Downriggers are the most effective way of getting your lures down deep where the fish are. Some small clamp on models can be had for $40-60. Check Cabelas.com, Basspro.com, or boatersworld.com. These are excellent tools for getting you offerings down to where the fish are. If you fish for salmon or have a larger boat, I might invest in a Penn or a larger Scotty downrigger if $100-200 isn't an issue. These will be more effective for all around fishing.

The beauty of a downrigger is the ability to place your lure or bait where the fish are, and after the fish hits, you only have the fish and your lure to deal with. No flasher or popgear gets in the way, so you feel the fish. I would much rather catch 5 pound silvers on a plug cut herring off of a downrigger, than catch them off of a flasher combo.

Use this in combination with an accurate fishfinder and you increase your odds of catching fish exponentially.

Some folks also use lead core line, but in crowded bumperboat situations, it can be difficult to troll with 100'+ feet of line trailing behind you. If the lake isn't crowded, go ahead.

Hope this helps. Andy