ice diving harness question

[grumpie]

Good Evening, we normally dive one diver down, the teather line has comm-wire in it and the tender is talking and listening to the diver. there is a back up diver all geared up and read to go if a problem comes up.  There is 90% diver also ready to go if need be. there is a lot of redundancy in what we do. We did a job on lake minnetonka where had almost 6,000 of rope out and about 6 tenders.
grumpie........