PBR question

Have you tried contacting the Mobile Riverine Force Association or Brownwater-Navy.com?

In Vietnam a favorite personal weapon on the PBR was the M14. Shared ammo with the 60 and was effective at some range from stationary position on a rail of the boat.

I'm running off of memory here (all my reference materials are packed away).

The Monitors & ATC's mounted--nominally--a 20mm flanked by two .50bmg in round "turrets" (really just splinter shields).

The Norwegian-built Nasty-class gunboats probably had 20mm mounts.  Some of the USCG craft mounted 20mm, too.

Ok, <ding!> memory kicks in; there were some Mk II PBR that had the dual .50's forward replaced by a single 20mm and a 10-12" xenon-lamped spotlight on the other side.  Without my reference material, I cannot recall if that was a field modification.

The ring mounts used for the dual 50's are the same as the WWII PT mounts, in case you want more source info to detail that forward PBR tub.

That would make sense. I have seen many other boats that did mount the 20mm but they were bigger. Because of the short distances and need for a lot of firepower they did prefer the 50 cals.

If you can come up with a picture or a book with a picture that would be great and I would really appreciate it.

I have seen so many pictures of PBRs both marks and they usually have the same weapons.

Running on memory, it's in one of the histories of Market Time; like as not,Brown Water, Black Berets.  But, it could be From the Rivers to the Sea, too.

Wish I could do better; I knew this would happen when I packed up all my stuff (foreclosure is not fun).

Both the PBR Mk I and PBR Mk II had weapons modifications installed during their service.  As CapnMac stated, I have seen various accounts that a 20mm Mk16-4 (not an Oerlikon) was mounted in the forward gun mount in both the Mk I and Mk II PBRs.  Some boats removed one .50 cal and mounted a 20mm in its place.  I have not been able to find any pictures of a 20mm mounted on a PBR and would be very happy if someone on the list could provide one.

The forward gun mount was a .50 cal twin scarf ring - the PBR Mk I used a Mark 36 and the PBR Mk II used Mark 56.  These are not the same as used on WWII PT boats, which was a Mark 17 mount (although the Mark 17 twin mount was used on the PCFs in Vietnam).  The Mark 56 Mod 2 mounted two 20mm Mk16-4 cannons.

I have seen a picture of a PBR Mk I that mounted a mini-gun in the forward scarf ring mount instead of the twin .50 cal mgs.

The aft .50 cal was modified on some boats and piggy-backed with a Mk18 40mm.  It was sometimes removed and replaced with a 60mm mortar or a 60mm piggy-backed with a Mk18 40mm. 

Some boats, both Mk I and Mk II, replaced the radar on top of the canopy with a M60 on a pipe mount.  The canopy was reinforced with plywood so that it would support the weight of the gunner.  The mid-ships single M60 mount was replaced with twin M60 mounts on some boats as well.

I have seen pictures of at least one PBR Mk II that mounted a 60mm mortar forward on a pipe mount on the starboard side just forward of the superstructure.

Like PT boats in WWII, crews modified the weapon mounts of the PBRs in order to get the best combination of boat performance and firepower.  I would suggest that you find pictures of a particular PBR Mk II and model it based on the pictures.  There are a number of Vietnam veteran sites that have collections of photos from the Sailors that crewed them. 

Matt Prager, SCPO, USN (ret)

Once in a while I see either one of the 40mm types mounted so the coxswain could fire it. I guess he was called a coxswain that's what I thought the Navy calls or called the guy who steers the boat.

I might have seen the 60mm mortar too as they were around a lot as well as was a few models of the 40mm grenade launcher.

I could see mounting a 20mm forward in the tub and maybe aft seems like a good place.

I noticed that the source that mentions the 20mm cannon is used for so many other articles about PBRs. I think they just copied it verbatim and did not check it out. One person says it and everybody just copies it.

My thoughts are that maybe one boat tried one and quickly went back to a 50 cal. so there are no pictures of it. I have read so many bad things about the 20mm guns the Navy used, even severely injuring the person firing them.

OK.......bought a  bunch of books off Amazon and scoured the internet.

There are NO pictures of any PBR either marks with a 20mm cannon of any kind.

My best guess would be at one time one or two crews tried them and replaced them with the 50 cals because of the issues with the 20mm cannons.

I have read a lot about the battles and many times you needed a weapon with a shorter max range as not to shot up a village on the other side of the banks. The best weapons for the riverine warfare was the 50 cal, M60, M79 and the 40mm auto grenade launchers along with personal weapons, maybe the 60mm mortar too especially for illumination. Anything else was overkill on Sampans and other small boats as well as the places they hid which need to be cleared out. Fire was best unless you had those huge weird vehicles that just tore everything up and buried things under their weight.

I even saw pictures of guys using a flaming arrow and bow. But NO 20mm cannons........I won't stop looking though.

The NASTYs in Nam were US built copies.  Built by TRUMPY from Annapolis.

I think I came up with why the confusion about the PBR boats. The PBMKIII had a 20mm gun mounted midship. I think that's were the confusion came from because they mention mounting the 20mm midship on a PBR. That is IMPOSSIBLE, that is were the coxswain is steering the boat no where to mount a big 20mm cannon.

http://www.warboats.org/images/jpg/GrayNov08/Graysbu13/13guns.JPG

That's a picture of the boat with the 20mm. i think one writer who was not familiar with these ships wrote something and everybody just copied it without question.

The mount needed to be connected something heavy like a deck made of metal NOT fiberglass. It's a very powerful heavy weapon and I really doubt it could even be mounted on a smallish PBR.

Um, that photo is not of a PBR ... It is a 65 foot aluminum PB MK V  from the mid to late 1970s, they're still used now in the SBS ...

That gun is not  a 20mm - it's a 25mm Bushmaster.

Well duh that's what I said it's a PB MKII....not a PBR and they had 20mm cannons in that position. The caption was wrong then, you're right it does have a 25mm looking closer that means it's the MKV and the 81mm mortar not the 40mm bofors.

They also might have been confused with Alpha boats they also had a 20mm midship.

BTW those MkII and MKV served after the war.

Just so much mis-information about Vietnam era ordnance.

The picture you provided is a PB MK III (there wasn't a PB MK V) and the midships gunmount is a 20mm Mk16 Mod 5, not a 25mm bushmaster.  The 68' PB MK IV had a 25mm M242 mounted on the fo'c'sle.

Matt

It does look like a bushmaster a bit......I'm not familiar with Naval stuff, I'm learning and only really interested in Vietnam era anyway. The point is that it's possible that's were the confusion came from. The only Bushy I ever saw was in a turret of a Bradley at Ft. Knox.

Thanks for the correct information and clarification.

Like I said the 20mm cannon on a PBR is bogus. The writer saw a PBMKIII or Alpha boat and mistook it for a PBR and now every writer that mentions the PBR says they mounted the 20mm at times.

What's the old saying about a lie living forever?