That's where floatation does come in. When your hull is breached. I've seen an SV T-boned by another and though it was quickly pitted, it might not have stayed afloat had it not been able to continue on it's own power. I guess it comes down to investment risk. You can keep a boat dry, for the most part, but floatation is like insurance. I've never launched w/o a taped hatch, btw.