S 503 at B. Grognon ( Ile de Groix )

[jopaerya]

Looking for a good drawing of the S 503 at the M.K.B. Grognon , I have the drawing from the book Marine Flak Artillerie .
Is the batterie free to visit or is still a military area ??

Regards Jos

[Eax-E]

Hello Jos,
Free but burried whit sand through turrets holes.
Regards

[jopaerya]

It's a pity, but it's good conservation, do you know if there are French drawings of these bunkers ??
The internal bunker looks good on the drawing but the walls and roof not .

Regards Jos

[jopaerya]

Here you can see the Bruno and Ceasar turrets were +/- 2.60 m longer then the A and D turrets .

Drawing = Geschutzkunde Band 1

Regards Jos

[jopaerya]

Thr drawing from the book Marine-Flak-Artillerie

[jopaerya]

Are there any sharp arial photo's of this battery with the turrets on top of the bunkers ?? ( Nara )

Regards Jos

[Jihem]

I've got this one :

Gx322.JPG

[Jihem]

From the booklet « Seydlitz Ile de Groix 144 » (Jean Humeau & Gil Van Meeuwen - 1995) :

A.JPG

B.JPG

C.JPG

[jopaerya]

Merci Jacques

Looks the tip of the barrel is on the same length as the bunker, so we can estimate the thickniss of the bunker wall .

Regards Jos

[Eax-E]

It's a pity, but it's good conservation, do you know if there are French drawings of these bunkers ??
The internal bunker looks good on the drawing but the walls and roof not .

Regards Jos

Jos,

AFAIK no french service drawings. Hopefully our friend Alain took some measurements in 1983 (no highs, referring to your remark about the roof).

Regards

[jopaerya]

Thanks Arthur

[wimve]

Hi all,

Looking at the drawings I notice some things:
The drawings from the book (with bunker) show exactly the same (lower D) turret as shown in the book "Geschützkunde", with the two turrets.

The bunker drawings doesn't take in account the access of the two most important decks: the "Kartusche" and "Geschoss", the lower two decks.
In the ship configuration there are four decks, the upper two are boxed in with a round inner "tube", the two lower decks are not enclosed. In the bunker drawing at least the lower decks are not accessible.

Also there doesn't seem to be a floor in the turret pit.

[Eax-E]

Hi Wim,

The drawing of the turret comes from a 1/100 scale of the gun from the french army, not scanned from the books you quoted.

I also think the outer side of the drawing is not correct because as the bunker is an was already underneath when Alain visited it, he could not measure the thickness of the walls. Roof neither probably. If you looks closely, the turrey high is compressed and i'm pretty sure that if we had the right roof thickness it would fit.

Regards

[wimve]

Hello,

What I mean is that these two are from the same origin.

axis vergelijk.jpg

Anybody can "photoshop" a gun turret inside a bunker, or a bunker around a gun turret but what is real ?
I can draw any roof thickness with a bunker and turret that fits. But is this then the reality ?

[AvB]

We can clearly see the plans of Chazette are basic one, to give an impression. Up till now there are no precise plans.