MikeFerrara:For those who haven't dived this way I'll add though that you can't count on having good vis through the whole dive no matter how good it is. You need to have a safety reel/spool and know how to use it. If that's not the case then you should have a teather like most ice divers use.
The bottom is solid rocks mostly.. viz cant really go bad even then you cant miss the only opening of light coming in
But i do agree with you that you could and should run a line down to the plane
And we do always carry a reel and some spools