Feasability of using a truck alternator in a marine setting

[autumnbreeze27]

You can say you don't need an ignition protected alternator on a diesel boat, but if you have gas or propane on board for a dinghy or stove...

[boatpoker]

Originally Posted by autumnbreeze27

You can say you don't need an ignition protected alternator on a diesel boat, but if you have gas or propane on board for a dinghy or stove...

One would have to be pretty clueless to have propane lines running through an engine compartment or a propane system without an alarm under the stove or a galley bilge continguous to an engine bilge or propane not stored in a locker with direct overboard drainage.

[model 10]

Originally Posted by boatpoker

One would have to be pretty clueless to have propane lines running t and the tanks are venthrough an engine compartment or a propane system without an alarm under the stove or a galley bilge continguous to an engine bilge or propane not stored in a locker with direct overboard drainage.

That is a pretty high standard. Our propane line runs along the hull deck joint, then down to the stove and the tank locker is drained ovbd. But with propane sinking like it does, the stuff could end up in the bilge for any number of reasons. I added a detector at sole level but that is not the bilge or the engine in our case.
So boom, when you push the start button.

[boatpoker]

Originally Posted by Guy

That is a pretty high standard. Our propane line runs along the hull deck joint, then down to the stove and the tank locker is drained ovbd. But with propane sinking like it does, the stuff could end up in the bilge for any number of reasons. I added a detector at sole level but that is not the bilge or the engine in our case.
So boom, when you push the start button.

Don't think it's a high standard (ABYC, A-1) just a common sense one. After 23 yrs as a liveaboard I've learned to appreciate ABYC Standards as performance based common sense.

[RaymondR]

Originally Posted by captlloyd

My engine on my steel boat was isolated at the motor mounts. I also had a flexible coupling at the prop shaft. Theoretically then both the engine and alternator were isolated.

Aha, this is what I thought until I checked with a meter and found I still had a grounding connection between the hull and the motor. Pondering on it I realised that the engine controls were mounted directly onto the hull in the cockpit. Placing a rubber gasket between hull and the control mounting plate, heat shrinking the mounting studs and a nylon washer under the SS washer on each stud solved the problem.

The HF radio also provided a DC and signal ground to the hull but putting a capacitor bank in the grounding line insulated the DC ground whilst still providing a signal ground.

[roland stockham]

Originally Posted by Mike Two Moons

My concern is that the Delco alternator has a grounded housing, where as the Ample’s is insulated to negate stray current in the boat.

The previous alternator may have been grounded but the starter probably is not. also temp and pressure sensors commonly give ground connections. I believe the normal means of achieving a fully isolated electrical system is to use an isolating shaft coupling rather than worry about all the engine connections. Only difference between a 'real' marine alternator and a truck one is that the marine one has stainless connectors and the windings have a coating to minimize corrosion. In practice I have never found this to make a significant difference and the cost difference is extreme.