M18 Tank Destroyer versus Kriegsmarine "Flak Boat" Brittany August 28, 1944

[PT Dockyard]

Hello all!

A mystery about a possible rare battle between a US Armuy armored vehicle and a Kriegsmarine ship!

In the book "1944: Americans in Brittany-The Battle for Brest" there is mention on page 33 of the following:

On August 28, "Bataan"(an M-18 Tank Destroyer) was at the village of Concarneau and came under fire from a flak ship roughly 5000 yards offshore. With only six rounds "Bataan" hit the small ship. The local German garrison surrendered saying "any weapon that can sink a boat three miles offshore is too much for us."

From the timing and location I would think this possibly was a Hafenschutzboot or Vorpostenboot from Lorient. Does anyone know of any record of this engagement? A few hits from a 76mm gun causing the craft to sink makes me think it was pretty small, if it was hit at all.

Thanks,
Dave G.

[Urs Heßling]

hi,

"Flak ship" was the term the Ruyal and US Navy used for the German "Vorpostenboot"

On August 28, 1944, however, AFAIK; there wasn`t a boat of that size left on the coast of Biscay. British surface ship and aircraft had swept all ships from destroyer size down to Vorposten- and minesweeping boats away.
Thus, yes, it was quite probably a small craft (IF that story is true at all)

greetings, Urs

[PT Dockyard]

I am thinking at best, if this happened, it was a small Hafenschutzboot, probably from the Lorient HSF. The M-18 had very thin armor (13mm) and anything larger than rifle fire was considered a threat.

Any account like this I read with a skeptical eye. I am always interested to read of engagements between KM vessels and the Western Allied ground forces.

Dave

[Urs Heßling]

hi, Dave,

Any account like this I read with a skeptical eye.

I wonder whether the M 18`s gunsight worked at 5000 yds when the normal fighting distance against tanks in the Western European theatre would be - my guess- something like 500 yds

Any account like this I read with a skeptical eye. I am always interested to read of engagements between KM vessels and the Western Allied ground forces.

Schnellboot S 184 sunky by British coastal artillery off Calais, see
https://www.historisches-marinearchiv.de/projekte/s_boote/lebenslauf_boot.php?where_value=169  (well, that was not really an "engagement")

greetings, Urs

[PT Dockyard]

I wonder whether the M 18`s gunsight worked at 5000 yds when the normal fighting distance against tanks in the Western European theatre would be - my guess- something like 500 yds

It would be at the high end but yes. Also consider the relative size of a small patrol craft (15-18m long or so) compared to the M-18's usual target of a tank.  The boat would be like hitting a house-  easy for a high velocity
flat trajectory gun like the 76mm the M-18 carried.

Dave

[Urs Heßling]

hi, Dave,

we`re getting a little bit off course, but ... I tend to disagree.

easy for a high velocity flat trajectory gun like the 76mm the M-18 carried.

The M-18`s M1A1 gun had a muzzle velocity of (max) 820 m/s.

The Bofors 40 mm aboard the fast patrol boat under my command had a muzzle velocity of 1020 m/s, and I remember quite clearly that you could observe a "ballistic" arc (rising and descending of the projectile) when firing on a surface exercise target at a distance of 6000 m.

greetings, Urs

[PT Dockyard]

Well, given I have not fired anything larger that a rifle I cannot offer any actual experiential data. My post on range was based on much reading about US armor engagements when I am not researching coastal craft.

Anyway, I looked through my Groener's V.8 and started checking the fates of the Brest and St. Nazaire HSF craft looking for one that mentions gunfire. Maybe this happened, maybe not. None of us were there to say for sure.

Dave G

[Knouterer2]

US higher commanders had some doubts about the M18 (thin armour, awkward loading) and only three of the nineteen TD battalions in the initial landing forces were equipped with it.  The 603d, 704th, and 705th of Lieutenant General George S. Patton's Third Army all came ashore in Normandy by late July 1944.

From the unit history of the 603rd (B Company, period 15-31 Aug.) (http://www.tankdestroyer.net/images/stories/ArticlePDFs/603rd-UH_1944.pdf):

"Third platoon formed part of a small force sent to
capture Concarneau . Direct fire was placed on the
town and 1 - 20 mm flak boat was destroyed. 180 rounds
were fired indirect on gun position and fortifications
at Concarneau."

The report does not say whether the boat in question was moored or actually at sea.

[Darius]

Page 11 of this document calls the vessel "1 AA Flak-boat".
May be a Hafenschutzboot?



Darius