In my 9 1/2 year circumnavigation, I was able to catch as many fish as I needed (tuna & dolphin) deep sea everywhere, except the Med (caught lots of plastic bags, though).
Never use a pole, as it is nearly impossible to get enough slack on a moving sailboat to reel in w/o tightening the drag too much.
Use a hand line of clothes line size line w/ about ten feet of shock cord tied to the boat (with the line having slack until shock cord is at full extension) as well as the line. A pair of leather gloves soaked in water helps. A quality roller bearing swivel at the lure end is absolutely necessary, to a multi-strand wire crimped leader (150# or so) 6 to 10 feet long to the lure (green & white {Atlantic} blue & white {Pacific or Indian}) 6" plastic squid w/ 1 oz (or so) egg sinker in the head or feathers w/ same weight head (I like the ones w/ the red glass eyes best).
Drag this line from the quarter not the stern (the quarter wake gives the lure more action & it's clear of the boat's turbulence).
The lure should be about twice the length of the boat @ 6 knots, more if faster (I have successfully caught fish as fast as 17 knots), less if slower (you'll get the hang of it quickly).
Remember, the fish are attracted by the boat deep sea, so keep your gear fairly close, but clear of the turbulence directly behind the boat.
Good luck & eat well.