Discovery: IXC U-boat Turm IV upper platforms have different widths

[AndrewTSM]

I have found out that the turm IV upper wintergartens come in 2 different widths. Due to catching details that are on photo's like these.


As you can see there is no conical support and the winter garden merges perfectly with that triangular edge, whilst boats like U-505 have a conical support due to the wider platform which needs more support and that the upper portion of the wintergarten flails out a bit and doesn't go in one straight edge.


The wider platforms have 56 planks going across and the the latter 50, I believe the platforms were widened for more clearance of the flak38's rotation.

[dougie47]

Hello Andrew,

I don't have data on the width / gap size of the planks. But I do know that the slotted deck was a standardised width on Type IIs, IXs and VIIs. Counting the number of planks to establish turm width only works if there was a standardised width / gap size on late war towers. That has to be established first. Simon (NZSnowman) is the guy to ask - try sending him a PM. My guess is that the plank width and gap were probably standardised.

There does look a difference in those photos. The third photo (of U 515) shows a ladder and there is a horizontal stanchion missing; this allowed a crewman to climb up the ladder and then through the gap in the tower railings. There is also the mesh on U 505 and U 515 but not on U 190.

The conical part was there on some boats but not on others (same with VIICs). For example it was not on U 869 but was there on both U 880 and U 889. All these are IXC/40s from A G Weser in Bremen so it was not shipyard specific.

Given what we know in general about U-boat modifications and how they were not mass produced as identical items, we should expect the general arrangements of the Turm IV to be the same but that there would be slight differences in the specific details within these towers. Therefore a variation in width of Turm IVs does seem very possible.

Cheers,

Dougie

[AndrewTSM]

Every boat that appears to not have the wider platform don't have that conical support, which says something, I've checked many photos.

[AndrewTSM]

The width of the planks are indeed standardized looking at a lot the photos, most IX U-boats have the same number of planks at the bottom platform. 30 at the thin section and 37 for the M42U platform. which would probably go for the top aswell.

[dougie47]

Hello Andrew,

If those which do stick out have the conical support, and all those who don't stick out don't have the support, this would make sense. The wider platforms would need the conical support as they were wider and therefore needed additional support from underneath.

If you are able to study Type VIICs it would be interesting to determine if a similar correlation exists between the conical support and wider platform. This would further support the hypothesis.

Cheers,

Dougie

[AndrewTSM]

I've begun making the replacement for my model which has the narrow platform.

[AndrewTSM]

Here is more visual support for my claim.

Existing U-boat with the early platforms were upgraded to have wider platforms, I think it gives the AA gunners

room.