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Shorting battery due to flooding cockpit

 
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seabrook



Joined: 15 Apr 2006
Posts: 9
City/Region: Merville, Canada
State or Province: BC
C-Dory Year: 2005
C-Dory Model: 22 Cruiser
Vessel Name: C-Brook
PostPosted: Sun May 21, 2006 11:37 am    Post subject: Shorting battery due to flooding cockpit Reply with quote

Hello C-Brats, our 22' cruiser C-Brook has two batteries #1 is mounted in the starboard lazerette and #2 is in a plastic battery box mounted on the deck in the cockpit between the fuel tanks. I normally start the outboards using battery #1 then after a short period to recharge it I select the battery switch to both. Yesterday my wife and I got caught in some rather lumpy seas off Cape Mudge as we were heading back to Campbell River. It occured to me that if we took a large following sea that flooded the cockpit the #2 battery could get shorted out and since the battery switch was selected to both it could also short out battery #1. Is this correct? If so it would be good practise to select the higher mounted #1 battery when in big seas. Also if both batteries were shorted would the outboard continue to run?

Ron & Linda Seabrook
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Sea Wolf



Joined: 01 Nov 2003
Posts: 8650
City/Region: Redding
State or Province: CA
C-Dory Year: 1987
C-Dory Model: 22 Cruiser
Vessel Name: Sea Wolf
Photos: Sea Wolf
PostPosted: Sun May 21, 2006 12:22 pm    Post subject: Reply with quote

seabrook-

Your concern is quite legitimate. However, while salt water is conductive, I don't believe it will short out the lower battery across the submerged terminals so much as to cause the voltage to drop to a dangerous level unless it were left in that condition for some time with the engine (alternator) not running.

As a guess, I doublt more than 25 amps of current would flow across the top of one battery, and with the alternator running (16-40 amps output), you'd not be in immediate danger.

However, if the salt water immersion were to include more terminals and electrical equipment, the answer could be significantly different.

I'd be sure my battery box liid was well secured for starters. Also, coat the terminals and posts with dialectric grease to minimize exposure of current conducting metal. Alternately, the terminal metal parts not conducting current can be coated with Plastisol (plastic tool handle liquid that will harden). Finally, the battery box could be moved elsewhere or the box left where it is and bolted down on some very secure platform to raise it 8-10 inches, depending on space available overhead.

If a very large sea were to dump ("POOP") on you from astern, the situation would be more serious, but the battery in the starboard lazarette wouldn't be flooded unless you were close to having the gunnels level with the sea level, in which case it's time to abandon ship anyway.

If I were operating in such conditions regularly, I'd also be very concerned with the bilge pump capacity available. Have not one, but two pumps. Each should be wired separately and should have a minimum capacity of 2000 gph (IMHO). Your best defense is to be able to recover quickly by removing the water. Too large a POOP and you're done anyway, as sea water will enter the boat as fast or faster than it can be pumped out!

Do you have a "plate" that blocks the cut out at the fron end of the motor well to raise the entrance level 12 or so inches? This is another easy defence in the War Against the Poop Gods!

I need to point out that what I've said above about the battery situation is just a product of my rational approach to the problem. Examination of anectodal accounts of swampings may or may not be in agreement. If you refer to such accounts, keep in mind whether you're reading about inboards or outboards, what kind of hull and bilge configuration is represented, and where and how exactly where the batteries and wiring are placed. It would be very easy over-generalize from such information.

HTH!

Joe.

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Sea Wolf, C-Brat #31
Lake Shasta, California

"Most of my money I spent on boats and women. The rest I squandered'. " -Annonymous
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thataway



Joined: 02 Nov 2003
Posts: 20779
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
PostPosted: Sun May 21, 2006 12:53 pm    Post subject: Reply with quote

Both of the batteries in my 22 are out of harms way--the engine battery in the lazarette, the house battery under the galley. I agree with Sea Wolf's assesments. Even if the battery were covered with sea water, it would not short out. I have used small batteries in RIB's and skiffs which have gotten saturated with salt water (breaking surf landng) and they went right on and started the engines a few minutes later.

As for swamping a 22 Cruiser--It is possiable I am sure--but it would have to be some pretty difficult conditions and probably involve operator error. I had a 18 foot deep V with a cockpit arrangement very similar to the C Dory. I used to run back and forth to Catalinia in. One day one of my friends lost his dinghy which he was towing, and I went out to look for it--the seas were easily12 feet and breaking in a North Westerly storm. I only took water over the tansom when I slowed down and didn't pay attention to the wave pattern, while talking to the other boater. The bilge pumps removed the water, and although both batteries were immersed the engine continued to run.

"Take precautions--but don't worry about it.

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Bob Austin
Thataway
Thataway (Ex Seaweed) 2007 25 C Dory May 2018 to Oct. 2021
Thisaway 2006 22' CDory November 2011 to May 2018
Caracal 18 140 Suzuki 2007 to present
Thataway TomCat 255 150 Suzukis June 2006 thru August 2011
C Pelican; 1992, 22 Cruiser, 2002 thru 2006
Frequent Sea; 2003 C D 25, 2007 thru 2009
KA6PKB
Home port: Pensacola FL
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seabrook



Joined: 15 Apr 2006
Posts: 9
City/Region: Merville, Canada
State or Province: BC
C-Dory Year: 2005
C-Dory Model: 22 Cruiser
Vessel Name: C-Brook
PostPosted: Mon May 22, 2006 12:14 pm    Post subject: Reply with quote

Interesting, its reassuring that the battery will not short when submerged.
I will consider adding a second bilge pump and a transom wave blocker, thanks for the advice.
Ron Seabrook
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Falco



Joined: 20 Dec 2004
Posts: 164
City/Region: Flagstaff
State or Province: AZ
C-Dory Year: 2004
C-Dory Model: 22 Cruiser
Photos: Bucking Coho
PostPosted: Mon May 22, 2006 12:58 pm    Post subject: Reply with quote

Question to Seabrooks:

Why not eliminate all (most) doubt and place the #2 battery adjacent the #1 battery in the starboard lazarette? Alternative: place #2 in port lazarette.
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