Got a new to me boat several months ago, and just like everybody else that has a boat, I want it to go faster. The boat is a 170 Triton pushed by a 90 Yamaha 2 stroke. Currently running a SS 18 pitch prop. Before doing anything else, I know I need to find out what kind of RPMs I'm running now. After doing some research I've found a lot of negative feedback on the tiny tachs. So I looked at several other brands of gauges. I'm sure having a permanent tach could be handy on other occasions besides dialing in the prop but honestly don't want to put more holes in the boat. So is there a good temporary tach option out there?