The Hull Bottom Atoll is a shallow sea area east of Ivagor. During storms, this area is given a wide berth. Testament of what happens when you are blown into this area or blindly sail into it are scattered across the atoll. Hundreds of wrecks and sunken hulks litter the reef. Though dangerous for large ships, smaller ones can always be found in the area. They are fishing boats out of the atoll's villages and some brought in from Ivagor's larger settlements. Some of these wrecks serve as the abodes of scrag, sahuagin, and other aquatics that when it comes to feeding, they see no difference between humanoid swimmers and fish.
In the Black Tide War (1465 - 1504), forces under Admiral Jairall built strongholds in this area. These were raised quickly with magic. As part of his Sea Fern Strategy, they were built to threaten the ocean supply lines between Ivory Asylum to the coastal ports of the Farinteen Empire. If they gained naval supremacy the next objective was to capture Ulpa. All of this ended up being a waste of time and resources. Jairall's forces could not gain naval supremacy over the atoll and the wide sea-lanes around it. Most of these are ruins, worn badly from the waves and lack of upkeep. Those that are not are the abodes of fishers, or a tower or keep for a wealthy personage or trade company, lair of a sea hag or other monster, or perhaps a pirate's den.