Read the studies that have been done carefully...
We originally got two of the plastimos for Escape but our admittedly qualitative and informal testing showed little improvement over the bare boat using a standard raymarine dome 2KW radar. After talking to some of my Navy friends installed the small tri-lens and saw a huge improvement in detectability - the Navy really does use the large version. The davis echomaster as Chris said also works quite well and is a very economical, if more labor intensive, solution. The echomaster shows up significantly better than a bare rig - when we're on flotilla I usually act as the radar boat in fog, so I spend a lot of time studying returns. The AIS transponder is also a good idea if you're in an area with a lot of commercial traffic or large boats. Escape has a class B transponder and it's great for seeing larger boats that are equipped - tankers, freighters, ferries, yachts over 65 ft, etc - and they can see you. In addition to course, speed, CPOA it shows you their name and number - and ships that ignore you as a mystery boat answer a hail when you hail them by name. BUT, if they don't have AIS you don't see them and that can be very dangerous if you depend on it - I've never seen a lobsterboat with a transponder. If you install an AIS receiver or transponder you can also equip your crew with emergency beacons that will put a crew overboard warning with GPS location and steering directions on most current chartplotters - under $300 each. Our testing indicates that they work really well - immediately put the chartplotters (SIMRAD and Raymarine) into MOB mode with a heading and distance to the beacon, plotted position was accurate to about 10 feet. I have a friend who installed a CU-See Me on his boat and it works well - when hit by a radar it sends back a burst of interference that really shows up.
