2. Where's the Beef?
Towers endure a ton of torque. Look for beefy construction that will minimize motion. Aircraft-grade anodized aluminum (6061-T6 or 6063-T6) is typical, in 2 1/4- to 2 1/2-inch diameter. Other alternatives include stainless steel, in polished or brushed finishes. Colors are becoming increasingly popular, but with powder coating, insist on marine-grade polymers that will better resist corrosion, particularly in salt water.