Extension cord... through water?

Trying to work through a first world problem. We (my dad) have a fishing boat. The fishing boat has a trolling motor, and the batteries should be charged after every use (read: they need to be charged after every use). We currently store the boat in the garage, launching it every time we use it. We would like to keep it moored in front of the house. 

Are there any safe ways to run an extension cord from the house to the water (approx 75 feet), and through the water to the boat (boat is approx 25 feet into the water, but with anchor it could get probably 50 feet away)? 

My thought was a 200 foot extension cord--plug that into a GFCI plug (Something like the below image), and then plug that into the on-board charger. All the plugs in the boat would then be put into a waterproof box. The plug at the house would be relatively protected by the awnings.

Would this be dangerous? Would I kill myself if I did this? Or worse, all the fish in the lake?

Also: I'd consider running a power line from the house to the shore, but that would be a lot more effort and I'd still have to figure out how to get the extension cord from the shore to the boat through the water.

And I may have just had an idea that "solves" this safer: Run it overhead. Would have to rig up some "power lines" that lift the cord the entire way, but it is probably possible.

How heavy duty is the trolling motor? How many batteries?

This sounds like a perfect job for a solar maintainer. 

A few years back we took my dad's bass boat to Raytown. Big berkeleying lake, took an hour to get to our spot flat out with the 9.9. Anyway, I accidentally left the charger on for a week before and the batteries were toast. No water, no power. On overcast days we were able to use the trolling motor at low speeds just off the solar maintainer we bought for the trip. 

A good 100 foot or longer outdoor rated power cord that could be used for other things will run $1.50+ per foot. Solar maintainer from harbor freight is under $40. 

A new and good quality extension cord is waterproof, so it should be perfectly fine. 

For a while...

That doesn't mean it is a good or safe installation.  Will it still be in good condition in 2 years?  How will you know if it is underwater and covered with algae?

RevRico said:

How heavy duty is the trolling motor? How many batteries?

This sounds like a perfect job for a solar maintainer. 

A few years back we took my dad's bass boat to Raytown. Big berkeleying lake, took an hour to get to our spot flat out with the 9.9. Anyway, I accidentally left the charger on for a week before and the batteries were toast. No water, no power. On overcast days we were able to use the trolling motor at low speeds just off the solar maintainer we bought for the trip. 

A good 100 foot or longer outdoor rated power cord that could be used for other things will run $1.50+ per foot. Solar maintainer from harbor freight is under $40. 

Well, it is 2 batteries at 24 volts right now. We will be upgrading shortly to 3/36. 

I really like the solar maintainer idea though. I'll have to look into that.

I like the solar maintainer idea.

SVreX said:

For a while...

 

That doesn't mean it is a good or safe installation.  Will it still be in good condition in 2 years?  How will you know if it is underwater and covered with algae?

Good point. I think it would have to be a regularly replaced item, which would get expensive. I also think it would not be left in the water except while charging, if I were to go through with this. 

I think I would go with the solar option.   People use them all the time for various remote locations.   Oil companies use them to maintain batteries  that are used to power telemetry communications at remote sites.

Electricity near water gets tricky if there is a "leak" that isn't properly grounded, people get electrocuted near dock because of it. 

I am an engineer but not an electrical engineer - I have heard stories and explanations from EE's that are pretty scary.

Please do not run any type of electrical cord through any body of water.  There were a couple of kids near here who were electrocuted a few years ago due to something like this.

Just about every marina in the world has cords draped through the water. I don't recommend it though. Not only is there the whole electrocution thing, galvanic corrosion is a serious concern when adding shore power to a boat. Most runabouts are not bonded to a sacrificial anode like larger boats because there is no power onboard. That can destroy any metal parts that are left in the water. Like the engine. Get a nick in the extension cord and the problem can be compounded and cause serious damage very quickly.

I also doubt a solar maintainer will charge the battery quick enough for use. They don't put out much wattage. You will probably need a larger panel and a charge controller to get the battery fully charged. Something in the 100 watt plus range. This would be the route I would take. A 100 watt panel with charge controller is about $150 on Amazon. That's enough to dump around 5 amps into the battery. If you use the boat every few days, you should be good to go. 

The marina where I camp in the summer has 100' orange 16ga extension cords running out the docks with triple-taps every 10 feet or so.  It gets rained on, waves splash on it, people walk on it.  No worries.  His isn't even on a GFCI.  If it falls in the water it just trips the breaker.

Safe? no.  Code?  no.  But it works just fine.

Pull the batteries and charge them on shore.


This is one of those where "I saw someone do it and he didn't die" isn't good enough.

Anchor the boat off-shore in front of the house and there is no dock? How do you get to and from the boat anchored 25-50 ft from shore? Wouldn't be much of an issue with a dock, just run wires to the dock and wire up the dock to handle this. There are waterproof boxes for outlets. I know, long term solution that isn't cheap. I'd at least bring the boat to shore (run aground) and like you mentioned, use an overhead extension cord. At least for the short term.

wlkelley3 said:

Anchor the boat off-shore in front of the house and there is no dock? How do you get to and from the boat anchored 25-50 ft from shore? 

We walk. Very slow drop off with a sandy bottom, boat is probably only in 2 feet of water where it is moored. The water is as high as I can remember it right now, but we'd still probably have to go out 300 yards before it is even up to our chests. 3 years ago, when it was probably close to record lows, it would have been about 500 yards to chest deep.