electrical current in water
electrical current in water
I would like to know if anyone on this site has any information on how to protect an alloy boat from errant current in a marina setting? Going to a slip for the first time and I am concerned about corrosion due to electrical current in the water from leakage at the slips. Thank you, Mike
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kmorin
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Re: electrical current in water
clambo,
Will your slip provide your boat with a 'shore power' hookup that will be wired/plugged/connected to your boat?
Otherwise, I"m not (exactly) sure what you're asking about?
Cheers,
Kevin Morin
Kenai, AK
Will your slip provide your boat with a 'shore power' hookup that will be wired/plugged/connected to your boat?
Otherwise, I"m not (exactly) sure what you're asking about?
Cheers,
Kevin Morin
Kenai, AK
kmorin
Re: electrical current in water
The shore power question is important, are you using that feature? If so be aware that the green safety ground wire in your boat's power plug receptacle needs to first connect to an on-board isolator before making its way to your AC panel so to prevent stray DC current that may be present in the marina grounding circuit from making its way to your conductive aluminum hull and causing damage to any and all of your underwater metals. If you are not using the shore power system it is also possible to be affected by stray DC current emanating from an adjacent boat to yours if your boat happens to be in between that boat and a good ground like a steel piling. However, most rapidly occurring corrosion issues on aluminum boats are due to self-inflicted problems like your own poor wiring practices (can cause stray current corrosion) Incorrect or poor hull anode installation or painting your bottom with copper antifoul, etc. enables galvanic corrosion which is a much slower process but still harmful if not dealt with as soon as noticed.
1987 24' LaConner pilothouse workboat, 225 Suzuki
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Re: electrical current in water
Yes my boat will be connected to power on the docks. The power on the floating piers is on the top of the pilings, the 30 amp plugs run down the pilings to the plugs. Just trying to be pro-active. I don't really understand electrical issues so I am having a Marine electrical gut help me get it right. Same guy I had clean up wiring done by previous owner. Thank you for sharing your experience. Mike
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kmorin
- Donator 08, 09, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24
- Posts: 1744
- Joined: Mon Aug 18, 2008 1:37 am
- 15
- Location: Kenai, Alaska
Re: electrical current in water
clambo,
first thing is the hull wiring being done where all earths/grounds/bonds/DC Neg and AC (third leg) are common to one point on the hull & where all the loads /AC or DC have a two wire Plus and Minus lead?
The reason is to have the wiring carrying all current -not the hull to carry any current! All NEG and Green/AC bond (can be called ground but is super confusing when trying to discuss boat wiring) leading to one single point of 'bond' to the hull- with a single bolted point on an aluminum welded lug/padeye/location is best practice. This means any stray current has least resistance to single point of wiring to hull.
Should have welded on (if at all possible) 'zincs'/anodes/ sacrificial bare metal locations aft or on vertical of transom that are immersed when at rest waterline, and these should be located so they're accessible to spray/rinse/clean off/power wash if there's 'grass' in the harbor?
Then like Chaps explains you need to use an isolating xformer for the legs of the incoming power so that you boat's hull is not an 'anode' for the poorly designed shore power. Xformers are inductive not conductive so the stray current in the shore power is not conducted to your electrical system.
As to being in the flow of stray current from berth to berth, good bottom paint and clean anodes on the hull should to the job there? However, I have seen some bare aluminum seine skiff owners with inboard and outboard power where the hulls are tied into the space at the front end of a larger (50-60') hull where there's room at the turn of the waterline near the bow; hang pieces of aluminum over the skiff's sides to act as sacrificial anodes to the onboard generators' in the larger boats- running many hours a year even in harbor- 'leak' stray current into the waters of these slips. I don't know the results of those efforts? I do know they use large diameter copper cables (2/0 ) with 'arctic insulation', which is both very flexible and can be sealed at the ends with cable splice heat shrink sleeves which are put on the end lugs that are silver plated and soldered on to the copper cables with both silver solder and cable crimps.
But I don't know from any personal experience if this worked? - I did see one of these skiffs without bottom paint or sacrificial anodes that was pitted nearly through a 3/16" bottom in less than 2 months in between a crabber and seiner in the Homer, AK Harbor; so paying attention to where you're moored and what's around your skiff is important.
Cheers,
Kevin Morin
Kenai, AK
first thing is the hull wiring being done where all earths/grounds/bonds/DC Neg and AC (third leg) are common to one point on the hull & where all the loads /AC or DC have a two wire Plus and Minus lead?
The reason is to have the wiring carrying all current -not the hull to carry any current! All NEG and Green/AC bond (can be called ground but is super confusing when trying to discuss boat wiring) leading to one single point of 'bond' to the hull- with a single bolted point on an aluminum welded lug/padeye/location is best practice. This means any stray current has least resistance to single point of wiring to hull.
Should have welded on (if at all possible) 'zincs'/anodes/ sacrificial bare metal locations aft or on vertical of transom that are immersed when at rest waterline, and these should be located so they're accessible to spray/rinse/clean off/power wash if there's 'grass' in the harbor?
Then like Chaps explains you need to use an isolating xformer for the legs of the incoming power so that you boat's hull is not an 'anode' for the poorly designed shore power. Xformers are inductive not conductive so the stray current in the shore power is not conducted to your electrical system.
As to being in the flow of stray current from berth to berth, good bottom paint and clean anodes on the hull should to the job there? However, I have seen some bare aluminum seine skiff owners with inboard and outboard power where the hulls are tied into the space at the front end of a larger (50-60') hull where there's room at the turn of the waterline near the bow; hang pieces of aluminum over the skiff's sides to act as sacrificial anodes to the onboard generators' in the larger boats- running many hours a year even in harbor- 'leak' stray current into the waters of these slips. I don't know the results of those efforts? I do know they use large diameter copper cables (2/0 ) with 'arctic insulation', which is both very flexible and can be sealed at the ends with cable splice heat shrink sleeves which are put on the end lugs that are silver plated and soldered on to the copper cables with both silver solder and cable crimps.
But I don't know from any personal experience if this worked? - I did see one of these skiffs without bottom paint or sacrificial anodes that was pitted nearly through a 3/16" bottom in less than 2 months in between a crabber and seiner in the Homer, AK Harbor; so paying attention to where you're moored and what's around your skiff is important.
Cheers,
Kevin Morin
Kenai, AK
kmorin