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» Forum Category: PT Boats of WWII
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» Forum Name: PT Boats - General
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» Topic: MK-50 Rocket Launchers
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I have enclosed photos of the MK-50 Rocket Launcher which was the type mounted on some of the late war boats. This was an 8-tube launcher designed for use on PT boats. Two launchers were mounted on each boat; they were swung inboard for loading and outboard for firing. The barrels are arranged in 2 rows of 4 each, 1 row above and the other below a horizontal supporting shaft. Elevation is adjustable, and train is effected by turning the PT boat. When a firing button is depressed (on the bridge), one rocket is fired from each launcher. Current to fire a motor is fed to a rocket by means of the contact ring. The electrical impulse passes from the contact ring to the squib, causing the latter to set off the black powder in the igniter.

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Posted By: Frank J Andruss Sr | Posted on: Mar 11, 2021 - 1:08pm
Total Posts: 3304 | Joined: Oct 9, 2006 - 6:09am



Going back to Frank's earlier post about the Mk-50 rocket launcher, does anyone know if these got much actual use on the PT boats and, if so, what were their intended targets and how effective were they?

I always thought that this type of rocket wasn't particularly accurate. However, a little research shows that the Mk-50 used a 5-inch rocket that was an improvement over the earlier and more commonly used 4.5 inch M8 rocket. Except for aircraft mounted M8s that benefited from the speed of the plane carrying them the M8 wasn't considered to be very accurate. That led to its being used for saturation attacks from calliope style launchers. The 5-inch rocket, which didn't appear to have an M-number, was higher velocity which reportedly improved its accuracy.

So, did the PT boats use them against individual targets or was it more of a barrage weapon? I could see them providing a significant punch when taking on armored barges. My Dad never talked about them; I suspect they weren't used yet in his area of operations.

Randy McConnell (Randall J. McConnell III)

Posted By: PRJM3 | Posted on: Apr 11, 2021 - 7:14pm
Total Posts: 69 | Joined: May 25, 2009 - 2:47pm



The first outstanding success of the PT rocket boats was scored in the Aitape landings; they knocked out 107 enemy craft of all varieties.

Soon most of the boats in Squadron Eight were also equipped with launchers; and by the end of the Aitape operation there were one or two PT boats with launchers in every squadron. Eventually some 60 PT’s in MTBRons Seventh Fleet were so equipped.

In addition to providing additional rocket fire in landing operations, PT boats were frequently used to harass enemy coastwise shipping. Off Ormoc, in December 1944, PT’s sank a Japanese lugger about 130 feet long with rockets alone. The PT boats, on patrol along shore, used their rockets against any targets that turned up—enemy trucks, bivouac areas, gun positions, supply dumps, concentrations of Japanese personnel.

By the end of 1944, MTBRons Seventh Fleet were using 2,500 to 3,000 barrage rockets per month.





Posted By: Frank J Andruss Sr | Posted on: Apr 12, 2021 - 5:27am
Total Posts: 3304 | Joined: Oct 9, 2006 - 6:09am



Thanks Frank, they did better than I had thought.



Posted By: Jeff D | Posted on: Apr 12, 2021 - 8:02am
Total Posts: 2066 | Joined: Dec 21, 2006 - 1:30am



To be honest this was the first time I heard of such success using rockets from the PT BOATS. It was part of the US Rocket Ordnance book, The development & use in WWII. printed in march 1946.



Posted By: Frank J Andruss Sr | Posted on: Apr 12, 2021 - 12:13pm
Total Posts: 3304 | Joined: Oct 9, 2006 - 6:09am