Capac reading

Corrosion, Paint, Through Hulls, etc.
Todml
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Capac reading

Postby Todml » Fri Aug 04, 2017 2:45 pm

Questions on Capac and hull protection. I have a new to me boat that did not come with shore power. I installed an isolation translation former rather than going with a galvanic isolator. My understanding is this will protect my boat from stray currents from other boats as I am isolated from dock ground.My capac reads around 6 or 7, could a 12 volt short to hull damage the hull and could this be one reason for low reading? Anodes are in pretty good shape but have not removed and cleaned hull and anode to ensure good bond. Also would condition of bottom paint affect reading? Thank you for any replies Todd
1988 Sportsman fly bridge
Twin 318 Chryslers
Straits of Mackinaw
Duncan Bay Boat Club

Todml
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Re: Capac reading

Postby Todml » Fri Aug 04, 2017 2:53 pm

Gotta love spell check/ isolation transformer
1988 Sportsman fly bridge
Twin 318 Chryslers
Straits of Mackinaw
Duncan Bay Boat Club

Fastjeff
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Re: Capac reading

Postby Fastjeff » Sat Aug 05, 2017 7:26 am

Yeah, but spell checkers can get you into trouble with certain words.

That CAPAC reading is far too low--should be 9 to 10. If you're in fresh water, I'd recommend adding magnesium to your trim tabs. A block added to one of mine bumped the readings up to 9 plus.

Jeff
"We live at the bottom of an ocean of air, not at the top." General Marvage Slatington

Todml
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Joined: Mon Jul 06, 2015 5:50 pm

Re: Capac reading

Postby Todml » Sat Aug 05, 2017 9:03 am

Jeff the trim tabs do have anodes but not sure of the bond and would assume they are aluminum? Do you think this reading can be caused from a 12 volt short to hull on my boat?
1988 Sportsman fly bridge
Twin 318 Chryslers
Straits of Mackinaw
Duncan Bay Boat Club

Todml
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Posts: 6
Joined: Mon Jul 06, 2015 5:50 pm

Re: Capac reading

Postby Todml » Sat Aug 05, 2017 10:13 am

I just ordered magnesium guppie to hang over side until boat is pulled and I can check anode bonds etc. and will redo bottom before next season.
1988 Sportsman fly bridge
Twin 318 Chryslers
Straits of Mackinaw
Duncan Bay Boat Club

jralbert
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Re: Capac reading

Postby jralbert » Sat Aug 05, 2017 10:39 am

A cleaning alone will improve the situation. I'd also clean the wire contacts on the meter itself. Did that once and got a slightly better reading.

I was in brackish (Chesapeake Bay) water and sometimes got low readings, too- 6 or 7. We had no galvanic problems discernible. But this is always fascinating stuff so yes, I'd be concerned. Pls report back after you use the guppy thing
-joel-
former owner 1988 '32 FB Sedan
Chesapeake Bay
twin 318 / 240 hp
Potomac MD