Who's Neptune Perkins?

Who's This? A minor underwater(-ish) hero from the Golden Age, who nevertheless got a full entry on page 22 of Who's Who vol.16.

The facts: Neptune Perkins first appeared in a Hawkman story in Flash Comics #66 (1945) and teamed-up with Carter Hall once more in Flash Comics #81 (1947). That's pretty much it until Roy Thomas dug him up and used him a couple times in All-Squadron in the early 80s, and then made him a core member of the Young All-Stars, taking Aquaman's Golden Age spot after Crisis erased the yellow-gloved King of the Seven Seas during the Crisis.
How you could have heard of him: As a Young All-Star, his origins were retconned to make him the mutant son of the real-life Captain Nemo who had forced aliens to make him a high-tech submarine. The man eventually changed his name to Perkins and married a Titanic survivor. I guess Neptune literally had the sea in his genes. Neptune Perkins would actually appear a fair number of times in the contemporary DC Universe, first in some issues of Peter David's Aquaman as the father of a new character called Deep Blue, and then having become a U.S. senator, a member of the committee monitoring Young Justice. He was killed in action in Infinity Crisis #3. So yes, he appeared quite a bit, but as with most Golden Age heroes, I'm really interested in what they were like BACK THEN.
Example story: "The Dweller in the Sea" by Gardner Fox and Joe Kubert, from Flash Comics #66 (1945)

For some reason, I always thought Neptune Perkins had his own, short-lived strip. After all, outside the Justice Society, it was rare for superheroes to meet and team up back in the Golden Age. But no. In both his Golden Age appearances, he featured in a Hawkman story, and the Winged Wonder is obviously the star; Perkins part ally, part damsel in distress. The Who's Who entry also makes it seem like Neptune is an underwater hero like Aquaman. Again that's wrong. He lives on a boat and though he must swim a lot, he's definitely an air breather. As his origin makes clear:

But what about high blood pressure?! Anyway, his parents raise him on a boat and he grows up be a strong swimmer with webbed hands and toes, and... a best-selling author!

Oh look, he's got a seagull for a pet. That becomes important later - you do remember who's strip this actually is, right? - but before we get to that, we cut to a nearby town where Dick Tracy-type crooks are talking about their next bank robbery. They're led by "Rice" Ryan, a man decidedly obsessed with that particular staple.

See the plan is simple. Steal Perkins' boat, fill it with rice for the journey to some country without an extradition treaty with the U.S., rob a bank, and escape with the money. And they do trick Neptune, except his wounded gull escapes...

That's right, the gull has a chat with Hawkman's hawk sidekick Big Red and our (real) hero gets involved. He tries to help Perkins steal his boat back, but the crooks are armed and dangerous, and they capture the kid. Hawkman decides to follow one of the crooks to shore, which leads him to the bank robbery in progress. Unfortunately, he's a bit of a klutz.

Hawkman slipped on some rice. Because 1) Rice carries pocketfuls of the stuff uncooked to snack on, and 2) Carter kind of forgets he can fly. While he's knocked out, they escape, so he only catches up to them when they're underway on some rough seas. A wave makes him bump his head again (is he the Golden Age's answer to Hal Jordan?) and the crooks throw him in the hold with Perkins. But don't worry, he has a plan. He takes a crankshaft from a toolbox and starts drilling a hole at the bottom of the ship.

He's not trying to sink the boat. Instead, we see the hull rupture violently, leaving the bound heroes free to cut their ropes on sharp seashells.

So how did Hawkman do it, kids? Did you figure it out? The short of it is: SCIENCE!

That's right, what little water got in the hold blew the rice up to destructive size. Thank you Neptune Perkins for being there to ask the question for us. As for Rice Ryan, he swore off rice forever. The end. Well, almost. Neptune would return in an adventure involving this same duo traveling to Venus in a light bulb.

I wouldn't lie about that.

Who else? Between Mysto and Neptune Perkins, the only other possibility might have been Nemesis, someone I'd never heard of at the time, if only he hadn't soon become much more prominent thanks to the Suicide Squad, and later as Wonder Woman's boyfriend. Up next, one last hero from volume 16?