Understanding the CAPAC

carl
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Understanding the CAPAC

Postby carl » Mon Feb 06, 2017 10:36 am

BigM
Last edited by carl on Wed Jul 10, 2019 11:07 am, edited 1 time in total.

jralbert
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Re: Understanding the CAPAC

Postby jralbert » Mon Feb 06, 2017 11:04 am

Carl..I'll attempt this but I can't conjure up all the tech detail. Yes, it''s a thru hull, usually mounted (at least it was in the '88 FBS model I had and others where the helm was port side) aft of mid=-ships on the port side. It measure the electrical potential of the hull using a silver/silver chloride metal detection plate on the water side. I believe it's grounded to the hull inside and is not connected to the ship's electrical system. You can't switch it on/off. Pressing the button on the readout panel closes a circuit and causes the needle to register the potential. For our hulls, the proper range is marked on the instrument.

Silver/silver chloride plate is quite thin and delicate so never scrub it down with anything tougher than a sponge (lightly please) and don't paint it because paint interferes with its contact with the water, rendering it useless.

I will try to find my manual and post it. Stay tuned. The other good news is that the company survived but I don't remember the successor name - it was posted here a long time ago. They primarily make units for big ships, including spendy aluminum yachts, but parts for the original Capac may be available in some form. It's an important tool to keep the hull safe from deterioration.

UPDATE: I COULD NOT UPLOAD THE CAPAC PDF FILE. SITE SAYS IT DOESN"T RECOGNIZE THE PDF FORMAT> ADMIN????
-joel-
former owner 1988 '32 FB Sedan
Chesapeake Bay
twin 318 / 240 hp
Potomac MD

EWRice
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Re: Understanding the CAPAC

Postby EWRice » Mon Feb 06, 2017 11:34 am

My understanding of the CAPAC system is as follows:
All you are doing is measuring the voltage your boat creates by being in the water. The gauge reads milivolts and the button just completes the circuit to the gauge. The circuit is separate from your AC or DC system. It reads DC volts.

One lead from the meter is connected to the hull, usually a stringer near the engines. The other lead is connected to a special insulated thru hull on the port side, about midship, just up from the keel. Kind of looks like a 8" or so dinner plate with a 2" metal disc in the middle. The plastic insulator "the plate" can be painted. The metal disc cannot. Don't scrape it, blast it or any other abrasive as it has a silver coating.

The short of it is the lake is the battery electrolyte and your boat is one of the plates inside the battery. A certain amount of current is good. Go beyond that and you have problems.
Muskegon Lake
1972 32' Express flybridge
"AL13"
Twin 318s
On board air & prime 920
1963 Thompson Super Sea Lancer
Graymarine 327
1961 Alumacraft 12'
'55 10hp Johnson

carl
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Re: Understanding the CAPAC

Postby carl » Mon Feb 06, 2017 11:47 am

BigM
Last edited by carl on Wed Jul 10, 2019 11:07 am, edited 3 times in total.

carl
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Re: Understanding the CAPAC

Postby carl » Mon Feb 06, 2017 12:32 pm

BigM
Last edited by carl on Wed Jul 10, 2019 11:06 am, edited 2 times in total.

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Busia
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Re: Understanding the CAPAC

Postby Busia » Mon Feb 06, 2017 2:14 pm

Wow! $500 for the meter! Yes, this is just a little electrical cell " battery" you are making with the hull and sensor, with the water as the electrolyte. Go to boatzincs.com to read and learn all about this. Best prices and service when you want to buy anodes. They have a test electrode for $125 and get a $10 VOM and you have the same thing. I put a new bottom on my boat and got rid of all the holes I could. I removed the sensor and now just hang it over the side with my VOM set to mV in series with the sensor and the hull. --Ed
BUSIA
located in Ketchikan, Alaska. Gods country
32 foot Marinette express. (no fly bridge)
twin 350 Crusader (Chev 350) engines
1:1 Borg Warner velvet drive transmissions
Closed cooling (antifreeze in the engine)
Proud to be retired IBEW

carl
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Re: Understanding the CAPAC

Postby carl » Mon Feb 06, 2017 2:43 pm

BigM
Last edited by carl on Wed Jul 10, 2019 11:06 am, edited 1 time in total.

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Busia
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Re: Understanding the CAPAC

Postby Busia » Mon Feb 06, 2017 3:27 pm

Welded 3/16" new bottom on the whole hull. Holes can be patched too if you find a good welder.
BUSIA
located in Ketchikan, Alaska. Gods country
32 foot Marinette express. (no fly bridge)
twin 350 Crusader (Chev 350) engines
1:1 Borg Warner velvet drive transmissions
Closed cooling (antifreeze in the engine)
Proud to be retired IBEW

jralbert
Site Admin
Posts: 677
Joined: Fri Jul 11, 2014 9:15 pm

Re: Understanding the CAPAC

Postby jralbert » Mon Feb 06, 2017 11:50 pm

check the attachments - lots of pages but here is the Capac Manual. The site wouldn't let me upload PDF's so here is a jpg version. Sorry if the print is light.
Attachments
Capac Monitor Manual (2).jpg
Capac Monitor Manual (3).jpg
Capac Monitor Manual (4).jpg
Capac Monitor Manual (5).jpg
Capac Monitor Manual (6).jpg
Capac Monitor Manual (7).jpg
Capac Monitor Manual (8).jpg
Capac Monitor Manual (9).jpg
Capac Monitor Manual (10).jpg
Capac Monitor Manual (11).jpg
Capac Monitor Manual (12).jpg
Capac Monitor Manual (13).jpg
Capac Monitor Manual (14).jpg
Capac Monitor Manual (15).jpg
Capac Monitor Manual (16).jpg
Capac Monitor Manual (17).jpg
Capac Monitor Manual (18).jpg
Capac Monitor Manual (19).jpg
-joel-
former owner 1988 '32 FB Sedan
Chesapeake Bay
twin 318 / 240 hp
Potomac MD

carl
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Posts: 355
Joined: Sun Feb 08, 2015 5:58 pm

Re: Understanding the CAPAC

Postby carl » Tue Feb 07, 2017 6:04 am

BigM
Last edited by carl on Wed Jul 10, 2019 11:05 am, edited 2 times in total.