My speedo has a range from 0-65 mph. It doesn't read anything untill I get to about 12mph. If I get a speedo that goes from 0-45 mph will it be more sensitive at lower speeds? My boat only goes about 31 mph so I don't need a 65 mph speedo. A lot of the lakes I boat on have 10 mph speed limit and I would like to know how fast I'm going.