Henry Sakaida has a chapter in his book The Siege of Rabaul (1996) dealing with the use of these drones in the Solomons. The demonstration mission against the beached Japanese freightet Yamazuki Maru went quite well, with two of the four drones that were launched successfully hitting and destroying the target.
Operationally things did not go quite so well. A total of 42 drones were launched against targets at Rabaul and on Bougainville. Sakaida provides details on the following attacks:
27 Sept 44 – 4 launches (Bougainville): 2 hits on ships in Kahili harbour, 1 near miss, 1 hit on an AA battery.
1 Oct 44 – 8 launches (Bougainville): 2 hits on AA batteries, 1 near miss, 2 wide misses, 2 duds/misses, 1 exploded in air en route to target.
5 Oct 44 – 4 launches (Rabaul): 2 lost en route, 2 far misses.
9 Oct 44 – 4 launches (Rabaul): 2 shot down by AA fire, 1 near miss, 1 far miss.
15 Oct 44 – 4 launches (Rabaul): 2 crashed en route, 1 hit far from target, 1 hit on a secondary target.
26 Oct 44 – 4 launches (Rabaul): 2 hits on buildings near the target, 1 crashed en route, 1 hit on targeted lighthouse.
Commander Tomoyoshi Hori, executive officer of the 105th Naval Base Unit, witnessed the first attack against Rabaul on 5 October and was quite dismissive: "Due to my experience, when I saw the first TDR attack at Rabaul at once I could understand what it was. I remember I saw its attack at Rabaul seven or eight times. Each time, our force suffered lightly and we didn't feel any sense of danger."
The US Navy was similarly unimpressed and reported: "Obviously in its present stage of development the assault drone is far less accurate and effective than the more ordinary bombing methods."
