Hi Donald, Yes the compression of the air in the tank can be a bit of a problem. But does not really impact the problem I'm trying to solve just now. At the depths I tend to use the sub at (no more than 6-8 feet max, any deeper and you tend to have R/C problems). It is not really a big deal (since the dynamic control from the planes etc. can easily deal with it). However it can be an issue if you go too deep since like a real sub you may not have enough pressure to blow the tank! Andy ----- Original Message ----- From: "Donald L Burdette" To: Sent: Saturday, October 21, 2000 5:55 AM Subject: Re: [EE]: Help water level > Andy - > > Someone suggested closing the inlet to your ballast tank, and that got me > thinking. If you have air in the ballast tank, and the tank is open to > the outside water, then whenever you dive, the air will be compressed and > you will take on more ballast water. > > Is this a problem? Do you need an active ballasting system that will > constantly adjust the ballast level? Would it be easier to close some > intake valves and ensure that once you reach neutral bouyancy, you stay > there? > > Don > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. > > > > -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu