I have been constructing this Nautilus build for some time now after I realized that Nautilus can be considered a Juggernaut. He's short-ranged and slow enough to be kited for days. The only thing that he doesn't have is enough damage to actually win a duel. What do you guys think?
Starting Items (Usually)
Core (Trinity Force or Iceborn Gauntlet or Black Cleaver choice)
Additional (Titanic Hydra or Ravenous Hydra)
Situational
Never mind the downvote fairy. They just mad cuz you're going off meta. Have an upvote for creativity :)
I call it... JuggerNautilus Good build BTW!
Would a 
work? The tenacity goes nicely with the merc treads and cdr and movement speed isn't exactly bad on Nautilus either
stop stacking unique passives.
I've done juggernaut Naut before and its good. However you are going way too overboard with the stacked passives. Triforce is all the damage you ever need from an AD item. The other damage items you need all come from your tankiness.
Interesting. Naut isn't easily kited, considering he's got four different kinds of cc built right into his kit (hook, snare, slow, knockup). So if you choose to build him like a juggernaut, he should be able to wrangle in and stick to targets pretty easily. However, I've got some issues with your items.
only stacks it's cleave passive on physical damage, and without a ton of AS, Naut isn't going to be able to stack it efficiently. If Naut's W's DoT was physical damage I'd say you were onto something.
is still a good item on Naut, but it was better back before you could spam his E. Now that Naut can keep the slows coming on an almost constant basis, the slowing field on the frozen fist isn't as helpful as it could be. The stats are still good, but has similar stats and Naut can stick to people to make it's aura work harder. Not a mistake to build IBG, however.
is what I'd recommend out of the three. The only stat you could argue that goes to "waste" here is the crit, everything else Naut really likes. Even the AS bonus is great since that anchor is so slow. It also gives the rage passive without having to build a Cleaver; best of both worlds.
I would also argue that > for juggernaut Naut. (JuggerNautilus?) Naut's W shield scales with HP, which will probably provide more damage mitigation than the lifesteal of the Ravenous would. is a natural fit; anything that helps Naut get around quicker is a godsend for him.
While Naut's base AD is nothing special, (and optionally as well) combined with your W shield basically makes you into a ghetto 
.
I'm going to try out JuggerNaut. It seems fun. Good post.
By Riot's Definition, Nautilus is a tank, not a Juggernaut. While both are typically (but not always for tanks) slow and kitable, the big difference here is why they build tanky.
A juggernaut will build tanky so they can be the front line and output damage.
A tank will build tanky so they can be the front line and peel/CC for their damage dealers.
Notice the difference? A juggernaut would build damage if they could survive with that, but they can't, so they typically get one damage item, then tank so they can be a high damage, low CC front line for their team.
A tank doesn't do nearly the damage of a Juggernaut, but exchanges that for much stronger CC and teamfight power. They don't build tanky to directly support themselves, they build tanky so they can be a better disruption for their teammates to do damage.
Naut has so much CC, and so comparatively little innate damage, that he is absolutely a Tank, and not a Juggernaut. Sure, you can force him into a Juggernaut role, but then he ends up too squishy, and limited (unless he's snowballed of course).
Don't worry, CertainlyT will fix the "Nautilus isn't a jug" scenario for you :D
Any kind of fighter Nautilus automatically wouldn't be considered a juggernaut because he still has the gapcloser on dredge line to bring him to his target and 3 other forms of CC that make him fairly difficult to kite, but I see what you are trying to do. You want a bruiser-oriented Nautilus build that gives him both tankiness and damage. That idea can work, but it needs to be done right.
Iceborn Gauntlet is bad on Nautilus because he already has enough CC to not need the CC portion on the passive, and the passive doesn't do enough damage to make it worth using over Trinity Force. Black Cleaver is bad because Naut's only form of physical damage is on his basic attacks (including passive). Trinity Force is the best of those options, but is still not ideal because he doesn't get enough out of it. This leaves your core items with little value compared to other alternatives.
Ravenous Hydra is not good because of Naut's lack of AD scalings and his low attack speed. Sterak's Gage might be good, but only if Nautilus gets enough out of the % base AD with his basic attacks (including Trinity Force), because that's all it's useful for. Dead Man's Plate isn't ideal on Nautilus because he does have a gapcloser, and other tank items might be better.
Of all the items you mentioned, Ravenous Hydra might just be the best offensive option of the ones you listed because Nautilus likes to build a fair bit of health due to wanting tank stats and having the health ratio on his W, but at the same time he still has the attack speed problem that plagues Ravenous Hydra as an item on Nautilus, where he can't proc the passive too much due to Naut's low attack speed.
However, there are some offensive options that might be worth considering. Wit's End has good synergy with Naut's kit due to increasing the magic damage he deals on his WE while also buffing his tankiness, while Zephyr might be another good option to consider considering it has really good stats if you decide to build AD but also don't build too much crit, which isn't good on a bruiser. Build full tank after either and you should be fine.
I have a buddy who loves to do it, and before the recent nerfs Naut was an even better Jug. and it was hilarious to see him dominate top lane with him. The most common items I saw in his build:
or 
Wits end was typically his first item and it was just freaking hilarious.
