COMPARATIVE VALUE OF TARGETS
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REQUIREMENTS FOR AIR ASCENDANCY Tab B Japanese Theatre - Appendix J-II Submarine Yards |
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No. |
Name and Location |
No. of Submarines Built |
Percent of Known Total |
|
|
1. |
Mitsubishi |
Kobe |
26 |
36 % |
|
2. |
Kawasaki |
Kobe |
18 |
25 |
|
3. |
Sasebo Navy Yard |
Sasebo |
11 |
15 |
|
4. |
Kure Navy Yard |
Kure |
9 |
13 |
|
5. |
Yokosuka Navy Yard |
Yokosuka |
8 |
11 |
|
|
|
TOTAL |
72 |
100 % |
|
SUMMARY: This tabulation shows the number of submarines known to have been built in these shipyards from 1925 to date. No information is available concerning the number of submarines constructed in other yards. However, it may be assumed that all primary Japanese shipyards (naval and commercial) are equipped to construct submarines. For this reason, submarine shipyards alone are not to be considered among the high priority objectives in the Japanese Empire, but are to be considered in conjunction with naval bases and shipyards in general, covered in a separate section of this report. SUBMARINE BASES Information concerning submarine bases is too inadequate to permit of a complete listing. The known bases in Japan and along the adjacent coastline are shown on the accompanying map. Other submarine bases are known to be located in the Japanese Mandated Islands, as well as in Japan’s recently occupied territories, with definite locations for attack purposes to be established through local reconnaissance. |
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1. DESCRIPTION OF TARGETS
The main target comprises the slipways upon which submarines are built. The primary aim is to destroy the submarines themselves. However, it is also desirable to destroy the shipyard facilities, including the cranes, gantries, workshops, etc., if possible.
2. NUMBER OF DIRECT HITS AND TYPE OF BOMBS REQUIRED
In order to effectively destroy both submarines and shipyard facilities, it is considered that the weight of attack should be such that not less than fifty (50) direct hits are obtained within the aiming point area of 1000’ by 1000’ The construction of submarines and shipyards is such that it is considered that bombs of at least 1,000 lbs. will be required.
3. NUMBER OF SORTIES AND BOMBER FORCE REQUIRED
Based upon detailed calculations taking into account all operational factors involved in making attacks against highly defended targets with appropriate allowances for probabilities, aiming errors, losses, etc., etc. and allowing for the fact that with the very heavy weight of attack proposed, the destruction will be so considerable that no further attacks will be found necessary within a six month period, it appears that it would be necessary to have:-
1,260 SORTIES
In order to carry out these sorties in sixty (60) operational days, a force of:-
4 - B 29’s and
14 - B 17e's
must be set up.