Truck lagoon

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Brady
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Truck lagoon

Post by Brady » 18 Aug 2021 18:03

Hi-

Some time ago I recall reading that Truck lagoon's entrances were mined to effectively close down traffic through all but the southern entrance, by the Japanese themselves.

1) When did they do this ?

2) What tenders were Present to accomplish this and maintain it ?

3) Was this in effect throughout the war ?

ROLAND1369
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Re: Truck lagoon

Post by ROLAND1369 » 19 Aug 2021 02:11

Here is a summary of what was found at the end of the war at Truk in 1945. As to minelaying vessels the publication lists a 296 ton ocean capable SPECIAL MINELAYER NO 3. Data is from:
CINCPAC CINCPOA BULLETIN NO 3-46, FIELD SURVEY OF JAPANESE DEFENSES ON TRUK.
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Brady
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Re: Truck lagoon

Post by Brady » 19 Aug 2021 02:40

Thank you, very helpful, I wonder how much of this was done prewar and simply maintained.

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fontessa
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Re: Truck lagoon

Post by fontessa » 19 Aug 2021 10:56

Hello Brady,
Brady wrote:
19 Aug 2021 02:40
I wonder how much of this was done prewar.
The below is the chart in Senshi Sosho Vol.38 中部太平洋方面海軍作戦(1)昭和十七年五月まで [Central Pacific Area Navy Operation (1) Until May 1945]
It shows the Minefields in Truck Lagoon in December 1941.

Japan's defense of the Trust Territory of the South Pacific was restricted by the Washington Naval Treaty, but was promoted during the non-convention era. The chart below is a conceptual diagram of Truck defense including the land batteries.


トラック諸島_機雷源.jpg

fontessa
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Brady
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Re: Truck lagoon

Post by Brady » 19 Aug 2021 15:09

That is extremely helpful, especially since I can compare and contrast the two and see how the defence developed during the war.

Is there any information on the depths of these passes?

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fontessa
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Re: Truck lagoon

Post by fontessa » 19 Aug 2021 18:18

Hello Brady,
Brady wrote:
19 Aug 2021 15:09
Is there any information on the depths of these passes?
Fragmentally. .. .. The source is not the Senshi Sosho. .. .. I don't know correctly which pass IJN used. Northeast Pass?
Otajima Pass: Width was 700m or more. There were shallows with a depth of 10m. It was difficult for large ships to pass.
West Pass: Dotted with shallow water. Not suitable for traffic other than small ships.
South Pass: Approximately 450m wide. Large ships could pass. However, the tide was fast.
Sarashima Pass: 250m wide. Shallow waters with a depth of about 7m were scattered inside, and it was not possible to pass more than light cruisers.
Hanashima Pass: 200m wide. However, there shallows of about 4m.
Northeast Pass: Ideal for entering and exiting the lagoon. There was a lighthouse and it is possible to pass even at night.
Torashima Pass: Shallows in the center. The waves were rough, so it was not suitable for ships.
Evalite Pass: Approximately 350m wide There were no obstacles and large ships can pass through.
Ushijima Pass: The width was 100m and narrow, but there were no obstacles.
North Pass: Many shallows inside. When the wind was northeast, the waves are relatively calm and ships could pass if they follow buoys.


トラック諸島_機雷源_改.jpg

fontessa
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Brady
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Re: Truck lagoon

Post by Brady » 20 Aug 2021 00:29

Brilliant, very helpful, Thank You

ROLAND1369
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Re: Truck lagoon

Post by ROLAND1369 » 24 Aug 2021 01:44

For what it is worth here are the comments on the development of the defense follows. This is from the same US Government report I quoted earlier
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Brady
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Re: Truck lagoon

Post by Brady » 24 Aug 2021 01:59

That helps to fill in the picture a bit better.

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