Bouyancy is based on how much water is displaced, not amount of air inside the container. 66x12x13=10,296 cubic inches. Fresh water density is about 0.0361 lb/in^3 so that case has to displace at least 372 lb to sink.
Metric would be better for this but we’re talking about a stinger missile here.
If it’s filled with stuff then it’s not filled with air. So it would be less buoyant. But yeah, probably harder to sink than people would guess
Bouyancy is based on how much water is displaced, not amount of air inside the container. 66x12x13=10,296 cubic inches. Fresh water density is about 0.0361 lb/in^3 so that case has to displace at least 372 lb to sink.
Metric would be better for this but we’re talking about a stinger missile here.