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» Forum Name: PT Boats - General
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» Topic: RON 33, 60MM mortars?
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Now that Travis B. has corrected and educated me regarding the size of mortars carried on boats, thanks Travis, I am pursuing any information that anyone might have that would indicate that RON 33 boats carried 60mm mortars, presumably for illumination rounds, and whether they were normally mounted on deck or stowed below and assembled for use as needed.
Thanks
Jonathan

Posted By: JEno | Posted on: Dec 5, 2019 - 10:00am
Total Posts: 72 | Joined: Oct 13, 2019 - 9:52am

PT 155, 334 364 366 and 491 all show what I believe to be 60mm mortars mounted onto the bow. in fact we used 364 (Obie Williams Boat) as the model for ours mocked up on PT658. The 366 photo shows Fall River Docent Matt Kudla manning 37mm with 60mm mortar in background.Ā Also the PT491 Photo has a boat in foreground with bare foredeck, then the boat next to it nested has what looks like a lifejacket placed around the base of something? It looks like it could be a 60mm mortar or maybe aĀ Browning 1919 30cal mg? Those boats are in RON33 which is what Jonathan is looking for. I also threw in a picture of nested PT490 and 491 and cant see any mortar on their decks.

PT 334 RON 24.

PT 155 60mm mortar.

PT 364 Crew.

PT366 37mm MattKudla.

PT491 Ferdinand Bull.

PT 490, 91, 95 nested

Jerry Gilmartin
PT658 Crewman
Portland OR

Posted By: Jerry Gilmartin | Posted on: Dec 6, 2019 - 7:16am
Total Posts: 1472 | Joined: Oct 8, 2006 - 11:16pm

Nice images, thank you Jerry! The ring mounted mortar on PT 155, could that be an 81mm? It looks larger than the 60's. As does this one, I have it labeled as PT 84. Would you happen to have an image that shows the mount better?:

Here's an image from the manual:

The 60mm looks quite small:

Compared to the ring mounted ones:

Posted By: Jeff D | Posted on: Dec 6, 2019 - 8:19am
Total Posts: 2200 | Joined: Dec 21, 2006 - 1:30am

Many Thanks Jerry and Jeff.
Jonathan

Posted By: JEno | Posted on: Dec 6, 2019 - 10:12am
Total Posts: 72 | Joined: Oct 13, 2019 - 9:52am

The next to last photo of PT 361 posted by JeffD is from my father's collection and shows GM1C Al Wilson at the mortar and GM2C Al Heimke sitting on the ammo box. One thing I noticed is that the mounting base appears to be different for all or most of the 60 mm mortars shown in this thread, the one on the 361 appearing to be a fabricated metal pan with a sloped back and loaded with sand bags. Other pictures of the mortar on the 361 show it in the same relative position and with the sandbags present. Although a posed picture it appears that Wilson is kneeling on the mortar base with his right leg. I wonder if that was SOP.

I have another picture of GM1C Harold Wilson in a similar posed photo at a 60 mm mortar on PT 360. The base plate of the mortar is not visible in that photo. Would the RON 27 boats had similar fixtures. The mortar on the 360 is located more towards the centerline of the boat and aimed to starboard, however they should be fairly easy to move.

Finally, I have a picture of PT 377 'Cruncher', also of RON 27 (I believe) with an 81 mm mortar with the large circular base. I previously posted that picture here, so it might be in the archives. It was taken immediately after the war ended and shows a Japanese surrender party and Australian officers on the 377.

Al Wilson (PT 361) and Harold Wilson (PT 360) mentioned above were brothers and Dad said that the 359, 360 and 361 frequently patrolled together. Didn't the Navy have a requirement against siblings being on the same ship after the loss of the Sullivan brothers? If so, the Wilson brothers probably served as close together as possible without being on the same ship/boat!

Randy McConnell (Randall J. McConnell III)

Posted By: PRJM3 | Posted on: Dec 7, 2019 - 12:16pm
Total Posts: 94 | Joined: May 25, 2009 - 2:47pm

I agree with you some of these taller mortars in the photos do appear to be an 81mm. Also have an idea/guess about the "Ring". I wonder if they took an old scarph ring from a twin 50 cal gun mount and used it for the mortar so you could turn it easily? These rings bear a striking resemblance to the 50 cal gun mount rings. Dave asks "Would you happen to have an image that shows the mount better?" sorry no these are all I have.

Jerry Gilmartin
PT658 Crewman
Portland OR

Posted By: Jerry Gilmartin | Posted on: Dec 7, 2019 - 12:27pm
Total Posts: 1472 | Joined: Oct 8, 2006 - 11:16pm

http://www.navsource.org/archives/12/120548601.jpg

In this photo, 545 appears to be mounting a 81mm just forward of her starboard forward torpedo, next to the officer sitting..

Posted By: JEno | Posted on: Dec 7, 2019 - 1:55pm
Total Posts: 72 | Joined: Oct 13, 2019 - 9:52am

Thanks Randy, it is good to put names to the faces. I see what you mean, there's a number of different bases. I suspect that the 60mm mortars weren't nailed down like other armament was.

I think this is the photo of the 377 you mentioned Randy:

PT 131 with a 60mm mortar sitting on top of the chart house. She's also carrying beach barrage rockets in eggcrate launchers:

After you mentioned it, I thought the ring was from a Mark 17 .50 mount too Jerry. They even have what looks like the same brake on them. But I found a better image of one and it doesn't look quite right. Maybe it's from some Army warwagon?:

A 60mm on PT 181:

You can see a 81mm on the far left boat, possibly PT 545. This was taken at MTBSTC. The 559 has a Thunderbolt mounted:

Posted By: Jeff D | Posted on: Dec 8, 2019 - 5:39am
Total Posts: 2200 | Joined: Dec 21, 2006 - 1:30am

Jeff,

Yes, that is the picture of the 377 that I was referencing. The officer leaning on the chart house with his hand on his hip is Mel Everingam, the skipper of the 377. The picture was taken by Chuck Welsh, skipper of the 359. My father was on a troop transport back to the US when the war ended and Welsh sent him a copy of the picture. Dad had commented that the two Japanese soldiers that are smoking almost certainly got the cigarettes from the Americans. They had none of their own and really enjoyed getting them. I have other pictures of Japanese prisoners being transported on RON 27 boats and some of them are also smoking cigarettes provided by the US sailors. I've also noticed in the 377 picture that the machine guns are not armed.

All information I can find online at the moment for the M1 81mm mortar shows it being in three parts; the tube, a bipod mount and a base plate. However, I am certain there was a version with a circular track that was used for vehicle-mounted M1s such as in the M4 Scout Car. I also recall that the Scout Cars had a baseplate and bipod carried on the side of the vehicle so that the tube could be removed from the vehicle for ground mounting. My guess is that's the version seen on the PT boats. I have several books on Scout Cars and will dig into them later today. A similar concept was applied to the Viet Nam-era M125 and M106. These were variants of the M113 Armored Personnel carrier that had 81mm and 107mm mortars, respectively mounted on circular tracks. Both could have the mortar removed for ground firing.

Randy McConnell (Randall J. McConnell III)

Posted By: PRJM3 | Posted on: Dec 8, 2019 - 7:21am
Total Posts: 94 | Joined: May 25, 2009 - 2:47pm

Once again thank you Randy, good info and I look forward to what you come up with.

Posted By: Jeff D | Posted on: Dec 8, 2019 - 4:45pm
Total Posts: 2200 | Joined: Dec 21, 2006 - 1:30am

It appears I was off track, so to speak, about a possible source of the circular track for the 81mm mortars. Of the various vehicle mounted, WWII-era mortars that I found the greatest listed traverse capability was 90 degrees. The rear compartments of those vehicles wasn't large enough for a full circle track. Even the compartment of the Viet Nam-era M113-derived mortar carriers wasn't big enough for a 360 degree traverse 81mm mortar, although the 60mm version did appear to have a full circle base plate inside the vehicle.

It seems like I've seen the WWII 81mm circular track somewhere, so, the search continues.

Randy McConnell (Randall J. McConnell III)

Posted By: PRJM3 | Posted on: Dec 9, 2019 - 6:44am
Total Posts: 94 | Joined: May 25, 2009 - 2:47pm

I've been looking too, I'm afraid I've become obsessed with mortars now THANKS JONATHAN AND TRAVIS!!! [:-laughing-:]

No luck with a ring mounted one though, I thought I had a lead when I came across landing craft converted into mortar gunboats under the designation LCI(M) but so far nothing on a ring mount. I did come across an awesome ship mortar called Old Abe, the thing must have weighed a ton or 5:

Posted By: Jeff D | Posted on: Dec 9, 2019 - 12:09pm
Total Posts: 2200 | Joined: Dec 21, 2006 - 1:30am

Wow!

Will

Posted By: Will Day | Posted on: Dec 11, 2019 - 12:08pm
Total Posts: 1955 | Joined: Oct 8, 2006 - 4:19pm

I did find this from olive-drab.com:
"The 81mm M1 Mortar was developed for use in World War II from a French design. The 136 pound M1 was designed to be man-portable when broken down into three components, the tube, the bipod mount, and the round baseplate, each about 45 pounds. The rectangular base plate allowed for firing in any direction. In its mechanized version, the M1 rode in the M4, M4A1 and M21 half-track Mortar Carriers. The photo to the right is an 81mm M1 Mortar preserved at the Highland Lakes Museum, Burnett, TX. "
A photo showing the rectangular base was include.
I noted that is was designed with a round base plate. Would it be too much of a stretch to conclude that the "ring " mount seen on boats was around base plate field adaptation?
Jonathan

Posted By: JEno | Posted on: Dec 13, 2019 - 2:54pm
Total Posts: 72 | Joined: Oct 13, 2019 - 9:52am