It looks like the alternator in my '84 ODay 28 kicked the bucket. I have a Universal M-15 diesel (Kubota 5411 11hp) with a 50amp Motorola alternator with an internal regulator. The voltage at the battery remains at 12.5 after I start the motor.A few questions:There are two wires out of the alternator, the thick red one that goes to the battery and a thin blue one. What is the blue one for, and more importantly, will a good alternator work without it connected?The list price for a replacement is $460. I'm wondering if anyone has had success with a suitable alternative. I sail in fresh water, have virtually no electronics (even my FM radio is a D cell boom box)and the most juice I use while running are the running lights at night. I'm not concerned with sparks since it's a diesel. Has anyone replaced this with a cheaper auto alternator? If so, what make/model did you use?