http://www.etherit.co.uk/month/4/17.htm
May 17th, 1945 (THURSDAY)
UNITED KINGDOM: Submarine HMS Ambush laid down.
JAPAN: Okinawa: US marines today launched an assault on Naha, the capital, in an advance that is turning into the modern equivalent of Flanders trench warfare - a slow, bitter, muddy and bloody confrontation costing thousands of lives.
In the past six weeks the US Tenth Army has averaged barely 133 yards a day and its casualties are close to 20,000 - in excess of those on Iwo Jima. The worst losses have come in the last five days with the assault on three positions near Naha. During the action the marines suffered 2,662 casualties, many from crossfire from nearby hillsides. Further east the US 77th Infantry Division made swift progress today with a dawn raid bringing them close to Shuri, the heart of Japan’s defensive line.
JAPAN:
The USAAF’s Twentieth Air Force flies Mission 176: Between 0300 and 0600 hours local, 457 of 522 B-29 Superfortresses dispatched attack the Nagoya urban area in the last great attack on this city; the southern part of Nagoya, the site of the Mitsubishi Aircraft Works, Aichi Aircraft Company’s Atsuta plant and the Atsuta branch of the Nagoya Arsenal, the Nippon Vehicle Company and other targets are attacked from low levels; eleven other B-29s hit targets of opportunity; three B-29s are lost.
In an attempt to prevent kamikaze attacks, USAAF VII Fighter Command fighters from Iwo Jima fly 41 effective strike sorties against Atsugi, Japan; pilots claim ten parked aircraft destroyed. During the night of 17/18 May, two P-47 Thunderbolts of the 318th Fighter Group, presently arriving on Ie Shima (between 13 and 19 May), fly a heckling mission over Kyushu, Japan-the first such VII Fighter Command mission against Japan.
PACIFIC OCEAN: USS Ticonderoga (CV-14), with Carrier Air Group Eighty Seven (CVG-87) aboard, attacks Taroa Island in Maloelap Atoll as part of a training mission for the air group.
B 29’s lay mines
http://www.hartshorn.us/Navy/MinesAway.pdf
One example of a versatile aerial mine from World War II was the U.S. Navy’s Mark 25.16 The Army Air Forces laid many of these in 1944-45 and almost half of the mines laid in “Operation Starvation,” the mining of Japan’s home waters, were versions of this mine. Assembled, it weighed approximately 2,000 pounds, which included 1,250 pounds of explosive. The weapon looked much like a bomb with the exception of a half-slant shape to the nose (for improved underwater trajectory) and the parachute pack at the tail. After the mine left the aircraft a static line opened the parachute, which
lessened the shock as the mine entered the water. The Mk. 25 could be dropped from any altitude above 200 feet, at a maximum speed of 230 miles per hour, and used in water depths of 16 to 150 feet. Once the mine settled to the bottom it armed itself according to pre-flight settings and awaited its prey. Different models featured unique firing mechanisms (for magnetic, acoustic, or pressure actuation), clock starters and delays, ship counters, and redundant safety features. The minefield planner could select the Mk. 25 (or a smaller mine, such as the 1,000 pound Mk. 26) with modifications tailored to the specific water depth, type of vessels, traffic frequency, and minesweeping capability.