Are thru hulls suposed to be grounded?

[thefishingfreak]

All of my thru hulls have what looks like an old, Thin 16 gauge, ground wire on them.
Looks like when they repowered to diesel they just cut the wires.
Are the bronze thru-hulls and the stuffing boxes, rudder posts, shaft struts, etc suposed to grounded? and if so to what?
There is no grounding plate on this boat everything just grounds to the blocks and in turn to the negative of the battery.

[Nebe]

Isn't that how you ground your electronics?
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[thefishingfreak]

Yes everything Is grounded to the blocks
There are ground cables from the tower legs to the blocks also
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[Nebe]

Then id say no, given you have plenty of zincs to fight electrolysis.
My experience here is from a sailboat background, but boats are boats.
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[Raider Ronnie]

The wires are/were part of the bonding system.
Preventing electrolysis is it's purpose.
Mike, it's won't be cheap but being an older boat and the engines are out now is a good time to replace thru hulls.
I'm sure Dave Marciano would agree !

[Mr. Sandman]

RR..is correct. Those wires are for bonding. You connect everything metal to a common bonding wire and then to a large bonding plate (zinc overboard)
Electrical bonding: Information from Answers.com

Many small boats are not bonded. If you have a lot of metal fittings esp if they are in salt water (inside the bilge and out) I would recommend bonding everything. If you trailer or have a dry bilge and fittings are dry inboard and don't have any 110 operating appliances plugged in, etc then you can get away without bonding.

It also is suppose to help for lighting strikes. Lots of people argue this but it is suppose to give the charge a place to go (ie the water) . The reality is while it might do this many boats hit hard by lighting loose some/all electronics bonded or not.

FYI...My boat is not fully bonded. If I was building a new boat I would bond everything and have a big heavy copper cable running from bow to stern in the bilge. I would also not wire everything like they did. But what is done is done and it works OK so the effort to fix it has a low priority at the moment on the mental to-do list.


BTW, nice paint job on the engine room. What paint did you use (epoxy, poly? one part or two) and talk me thu the prep process.

[thefishingfreak]

All the thru hulls are new with the repower. New sea strainers etc. whatever wasn't done before I just change to all bronze. Deck drains, everything.

Originally Posted by Raider Ronnie

The wires are/were part of the bonding system.
Preventing electrolysis is it's purpose.
Mike, it's won't be cheap but being an older boat and the engines are out now is a good time to replace thru hulls.
I'm sure Dave Marciano would agree !

Posted from my iPhone/Mobile device

[thefishingfreak]

There is no thru hull plate/zinc. All these wires seem to be just tying together all the underwater metal part ls to the block/battery and in turn the zincs on the trim tabs.

Bilge is 2 part eurethane
for prep I steam cleaned the crud as best I could.
Then pulled all the wires and stuff.
Went nuts with a d/a with 36 grit then filled 29 years worth of random screw holes with kitty hair type glass filler & d/a again with 36.
Sprayed all the metal mounts,shaft couplers with rust acid prep.
I filled up 2 squirt bottles, one with greased lightning and another with bleach. And purple power in the scrub bucket. Soaked everywhere and scrubbed and scrubbed and scrubed again with red scuff pads. Rinse and dry.
2 part eurethane rolled out and sprayed where the roller couldn't reach.

Originally Posted by Mr. Sandman

RR..is correct. Those wires are for bonding. You connect everything metal to a common bonding wire and then to a large bonding plate (zinc overboard)
Electrical bonding: Information from Answers.com

Many small boats are not bonded. If you have a lot of metal fittings esp if they are in salt water (inside the bilge and out) I would recommend bonding everything. If you trailer or have a dry bilge and fittings are dry inboard and don't have any 110 operating appliances plugged in, etc then you can get away without bonding.

It also is suppose to help for lighting strikes. Lots of people argue this but it is suppose to give the charge a place to go (ie the water) . The reality is while it might do this many boats hit hard by lighting loose some/all electronics bonded or not.

FYI...My boat is not fully bonded. If I was building a new boat I would bond everything and have a big heavy copper cable running from bow to stern in the bilge. I would also not wire everything like they did. But what is done is done and it works OK so the effort to fix it has a low priority at the moment on the mental to-do list.


BTW, nice paint job on the engine room. What paint did you use (epoxy, poly? one part or two) and talk me thu the prep process.

Posted from my iPhone/Mobile device

[Raider Ronnie]

Originally Posted by thefishingfreak

All the thru hulls are new with the repower. New sea strainers etc. whatever wasn't done before I just change to all bronze. Deck drains, everything.
Posted from my iPhone/Mobile device

Cool.
My wife & kids will sleep better when we are out

[nightfighter]

The bonding/grounding system is to protect from both inside and out. Ground to diffuse any discharge or static. To guide lightning strike as directly as possible. And to protect against current from other boats or sources in a marina. Often see aluminum hulled boats hanging zinc "fish" over the side in a marina as sacrificial material that the current will attack before the hull, prop, shaft, struts, fittings, etc. Also have to be aware that lightning will often take out a thru hull transducer. Keep wooden plug close to that thru hull.
When I worked on aluminum hulls, I was taught to have every crew member empty their pockets before coming aboard. Pennies were what I was looking for. Over the side.... A lost penny in an aluminum bilge is no good
Paint looks awesome, Mike. Mount a mirror under each block before you put the motors back in. Makes it real easy to spot a leak.....

[MakoMike]

What everyone else has said about bonding. Bonding everything together is necessary for the zincs to protect all of the underwater metal, without the bonding the zincs can only protect the metal they are mounted on.

[thefishingfreak]

Ok thanks.
I'll go around and reconnect all the cut wires And make sure everything Is tied together.
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[TheSpecialist]

Bonding keeps all of those things at the same potential, and helps protect them. Things with different potential will corrode at different rates

[Jackbass]

Originally Posted by TheSpecialist

Bonding keeps all of those things at the same potential, and helps protect them. Things with different potential will corrode at different rates

Not to mention if you have a hand rail or metal rod holder that is bonded and you say touch a switch that is bonded while holding the unbonded steel DC voltage hurts bad.

Also every bonding termination use Noalox on it is available at Home Depot. It will prevent corrosion at the connection and also prevent galvanic corrosion. Dissimilar metals
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[Raider Ronnie]

Originally Posted by thefishingfreak

All of my thru hulls have what looks like an old, Thin 16 gauge, ground wire on them.
Looks like when they repowered to diesel they just cut the wires.
Are the bronze thru-hulls and the stuffing boxes, rudder posts, shaft struts, etc suposed to grounded? and if so to what?
There is no grounding plate on this boat everything just grounds to the blocks and in turn to the negative of the battery.

From my research in getting ready to do a bonding system on my boat, 16 gauge wire is way too small and useless.
6 gauge is recommended or 8 at minimum.
Here is a link a guy on the downeast forum I've been watching & waiting for some 6 gauge to be listed.
Hookup Stranded

[sokinwet]

This place has good prices. GenuineDealz.com - Marine Electrical, Boat Wire & Cable, Custom Battery Cables

[Mr. Sandman]

Thanks for that bilge paint info. I am going to paint mine this spring and was going to use interlux bilge coat. But it is a 1 part enamel. I don't know how tough it will be and was thinking of going with a 2 part epoxy instead. Wish I had more comments on the bilgecoat (since I already bought it) but I may shelve it for another day and use the two part. I think it will be a lot harder.

I did a lot of de-greasing when I go the boat and I use GUNK degreaser, let soak then scrub/rinse/repeat couple times and then use a purple degreaser that works pretty well and cleans off all the gunk film left behind. After that it is nice and clean.


Really looks nice in there...a clean bilge says a lot about the man

[Jackbass]

#6 wire is not that expensive. I cant imagine you needing anymore than say fifty feet. particularly if you buy pool type clamps so you are not cutting into the wire and losing length. You want to do it that way also so you do not lose conductivity. Just get the anti corrosion compound. Generally it is used for aluminum conductors but will serve the same purpose on copper in a marine environment.

50' of #6 will run you roughly 55$

oxide inhibitor

pool lug

grounding wire splice block insulated and corrosion resistant. if you choose to go that route

the links are just to show the equipment available. not to promote any individual website or product. I am in no way affiliated with elecdirect. just trying to be helpful

[Raider Ronnie]

Tinned wire can get price.
Bare copper strand wire NIT tinned doesn't belong in a boat.



QUOTE=Jackbass;990016]#6 wire is not that expensive. I cant imagine you needing anymore than say fifty feet. particularly if you buy pool type clamps so you are not cutting into the wire and losing length. You want to do it that way also so you do not lose conductivity. Just get the anti corrosion compound. Generally it is used for aluminum conductors but will serve the same purpose on copper in a marine environment.

50' of #6 will run you roughly 55$

oxide inhibitor

pool lug

grounding wire splice block insulated and corrosion resistant. if you choose to go that route

the links are just to show the equipment available. not to promote any individual website or product. I am in no way affiliated with elecdirect. just trying to be helpful[/QUOTE]
Posted from my iPhone/Mobile device

[Jackbass]

Originally Posted by Raider Ronnie

Tinned wire can get price.
Bare copper strand wire NIT tinned doesn't belong in a boat.



QUOTE=Jackbass;990016]#6 wire is not that expensive. I cant imagine you needing anymore than say fifty feet. particularly if you buy pool type clamps so you are not cutting into the wire and losing length. You want to do it that way also so you do not lose conductivity. Just get the anti corrosion compound. Generally it is used for aluminum conductors but will serve the same purpose on copper in a marine environment.

50' of #6 will run you roughly 55$

oxide inhibitor

pool lug

grounding wire splice block insulated and corrosion resistant. if you choose to go that route

the links are just to show the equipment available. not to promote any individual website or product. I am in no way affiliated with elecdirect. just trying to be helpful

Posted from my iPhone/Mobile device[/QUOTE]

If you were to leave it insulated and just strip the connections you needed should not be that much of a problem. Understood however copper does not like water and hates salt water.

Solid Tinned copper should cost you right around a dollar a foot maybe even a little less.