 ft (controlling depth is 81 ft).
・To transit the LA Main Channel. past the Turning Basin and up the channel to the Southwest Basin, the maximum draft is: 51 ft (controlling depth is 53 ft).
・To transit rom the Turning Basin channel, through the Southwest Basin, to the dock, the maximum draft is: 36 ft (controlling depth for the transit is 38 ft).
・To dock at Dock LA118 and remain affloat, the maximum draft is: 35.7 (depth alongside the dock 35.8 ft). {Afloat at all times}.”

Question 9

⟡UKC factors to consider (5? factors)

Answer 9

Masters and pilots should use their vessel’s deepest draft in still water when calculating under-keel clearance. Masters and pilots should apply a plus or minus allowance for the tide when calculating depth of water, and consider the following factors:

1. Vessel’s trim and list characteristics;
2. Depth of the transit area;
3. Depth at the facility or anchorage;
4. Tide and current conditions; and
5. Weather impact on water depth.

Question 10

⟡Soundings range Between LA gate and VT bridge in main channel.

Answer 10

The U.S. Army Corps of Engineers maintain the Los Angeles Entrance Channel at 81 ft and the Los Angeles Main Channel at 53ft.
Deepest sounding is right at the gate at 88 ft. Shallowest sounding is just north of the range line at 52 ft (found at two different locations - one south of Reservation Pt. and the other near the western edge of the channel by Pier 1).

Question 11

⟡Minimum and maximum depths of Los Angeles Channel.

Answer 11

The U.S. Army Corps of Engineers maintain the Los Angeles Entrance Channel at 81 ft and the Los Angeles Main Channel at 53ft.
Deepest sounding is right at the gate at 88 ft. Shallowest sounding is just north of the range line at 52 ft (found at two different locations - one south of Reservation Pt. and the other near the western edge of the channel by Pier 1).
In the maintained channels in Los Angeles, the shallowest recorded sounding is in the Turning Basin, near the S tip of Mormon Island at 51ft.

Question 12

Soundings range Between LB gate and Middle Harbor in main channel.

Answer 12

75ft - 89ft.

Question 13

Soundings range of Back Channel in main channel.

Answer 13

52ft before Gerald Desmond Bridge.

Question 14

UKC Guidelines

Answer 14

Port of Los Angeles

1. Between Los Angeles Approach Channel Lighted Buoy #1 and Los Angeles Main Channel Buoy #11, minimum under-keel clearance before correction for roll and pitch is 10 percent of vessel’s draft.
2. In the channel between Los Angeles Main Channel Buoy #11and a position off the designated berth, minimum under-keel clearance is 2.0’ (0.61 m).
3. In the final approach to the berth, and while at berth, the vessel must always remain afloat.
4. Shifts via outer harbor between Los Angeles and Long Beach, minimum under-keel clearance is 3.0’ (0.91 meters).

Port of Long Beach:

1. Between the Long Beach sea buoy and the Long Beach Channel Buoy #3, minimum under-keel clearance before correction for roll and pitch is 10 percent of vessel’s draft.
2. In the channel between the Long Beach Channel Buoy #3 and position off the designated berth, minimum under-keel clearance is 2.0’ (0.61 m).
3. In the final approach to the berth, and while at berth, vessel must always remain afloat.
4. At anchorages inside the breakwater, minimum under-keel clearance is:
   a. 4.0’ (1.22 m) for Anchorages B-7 and B-11 when vessel’s draft is 50’ (15.24 m) or more, and
   b. 2.5’ (0.76 m) for all other anchorages.
5. Shifts via outer harbor between Los Angeles and Long Beach, minimum under-keel clearance is 3.0’ (0.91 m).

Question 15

What are the controlling depths in Fish harbor?

Answer 15

Fish Harbor Channel 14 feet
Fish Harbor 16 to 18 feet
Yacht Club Anchorage E of dredged channel 17 to 20 feet
Yacht Club Anchorage W of dredged channel 11 to 14 feet

USCP 7, Ch. 4, ¶ 278

Question 16

Describe local shoaling and silting in the POLA and POLB.

Answer 16

POLA and POLB do not have a siltation problem like natural river ports. The ports need only dredge occasionally to maintain berth side design water depths.

The harbors usually have very localized shoaling problems. They occur mainly in the immediate vicinity of the pierhead lines, when propeller or bow thruster action cause localized sloughing of the underwharf embankments. Soft bottom conditions mitigate the effect of shoaling.

LALB HSP (V) C