First off you will need to obtain the Oracle of the Seas spyglass fisher quest reward. Double clicking the oracle of the seas spyglass will give you coordinates to the location of the Charybdis boss. Sail to the coordinates given the same as you would to a sos location. Apply bait to pole and fish it up, it may take several bait uses to get him up. I would not try this alone. A small group of 4-6 people with ranged attacks and the ability to crossheal is the simplest way to go. Bring along required supplies to fix your ship as it will get scuttled. In a previous post below or on page 2 of this forum I have included some pics of the battle. The charybdis bait seems to be a lot more common as opposed to the spyglass. Now you just need the spyglass and you are in business. Good Luck hope that helps!
The Albatross/ Lord Aphid LS