modified Robbe XXI with air system

[Antoine]

I am posting this for a friend ]http://perso.wanadoo.fr/antoine.lenormand/Images/festo1.jpg[/img]



Thanks for him.

[redboat219]

Hi AntoineL,
Try to get

Hi AntoineL,
Try to get a copy of Simply Submarines. There's a very helpful diagram of a Type XXI with an air operated ballast system.

Redboat

[Antoine]

thanks ! we will check

thanks ! we will check !

[liftmys10]

That looks pretty sweeeet!! Sorry

That looks pretty sweeeet!! Sorry cant help you on the install but i would like to folow up on that. Take lots of pics!

Thanks,
ShAwn

[k225]

Has anyone seen any articles

Has anyone seen any articles on installing an Engel piston tank in the Robbe Type XXI. I've seen photos but nothing written up on this mod.
Steve

[tabledancer]

I would like to see

I would like to see some info on this conversion also .

[Guest]

Regarding Engel tanks- I don't

Regarding Engel tanks- I don't know what the displacemnt of the Robbe boat is, but I'd guesstimate it's at least 1 litre, possibly more- she's a big ol' barge.

Bearing that in mind, a custom engel tank would be required if using a single tank, or the use of twin tanks.

If the latter were proportionally controlled using Markus Reiger boards, then you would have a VERY nice static diver with built in longitudinal trim control alongside depth control.

Andy

[k225]

I have a 750 ml

I have a 750 ml tank and was concerned it might be too small. Would it be possible to modify the tank to handle a litre?
Another option might be to use additional ballast weight, it would sit lower in the water though.

[Guest]

Yes you can modify the

Yes you can modify the tank- you'll need a longer thread, tie bars and tube.

If you lack the facilities, or skill to DIY, then I'm pretty sure Engel will convert it for you, and it'll probably be a lot cheaper than purchasing a new tank.

Andy

[k225]

Thanks Andy will follow up

Thanks Andy will follow up on this. Sorry to but in Antoine, thought it might be linked to my issue on the Type XXI.

[tsenecal]

robbe sells three sizes of

robbe sells three sizes of tanks

500ml
750ml
825ml

perhaps the 825 will do off the shelf...

or two of the 500

[subcom#2021]

Anton,
I guess that system

Anton,
I guess that system works as below;

[Ballast tank]=[Solenoid (blow) valve]=[Air bottle]=[1 way valve]=[Compressor]=

*Compressor sends pressurized air to large bottle while the sub is surface. You need to add trick to prevent compressor from sucking water (i.e. bend top end of vertical inlet to U-shape)

*Compressor will be automatically turned off when air pressure in the bottle reaches preset value.
(I guess kit contains pressure limit switch or pop-off valve)

Now large bottle is pressurized and works like propel gas reserve bottle.

Have you searched FESTO's website?

[redboat219]

Hi Antoine,
The air compressor

Hi Antoine,
The air compressor ballast system featured in Simply Submarines is actually 2 systems and they works like this...

System 1 (High Pressure System)

Air bottle (charged on shore)--> one way valve-->
ballast tank.

Sytem 2 (Low Pressure System)

Induction head--> air compressor --> one way
valve --> ballast tank.

You use the HP air to surface the boat to periscope depth then use the LP system to completely blow the ballast tanks.