My 1985 25 foot Oday came with a nonwired Ems knotmeter.Does anyone know how to wire it?How do I use the calibrater box?The back has 6 terminals .2 for power,and 4 for expanding(?).This gauge reads from 0-10 knots .I bought two other used gauges .One reads 0-40 knots ,can this be used instead?The other one reads 0-12 knots but it uses a flat wire or ribbon wire.Will Moor Electronics be able to help?