The conventional or trolling reel (or casting reel as it’s often called), is generally used in heavy deep-sea/big game offshore fishing. Whether trolling or bottom fishing for big game fish in the deep blue or just a deep lake, conventional reels are useful.
The important things to look for in a good trolling reel are heavy-duty graphite or machined aluminum construction, a smooth and powerful multi-disc drag system and a large line capacity to handle prolonged combat with bigger and more powerful fish. They have to not only be able to handle more fishing line, but they also have to be able to pack on heavier test lines.
Conventional reels come in either star or lever drag systems. Other features to look for in trolling/casting reels include a dual-speed reel, which lets you easily switch from fighting large, reel-smoking brutes like tuna and marlin to power-cranking up big fish from the bottom with the flick of a lever. A loud audible clicker will also come in handy so you can hear line being pulled over the engine noise.