Once you have finished Deep Sea Troubles you can speak to RuneScape gold Gompar for another one called Shipwreck. Gompar will inform you a ship has sunk when it crashed into the walls of Mogrin. He'll want you to repair the wall. Go up to Captain Murk and tell him to sail closer to the wallsocket. He will do so. You may then dip.
You will still be in the surface of the sea. To repair the wall, you must have a hammer, 23 Gomrock Bars (could be bought in Mogrin in any area or mined outside with 43 mining and smelted in an underwater port, not a furnace, with level 51 smithing) and level 37 structure. Repair the wall. Return up to Captain Murk and let him sail a little further away so that you can dip. He'll do that. Go to the palace (can be entered through some region) and speak to Gompar.
Tell Gompar you mended the wall. He will thank you and give you 16,000 gp. Tell him you believe the boat belonged to a captain that was sailing this manner. He will say that he saw a few human beings float to a nearby cave at a water cliff but it caved in due to a little earthquake. Go inside the cave and it will be dry in there since the water can't reach far enough to flood it.
There will be 3 individuals sitting back on the cave walls, Captain Lockbard, Drew and Cabin Boy Jeremy. Talk to Captain Lockbard and he'll thank you for discovering him. He will give you 3 classic lamps he found in the cave. A cutscene will happen revealing you attracting the 3 individuals up to the boat with the assistance of the Breathing Orb. Congratulations, quest complete! The rewards include 8,000 prayer XP, 11,000 smithing and mining XP, 9,000 construction XP and the ability to get fish summoning pets.
To find fish pets you have to have level 73 summoning. Find fish eggs in underwater caves or elsewhere, (should have level 73 summoning) if you discover a shark pup, then buy OSRS gold you are very fortunate. If you take over 1 egg you can only get one fish.
