On board ships, what was 'hard tack'?

The racehorse Seabiscuit's father was named Hard Tack. Hence, sea biscuit.

Cruise food is so much more upscale now !

Biscuits that are HARD is better than NO biscuits. On long voyages/trips, you don't have the luxury of popping into your local Fast Food joint to eat. Just dunk it in a liquid, it'll soften up.

If they are baked four times, does that make them "bi-biscuits," or "quadcuits"? Since biscuit gets its name from "twice-cooked."

Hard tack and weevils. Remember, always choose the lesser of two weevils.

Player #62086564, sometimes you get them in c-rations. I broke a couple of teeth when I was a teenager on hardtack. In the Navy, we call them pilot biscuits.

I got the answer right because of an Andy Griffith episode

It's still used in many traditional Newfoundland recipes, the most common being fish and brewis.

If you know Max Miller on YT you'll definitely know what hard tack is