I got up to almost a rank of 400 and I could no longer get any loot so I fell back below 200. I have to consciously lose battles every now and then so I dont get to high. Just getting the resources almost guarantees a win a majority of the time for me.
Same thing happens to me. I recently improved my base and I feel like it might be a mistake. My rank flew up 200pts. I'm considering going back to a base with a weakly guarded PH until I max. out my defenses. Last night I went to bed with less than 1k gold and 2.8MM grog, needing 2.0MM to train in the morning. I woke up with 750k... lost over 2MM (~75%) in less than 12hrs. I got attacked by the same person within 3hrs.
What worked for me was, design the base to have a strong side and a weak side, then strengthen the weak side by putting the pirate hall there. The strong side will have more/better walls/defenses, bunkers pointed that way, and so on. That way enemies have to choose between attacking the strong side, or attacking your pirate hall. At least if they do manage to snarf some resources by going through your pirate hall, you'll have a 12 hour shield to show for it. Of course don't make the weak side too weak (for example all bunkers facing away, plus no walls, plus weak defenses) or else you'll keep getting nearly three starred from that direction. But at least that would be better than losing all your resources multiple times before you get a shield. Another tip that I'm sure someone already said is to ditch your rank: start fighting and surrender multiple times before you log off. And spend all your resources. If you have few enough resources and low enough rank, you won't get attacked at all for 12+ hours at a time.
That's exactly what I did. Any time I was saving for something costing over 3M, I'd configure my base like @Neckbeard mentioned, then before quitting for the day, repeatedly attack/surrender to the no-loot stronghold north of your island. Much easier/faster than surrendering to other players. Plus it's free, and doesn't give those guys rank points they didn't earn. It worked so well, I left my town in that layout ever since. (part of that is being lazy about doing a needed redesign, pe-edit mode) If anyone's interested in the design specifics, search Tortuga Nest guild and my island is Kel