Unknown Jap Navy fuze - plug firing representative dummy?

[Darkman]

This brass Jap Navy fuze is not threaded inside so I assume it is a plug firing rep.

It has a 47mm diameter and 20mm tall thread and is like a type 91 fuze. Overall dimensions are 63mm high and 53mm wide.
The only mark on the cap = "Ka".

Does anyone know for sure what type it is and the significance of the green paint?

Thanks, Graeme

 

[BOUGAINVILLE]

G'day Mate,

What you have is a dummy Type 5th Year IJN Projectile Fuze. These were used in much the same way as the IJA Bakelite transit plugs. These would take the place of the fuze during shipment and were only removed and replaced with a fuze and gaine just before use. The top of the brass dummy would've originally been painted black indicating it as a dummy fuze. These dummy fuzes were made of either brass, Bakelite or steel. They had a wooden dummy gaine inserted in the base and secured by a screw. This wooden gaine represented the genuine gaine and retained it's space within the moulded explosive in the projectile.

Now some projectiles such as the IJN 76mm HE could be used as either anti aircraft or as anti shipping. For this there was an adapter which enabled the 5th year fuze to be used for anti shipping. If the projectile was to be used for anti aircraft then the adapter would be removed and the IJA Type 89 Powder Time Fuze would be screwed in place in conjunction with the IJN Type 96 Gaine.

The green on your fuze adapter ring means that the projectile that it came from was explosive filled.

Below you can see some examples that I have of these dummy Type 5th Year Transit Fuzes complete with wooden gaines.

Hope this has been of help.

Cheers,
Robert

 

[Darkman]

Thanks for the comprehensive response Robert. Much appreciated.
Regards, Graeme

 

[BOUGAINVILLE]

Hi Graeme,

Had a phone call from Ron this evening. I got the impression that there was a wee bit of confusion about your photos. Just to make it clear that in the photos posted it is two different objects depicted and not just a dummy fuze. It is a dummy fuze and a fuze adapter. The fuze adapter which has green paint does not form part of the dummy fuze at all. The sole purpose of the adapter is to enable the projectile to be used with a choice of fuzes with in a range of two different sizes depending on operational requirements such as AA configuration or anti shipping etc. In this case the adapter is kept in place when a 5th year fuze is used and discarded if a type 89 powder time fuze or a similar sized fuze is used. Even though the type 89 powder time fuze was army in origin the Imperial Japanese Navy did use it in certain AA configurations. A good example being the 76mm HE projectile.

Even though one might think that your photos depicted a dummy type 91 mechanical time fuze, the fact is it doesn't at all. It is just a fuze adapter and a dummy 5th year fuze (minus the dummy wooden gaine).

Cheers,
Robert

 

[Darkman]

Hi Robert, yes there was a bit of confusion but I didn't know how to explain the things Ron didn't understand. I'm glad you were able to put him straight - or do I have to pass this on to him? Cheers, Graeme.

 

[BOUGAINVILLE]

Hi Robert, yes there was a bit of confusion but I didn't know how to explain the things Ron didn't understand. I'm glad you were able to put him straight - or do I have to pass this on to him? Cheers, Graeme.

Yes Graeme I would appreciate it if you could explain to him as it will be better with you being there than trying to explain long distance. I you need any additional information or ways of explaining things just let me know.

Another point is that the adapter is painted green for explosive filled because it is part of the projectile compared to the dummy fuze. The dummy fuzes were black to indicate a dummy fuze. This can't be seen on the example in the photos as it has obviously been cleaned off. My brass examples all have remnants of black on the top portions above the spanner flats. Therefore if the adapter was part of the fuze it wouldn't be painted green but instead be black.

Maybe that explanation might help to clear any doubts or confusion.

Cheers,
Robert