I heard that if you use a stereo capacitor in a boat, they won't last very long because the boat is grounded only to the battery. Is this true?

I don't believe that would be supported by current electrical theory since the definition of ground means that you ultimately have to come back to the battery to complete the circuit.

Not sure, but that does not sound right. <BR> <BR>Why do you want to add a capacitor?

Well the battery is grounded to the block. Which is of equal ground strength as anything in your car.

A capacitor is pretty worthless in a boat IMO.

It really depends on the wiring and the batteries. If your sub amp is trying to pull more than these systems are capable of delivering instantaneously then a cap will help. If not, then it is a waste of money. Many car wiring systems suffer from such deficiencies that's why they are popular in cars.

mine went out before I ever got to use the damn thing. Condensation formed one morning on it, and that was that.

Kyle, <BR> <BR>Since a capacitor only provides instantaneous reserves to meet peak transients, I've always considered it to be of some esoteric value only in systems where the voltage is good. In a boat where you're often running below an optimum voltage, especially when at rest, I don't see a real benefit. <BR> <BR>David <BR>Earmark Marine