How long would it have taken for the people on yacht to die?

It’s such a tragic incident and I wanted to ask how long it would’ve taken for the victims to drown cos it seems like it could’ve been avoidable if proper alarms / safety practises were taken place.
If they were asleep then I guess they were unfortunate and didn’t wake up so drowned. But even so why wasn’t their an alarm sounded?
But if they were awake and in their cabins could they have got out of the yacht and swam into the sea quickly?
It seems such a shame, I guess the people on deck had the best chance of survival

The issue with this yacht appears to be the sudden catastrophic capsize and ingress of water into the vessel as the yacht went over. Assuming it was the weather that caused the capsize and no other third party involvement, the water would infill every space very quickly if hatches were left open. Swimming against this would be virtually impossible until the water pressures had equalised. It is impossible to say exactly how long it took for those poor unfortunate people to die. Even with extensive training there is a maximum amount of time that someone can hold their breath until oxygen starvation causes loss of consciousness and later death. A lot of factors affect that. Alarms don't really help at all here. The captain and crew in charge of this vessel have a lot of questions to answer. The weather forecast was available to all and should have been heeded by mooring in a protected harbour. Who was left on watch? What was their experience and capability? Were all the boat hatches closed, if not why not? Was the captain ready with the engines started (to steer into the wind) Why was the yacht left in a vulnerable position broadside to the prevailing wind? I am sure the authorities will be looking into this tragedy as they did with the Costa Concordia.