Public Wifi
The following diagram shows how to connect to a public wifi hotspot but still keep your Meet LAN private and performing well. Whether the Internet Connection is satisfactory will depend on the number of people connected to the hotspot.
You should then configure the diving LAN on a different subnet (shown below as 192.168.101) but which is fully under your control. If you are using a router you can probably use its DHCP normally, except that you should set the Gateway address to the diving IP address of the 'Gateway' laptop (shown below as 192.168.101.15) instead of the usual default of the router's address. Be sure to run all the DiveRecorder software on the diving subnet (not the wifi one).
If you prefer not to use DHCP or even a router, you can use a switch or hub together with static addressing and be sure to assign the 'correct' Gateway address to each of the diving laptops so that they can find the Internet Connection.
Of course you could connect all the laptops to the wifi hotspot or wifi LAN and do away with all the cables, but then you run the risk of the network grinding to a halt at a busy venue and your Meet is open to the public. Not recommended! 