A long wait
- Thread starter alumaman
- Start date
bigdogeh
Well-Known Member
My boat was built from the factory with the negative terminal (4 batteries) groundING (bonded?) to the hull with a cable the same size as the negative cable leading from negative terminal on battery to engine block (both engines). but also connected to a main negative bus bar where all electronics, etc connect. and it's my belief these guys knew how to build boats. what I take from the reading is that it is pretty much impossible to get away from having the hull being grounded as even water will conduct electricity and it is better to have everything at the same potential. it's when you have different potentials that corrosion will occur. there are still others that will argue that it's better to have a fully "floating system" where every effort is made to keep the DC system unbonded to the aluminum hull and all components connected to the hull.
there is alot of good reading on this and it seems just as many opinions. I think it's one of those things that people have to make their own mind up on what's right. It's my belief that having a completely 100% isolated system is almost impossible so in my case I believe it's better to have everything bonded to try to keep the electrical potentials the same.
here's a copy and paste that I thought might explain it a bit. and the thread it came from. read all pages if you want to see both sides of the argument.
http://www.boatdesign.net/forums/onboard-electronics-controls/wiring-aluminum-boat-17557.html
"Whoa guys we are getting way confused here over ground and groundING. There is a difference. I will asume for the moment we are talking just dc.
The ground wire in a DC system is the negative wire, generally black (yelllow in Europe). The red wire is the positive side. Look up the colors codes to find out what color your postive wires should be to different pieces of equipment. http://newboatbuilders.com/pages/elect5.html
DC systems are two wire systems and although the red is consider the hot side, actually both sides conduct current. It just goes around in a big circle through the red out to the light or whatever, and back to the battery through the black. ABYC standards and ISO and a bunch of other standards, all say the same thing. DON'T USE THE HULL OF A METAL BOAT AS A CONDUCTOR. So you will have a positive wire and a negative wire connected to all your DC electrical equipment.
The negative side is ground, and this is connected from the battery or from a ground bus (a board with a lot of terminals on it that have a common wire that goes to the negative post on the battery) to the engine block. The engine block is the common ground point.
So what is a groundING wire? That is the GREEN wire. Yes, DC systems can have a green wire. The green wire is used for two things. One is in case you have a ground fault (an accidental short to ground), the other is for what is commonly called bonding. Bonding is hooking all the metal fittings, metal cases of appliances, etc to the common ground, AND this can include the hull of the boat. ABYC and others allow this because NORMALLY this wire never carries any current.
Over on the AC side we have a three wire system as well. It also has a green wire (sometimes green with a yellow stripe). That same green wire is connected to the common ground, the engine block and thus to the green wire for the DC system.
However, as has been rather strongly pointed out the hull is never used as a conductor. This is due to the galvanic corrosion problem, and if you have a AC system with a green wire connected to the common ground, and get a short to ground, now the hull is suddenly conducting 120V ac! And you get AC leakage current into you DC system as well.
So Do Not use the hull as a ground. It can be connect to the groundING system for protection from galvanic corrosion and stray currents. But not as a conductor."
another interesting cut and paste....
"Let me explain once more why a ground strap or cable is good engineering practice.
In the first place fully isolated DC systems exist only in the imagination of some people.
Even with all electrical equipment fully isolated, there will always be a fairly low resistant path between DC and the engine block, caused by moisture, dirt and carbon deposits. Connecting the field windings of a starter motor or alternator to a terminal instead of the metal housing provides isolation only when the part is dry and unused. True isolation is always labelled with a class identification, referring to a minimum distance between conductors and housing, materials used and a test voltage of 2500 or 4000 volts.
In real life 99,99% of all marine engines have DC negative connected to the engine block. If you want to dispute, think of the millions of Mercruiser, OMC, Yanmar and Volvo engines and all outboards, regardless of brand names.
All of these have virtually 0 ohms resistance between DC minus and any part bolted to the engine.
In a stern drive setup, it is impossible to isolate the engine block from the hull, but a conventional prop shaft at first glance looks promising. Now assume that all precautions have been taken to keep the engine isolated from the hull, like isolated engine mounts, a non-conducting shaft coupling and fuel lines without a braided shield.
A simple test with a multimeter will reveal there is still a conductive path between the hull and the engine: seawater in the cooling hose.
Is that bad? No it isn't as long as all the DC wiring is in good order and nowhere is a wire touching the hull or a wet connector.
Under such circumstances it doesn't make a difference whether there is a ground strap or not, because there flows no current.
But if a short between DC positive and the hull or a current leak develops, the circuit closes and current will flow through the raw water pump and/or the walls within the heat exchanger. Dependent on the amount of current, it may take a few weeks or less than a day before corrosion has eaten through the 0.05 inch wall of a heat exchanger. And it may also make scars on the balls, rollers or needles in a bearing.
With a ground strap, none of that will occur. There will only be a blown fuse or damage to the part that created the short or leakage.
Reasoning should tell you what is wise and what isn't, not what is written in a handbook unless the author's reasoning is explained in detail."
__________________
there is alot of good reading on this and it seems just as many opinions. I think it's one of those things that people have to make their own mind up on what's right. It's my belief that having a completely 100% isolated system is almost impossible so in my case I believe it's better to have everything bonded to try to keep the electrical potentials the same.
here's a copy and paste that I thought might explain it a bit. and the thread it came from. read all pages if you want to see both sides of the argument.
http://www.boatdesign.net/forums/onboard-electronics-controls/wiring-aluminum-boat-17557.html
"Whoa guys we are getting way confused here over ground and groundING. There is a difference. I will asume for the moment we are talking just dc.
The ground wire in a DC system is the negative wire, generally black (yelllow in Europe). The red wire is the positive side. Look up the colors codes to find out what color your postive wires should be to different pieces of equipment. http://newboatbuilders.com/pages/elect5.html
DC systems are two wire systems and although the red is consider the hot side, actually both sides conduct current. It just goes around in a big circle through the red out to the light or whatever, and back to the battery through the black. ABYC standards and ISO and a bunch of other standards, all say the same thing. DON'T USE THE HULL OF A METAL BOAT AS A CONDUCTOR. So you will have a positive wire and a negative wire connected to all your DC electrical equipment.
The negative side is ground, and this is connected from the battery or from a ground bus (a board with a lot of terminals on it that have a common wire that goes to the negative post on the battery) to the engine block. The engine block is the common ground point.
So what is a groundING wire? That is the GREEN wire. Yes, DC systems can have a green wire. The green wire is used for two things. One is in case you have a ground fault (an accidental short to ground), the other is for what is commonly called bonding. Bonding is hooking all the metal fittings, metal cases of appliances, etc to the common ground, AND this can include the hull of the boat. ABYC and others allow this because NORMALLY this wire never carries any current.
Over on the AC side we have a three wire system as well. It also has a green wire (sometimes green with a yellow stripe). That same green wire is connected to the common ground, the engine block and thus to the green wire for the DC system.
However, as has been rather strongly pointed out the hull is never used as a conductor. This is due to the galvanic corrosion problem, and if you have a AC system with a green wire connected to the common ground, and get a short to ground, now the hull is suddenly conducting 120V ac! And you get AC leakage current into you DC system as well.
So Do Not use the hull as a ground. It can be connect to the groundING system for protection from galvanic corrosion and stray currents. But not as a conductor."
another interesting cut and paste....
"Let me explain once more why a ground strap or cable is good engineering practice.
In the first place fully isolated DC systems exist only in the imagination of some people.
Even with all electrical equipment fully isolated, there will always be a fairly low resistant path between DC and the engine block, caused by moisture, dirt and carbon deposits. Connecting the field windings of a starter motor or alternator to a terminal instead of the metal housing provides isolation only when the part is dry and unused. True isolation is always labelled with a class identification, referring to a minimum distance between conductors and housing, materials used and a test voltage of 2500 or 4000 volts.
In real life 99,99% of all marine engines have DC negative connected to the engine block. If you want to dispute, think of the millions of Mercruiser, OMC, Yanmar and Volvo engines and all outboards, regardless of brand names.
All of these have virtually 0 ohms resistance between DC minus and any part bolted to the engine.
In a stern drive setup, it is impossible to isolate the engine block from the hull, but a conventional prop shaft at first glance looks promising. Now assume that all precautions have been taken to keep the engine isolated from the hull, like isolated engine mounts, a non-conducting shaft coupling and fuel lines without a braided shield.
A simple test with a multimeter will reveal there is still a conductive path between the hull and the engine: seawater in the cooling hose.
Is that bad? No it isn't as long as all the DC wiring is in good order and nowhere is a wire touching the hull or a wet connector.
Under such circumstances it doesn't make a difference whether there is a ground strap or not, because there flows no current.
But if a short between DC positive and the hull or a current leak develops, the circuit closes and current will flow through the raw water pump and/or the walls within the heat exchanger. Dependent on the amount of current, it may take a few weeks or less than a day before corrosion has eaten through the 0.05 inch wall of a heat exchanger. And it may also make scars on the balls, rollers or needles in a bearing.
With a ground strap, none of that will occur. There will only be a blown fuse or damage to the part that created the short or leakage.
Reasoning should tell you what is wise and what isn't, not what is written in a handbook unless the author's reasoning is explained in detail."
__________________
Last edited:
you could get it welded. might not look good. backer tape and some JB weld? slightly different color but you have more control and it a DIY solution
alumaman
Well-Known Member
Thanks, I need some JB weld for another job so I'll give it a shot. The holes will eventually be covered by a down rigger so looks aren't to important. There's no way I would have mounted the equipment the way the previous owner did but he must have had a reason which made sense to him, when you buy used you have to take it warts and all. Still pretty damn happy with the new boat, water testing it tomorrow night.
Transport Canada
8.3.11 Every exposed conductive non-current part of electrical equipment that may normally be in contact with bilge or seawater shall be connected to a DC grounding system, except for small vessels not equipped with a DC grounding system, double insulated devices, and isolated metal parts in non-conductive material.
ABYC
DC grounded conductor - A current carrying conductor connected to the side of the power source.
2 Definitions - Continued that is intentionally maintained at boat ground potential. DC grounding conductor - A normally non-current carrying conductor used to connect metallic noncurrent carrying parts of direct current devices to the engine negative terminal, or its bus, for the purpose of minimizing stray current corrosion.
the rule applying the definition is section 11.18 and open to interpretation
would this not apply to all boats?
ChilliSpoons
Well-Known Member
Nice new ride.
I've fished numerous times in a boat with the same configuration. Tons of space under cover while still having a large dance floor for fighting fish.
I've fished numerous times in a boat with the same configuration. Tons of space under cover while still having a large dance floor for fighting fish.
alumaman
Well-Known Member
I'm going to get rid of the anchor next, it jams in my gut when loading the trailer. More holes to plug!
ChilliSpoons
Well-Known Member
Instead of plugging the holes with a product like JB Weld, why not just put in some stainless machine screws, washers and nuts?
I'm not a fan of JB Weld unless it's in an emergency situation or to scab somethings together around the house. On a sweet aluminum boat like yours it would just seem cheap.
I'm not a fan of JB Weld unless it's in an emergency situation or to scab somethings together around the house. On a sweet aluminum boat like yours it would just seem cheap.
Sculpin
Well-Known Member
Nice boat for sure. They sure are roomy compared to similar sized fiberlass boats.
My whole electrical system is a "closed loop" system with no ground wire to the hull. I have had no major electrolysis issues what so ever. A few pox (mill scale popping off in little flower configurations) near the swim grid due to a stainless steel reinforcing bar on my main engine mount. I am going to put some vinyl isolating material behind it and that should take care of that.
Good luck with the new boat. If you haven't already check out the Aluminum Alloy Boat forum, you should.
http://aluminumalloyboats.com/
There is a huge wealth of information on there.
Cheers,
Sculpin
My whole electrical system is a "closed loop" system with no ground wire to the hull. I have had no major electrolysis issues what so ever. A few pox (mill scale popping off in little flower configurations) near the swim grid due to a stainless steel reinforcing bar on my main engine mount. I am going to put some vinyl isolating material behind it and that should take care of that.
Good luck with the new boat. If you haven't already check out the Aluminum Alloy Boat forum, you should.
http://aluminumalloyboats.com/
There is a huge wealth of information on there.
Cheers,
Sculpin
alumaman
Well-Known Member
I found some black plugs/fasteners used for bodywork and they worked great. Put some caulking on them to hold and seal them so I'll see how they hold up.
triplenickel
Well-Known Member
Aluminum pop rivets work well too.
Fisherman Rob
Well-Known Member
Yea that anchor looks HUGE for the size of boat.
edit...Actually looking at the previous photos, it doesn't look all that big. Think it was just the wide angle in the last bow shot you posted that made it look bigger than it is. It is placed in an awkward spot though. Is there no anchor locker in the bow?
alumaman
Well-Known Member
There's an anchor locker in the bow, having said that the anchor "line" is 24' of 1/4" braided rope. There's not any room on the spool for a rode. It's pretty well useless for the fishing I'm going to do so it's going to go.
Fisherman Rob
Well-Known Member
Hmm 24' of rode at 1:5 scope means you can anchor in 5' of water max 
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