Could a modern navy replace skilled sailors after mass casualties?

With modern weapons and ships so technically demanding, could most countries replace sailors after a mass-casualty event?

Only to the extent that they have mitigated concentrated losses and maintained enough trained reserves for the particular scale of casualties.

The technical demands placed on modern sailors make the scale of a casualty event important to any replacement calculation. Prevention and mitigation receive attention before replacement begins. The depth of available reserves is another condition. Their place within the full force structure determines how useful those reserves can be when losses occur. No general replacement timetable is given for all navies.