The performance of wireless Internet access is affected by many factors including obstructions between your radio and a Hotspot, excess ambient radio frequency noise in the Hotspot area and distance from your device to a Hotspot. Hotspots will usually be transmitting at near 1 watt of power but most built-in radios (laptop, desktop or PDA) transmit at only .03 watts. To improve your performance, you can add external antennas to mount high on your vessel, high power radios and even power amplifiers to dramatically improve signal. For a more detailed explanation click here.   

Good luck and good surfing!