Truth is, they generally produce better when you coax them along the bottom, taking time to seek out every little nook and cranny. My outfit of choice has become the Shimano Calcutta 250, on a Crucial CU-70MLA rod. Fibreglass has been the choice material for crankin' rods due to its forgiving nature. However, the slower action of a lighter rod will help compensate. Slow action rods will also help keep pressure on a fighting fish without applying real muscle which could tear the bait free.
Line is also a critical factor that requires close attention.
Due to its toughness, Berkley Big Game is a great crankin' line. Although it may feel a bit stiffer than conventional lines, its castability is not affected as most deep divers are fairly heavy and will cast with ease. Keep your rod horizontal or even pointing down and slightly towards the fish. If he decides to run towards you, the slack line can be taken out with a quick sweep. This positioning, while winding steadily and calmly, will allow you to boat most takers.