After you've freed the Spirit of Wisdom, you will proceed to the Temple of the Ocean King. Navigate your way through this to uncover the location of the Spirit of Courage. Visit Mercay town and note the mailbox should be wiggling. The postman will descend and read a letter from Eddo, announcing the new Salvage Arm.
Head to Cannon Island and speak with Eddo. Be warned: he is going to ask you to shout to determine the price of the Salvage Arm. I've heard the prices range from 1,000 to 200 rupees.
You can either scream "Salvage Arm!" or snap your fingers or even blow or tap the mic.
Go to Cannon Island and buy it from Eddo. The price varies depending on how loud you blow/scream in the microphone. I recommend you blow into the mike, it's a lot less embarrassing.
Set the Grappling hook on your menu, then press the button you set it to.
No, you're stuck with that salvage arm.
You use the salvage arm.
You should get a letter Eddo and he will tell you to go to him to get a salvage arm
You can get the Salvage Arm from the man who sold you the Canon on Canon Island in the Southwestern sea chart region.
you go to the green spot and use the salvage arm
You can`t obtain the no excisting item, but you can use the salvage arm.
X marks the spot, then use your salvage arm.
Cannon island
get a salvage arm and go get the sun key then go to molida island and dig in front of a palm tree
There is no under water land, but there is the sun key in a box on the sea floor. You have to get the Salvage arm and get the box.
bosses and under the sea with grab arm
Go to the dock where you meet the pirate guy and talk to that big dude who customizes your ship- he will fix it for you.
You can get it from defeating bosses or getting it with the salvage alarm :D