You can motor mooch a cut plug and should be able to fish down to at least 100 ft, depending on the tides and currents where you will be fishing. I would start with about a 6 oz. sliding ball weight and move up towards 12 oz, depending on the tides. If you have a sounder, determine the depth. You can also get a good idea of the depth from the local charts or just stop the boat and let the weight down to the bottom, counting how many pulls it takes to get there. Reel back up 10 ft and put the boat in gear at slightly slower than trolling speed. Once your line has gotten to about a 45 degree angle, take the motor out of gear and let the line settle back dow again. Note though, you do not want your line to be at 90 degrees or your bait won't turn over.
Watch your rod tips as one of a few things will happen. The fish will hit hard and in this case it's game on, or, you'll just see a tap, tap on your rod tip. If this happens, they are usually just mouthing your bait. Let out 5 or 6 more pulls and see if he comes back. Lastly, you may see your rod straighten out like there's no weight on your line. If this happens pick up your rod and reel in like crazy. A fish has picked up your bait and is moving towards the surface. You need to catch up to him until you feel his weight on the backbone of the rod and then set the hook firmly. Works good for springs.
Or you can jig as someone else has mentioned too. Just match your lure to the predominant baitfish in your area. Also when jigging, don't use the same motion all the time, mix it up. A couple of short lifts (12-24"), a longer one (24-36"), a sort, two longs, etc.
Good luck,
George
Seafood, eat it, then catch more.