Flooding tubes

[DavyJonesFootlocker]

I wonder why there is no time lapse for flooding tubes? How long does it take to flood one?

[Nisgeis]

Here'e the procedure for flooding a tube:

http://hnsa.org/doc/fleetsub/tubes/chap9.htm

It doesn't seem like it's a long job, but not that quick either, so probably a few minutes? Something you'd want to do shortly before firing. I believe captains tried to avoid having the tubes flooded for too long, as the pressure affected torpedoes badly.

[TheBlobThing]

Plus the flooded tubes might have given the diving officer a harder time maintaining the trim.

[DavyJonesFootlocker]

Good info and good to know. Thanks.

[Graafenstein]

Could it be that you generally want your torp doors closed due to a possible decrease of speed? (and lesser speed when going reverse with aft doors open)

Opening your torp doors will naturally release bubbles towards the surface, but is there a chance that the bubbles could be a give-away in calm seas?

[Nisgeis]

Originally Posted by TheBlobThing

Plus the flooded tubes might have given the diving officer a harder time maintaining the trim.

Tubes were flooded from a tank underneath the torpedo tubes, so the trim of the boat was not affected. Although tubes could be flooded from outside, most of the volume of the tube was taken up by the torpedo.

[Nisgeis]

Originally Posted by Graafenstein

Could it be that you generally want your torp doors closed due to a possible decrease of speed? (and lesser speed when going reverse with aft doors open)

I'm not 100% about that one, but most of the drag underwater was from the sail and the deck guns (more drag if they had plates on them). I don't think an outer door opening would induce too much drag, plus the stern tubes on some types were scallopped out and not flush with the hull, like the USS Puffer. I never paid much attention to whether the tubes were flush or not before.

Opening your torp doors will naturally release bubbles towards the surface, but is there a chance that the bubbles could be a give-away in calm seas?

Nice question Graafenstein! When the tube is flooded, it's vented into the submarine, so there shouldn't be a whole lot of air released when the doors were opened, though I remember vaguely that some air could be trapped at the top of the tube after pressure was balanced. I'm not aware of any submarine's position being compromised by the amount of air released on opening a door or firing a torpedo - anyone have any examples?

[TheBlobThing]

Originally Posted by Nisgeis

Tubes were flooded from a tank underneath the torpedo tubes, so the trim of the boat was not affected. Although tubes could be flooded from outside, most of the volume of the tube was taken up by the torpedo.

Nice info, thanks

[Mush Martin]

Just to add.....

Once the tube is flooded the torpedo is
on internal battery power and needs be fired
within I think ten minutes or maybe five.


M

[Nisgeis]

Originally Posted by Mush Martin

Just to add.....

Once the tube is flooded the torpedo is
on internal battery power and needs be fired
within I think ten minutes or maybe five.


M

Interesting, where's that info from? It's always interesting to find out new things. I've read accounts of torpedoes being fired after more than 20 minutes and having gone stupid as a result.

[Mush Martin]

I cant recall off of the top I will see if I can locate it amongst my
own stuff. Im sure its from the Bookshelf not the net.

M

[JackhammerJohn]

What is the advantage in opening the tube rather than just firing the torp?

[Zero Niner]

Originally Posted by JackhammerJohn

What is the advantage in opening the tube rather than just firing the torp?

When you your launch a torpedo without opening the tube, you waste a few seconds for the door to open before the torpedo launches.
This tends to mess up your firing solution, even if you use auto TDC.
So opening the door first makes for more accurate shooting.