Raising sail alone
Since the original poster doesn''t say whether he has auxilliay power (on such a small boat, one cannot assume), he may still be left with his question…
<b>If you do have an outboard:</b>
A tiller tamer only lashes the tiller in place; the boat will certainly fall off the wind before the main can be raised the majority of the time. In a 17-ft. boat, just leaving the tiller for the cabintop will do it. Still, if you''e quick, and in light wind, this may be perfectly acceptable. For more control, you could devise a steering line, i.e., a loop rigged to the tiller, outboard around your stern cleats, forward, and then across the cabintop, where a foot-loop is tied in. You can then effectively keep the bow into the wind while raising the main.
For any sailraising maneuver, a freed mainsheet and snugged topping lift are important for quick feeding of the boltrope (on a boat so small, I''m assuming a boltrope instead of plastic sail slides) into the mast groove and to avoid drag which will hamper your effort on the halyard. Always stand on the weather (upwind) side of the boom.
<b>If you do not have auxiliary propulsion:</b>
I''d suggest raising all sail dockside before casting off.
Such small boats are usually launched from a ramp. If you have no motor (or even if you do) and you are able to launch next to a dock, and can row or motor to the dock, orient the boat so that the boom can point downwind without fouling anything, and assuming you can sail off the dock safely, do so. Any of the classic "learning to sail" handbooks will give descriptions & diagrams about how to accomplish this under various wind/current situations and dock configurations.
A less seamanlike maneuver would be to raise the main while drifting down with no propulsion. In this scenario, a tiller tamer won''t help you much. Until the main is up and sheeted in, you''ll drift downwind crab-wise, causing a hazard to those around you. If you must, and have the searoom, just make sure it''s clear downwind, that you''ve made all the required preparations in advance (topping lift, running rigging, free mainsheet, loose sailties, etc.) and jump to the job. On a big lake or the open ocean, this may be feasable, but is still considered bad form. Once you''re under main alone, you can use the ''tamer to let you more easily raise whatever small jib she carries. With only a main sheeted hard in and the tiller lashed amidship, your small boat is likely to sail an upwind coarse with noticeable leeway, or possibly "short tack" with the bow crossing back and forth across the wind (you may even cause a roll tack by your shifting bodyweight).
InRe to a downhaul, I heartily agree with Jonathan: it can make singlehanding much more pleasureable. I might add that, singlehanding with a boltrope main, you simply cannot do without a lazy jack system to catch that main when it all runs out of the groove ans spills out on your cabintop and cockpit. I created a very serviceable one from a few screws, tangs, a couple hundred feet of very light line, a tube of Lock-tite (to keep the screws from backing out and insulate the SS screws from the aluminum mast), a screwdriver & an electric drill, for a boat almost 50% larger than yours. Of course off-the-shelf systems are available in every boat store. You will smile every time you use it.
Hope this is long wind blew you something useful,