Side-Power’s SE50 and SE25 thrusters provide big performance in small tunnels. The SE25 has 55 pound-force in a 4.33-inch internal-diameter tunnel, and the SE50 has 110 pound-force in a 5.5-inch ID tunnel. The SE25 is for boats to 24 feet (depending on windage), the SE50 for vessels 27 to 37 feet. On/off and proportional controls are available. The 25 comes in 12V, the 50 in 12V or 24V, and in an ignition-protected version. The SE25 starts at $1,750; the SE50 is $2,500. Imtra, New Bedford, Massachusetts, (508) 995-7000. imtra.com

This article originally appeared in the April 2018 issue.