You need to get the Starite without setting off the naval mines above it, because they will explode and destroy the starite. There is also the matter of the robot shark.

1. Put a MAGNETIC FISH below and to the right of the small bomb next the starite. This should pull the bomb over into the water where it will sink. Put an INDESTRUCTIBLE IMMOVABLE GATE (WOOD) next to the spiked balls. Put an IMMOVABLE LARGE AIR VENT below the naval mines. They should explode without destroying the starite. Put a BATTERY to the right of the shark to kill it. Put a SCUBA on Maxwell and have him swim down to the starite.
2. Put a DEATH in the water and wait for him to kill the shark. Give death a MAGNET and put him in the area below the middle of the spiked balls. Let death swim around, luring the naval mines away. After the spiked balls fall in, give Maxwell an OXYGEN TANK and have him swim down to the starite. Use a MAGNET to move the bomb, and give him a SHOVEL if he can't reach the starite.
3. Put a HERO into the water and wait for him to kill the shark. Give the hero a VACUUM and put him to the right of the top naval mine. Wait for him to slowly lure the mine away and then let it explode on him. If the vacuum is destroyed, just give the hero another. Then have the hero lure the lower naval mine away the same way, exploding it when it is safe. Give Maxwell an AIR TANK and give him the vacuum. Have him go down to the Starite. Use the vacuum to pull away the bomb, and the spiked balls if they are down there.