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britcoal 07-30-2007 01:37 PM

Battery life?
 
I just launched a 36 wooden boat (strip planked) that was out of the water for over two years. We knew it would leak a lot but it hasn't been as bad as I expected.

There are two bilges, one 1100gph and another one 360gph. I know the 1100 has a 6amp fuse. The pump has been running every ~4 minutes for maybe 5 seconds each time (max of about 30 minutes a day)..

I have gone out to the boat and run the engine for 60 minutes each day since I am worried about the two batteries. Am I crazy? How long would they last, theoretically? They aren't running anything other than the pumps themselves.

(note: I have an aux shore power pump on board as well, but the float on it is much higher and the water would be above the floorboards before it would come on. I'd rather not deal with grimy bilge water cleanup in the cabin if I could).

Also, does anyone have any experience with these, or anything similar that is specifically for boats? http://www.batterystuff.com/solar-chargers/BSP512.html

Thanks!

Gary M 07-30-2007 02:16 PM

If your pump is only running 5 seconds each cycle I would find a way to lengthen that. Once the pump starts you want it to run for at least a few minutes. Your pump motor draws much more power starting than it does running so your battery will not last as long. It is hard on the little motor too, as it will get hot.

Gary

btrayfors 07-30-2007 02:56 PM

Battery capacity depends not only on the size and type of battery and its rated capacity, but it's age and condition. Capacity can vary GREATLY over time.

Figure that a battery should not be drawn down by more than about 50% of its capacity, so a NEW 100AH battery should not be expected to put out more than about 50AH before it reaches 50% capacity...about 12.2 volts...after which it should be fully charged.

You can figure total AH draw by multiplying the amperage load by the total time, e.g., 6 amps for 45 mins = 6 amps x .75 hours = 4.5AH.

Bill

britcoal 07-31-2007 11:43 AM

Quote:

Originally Posted by Gary M (Post 173052)
If your pump is only running 5 seconds each cycle I would find a way to lengthen that. Once the pump starts you want it to run for at least a few minutes. Your pump motor draws much more power starting than it does running so your battery will not last as long. It is hard on the little motor too, as it will get hot.

I have noticed that there is not a very large flow of water to the bilge pumps.. which is to say, when the pump comes on, the small section of the bilge which houses the pump is almost emptied out of water, and other sections (above and below the ribs directly forward and reverse of the pump) do not quickly drain into the pumps area.. the result is 5 seconds of pump action, followed by a slow process of water trickling/seeping/running to the lowest point (the bilge pump).. Eventually, the pump comes on again, but the procedure is repeated for another 5 seconds.

Is this a huge issue? The only thing I can see as a possible solution is figuring a way to drill larger "drain holes" on the bottom of the ribs between the ribs and chine(?). There is already a tiny amount of space there, obviously, but perhaps a 1/4 inch drill bit would help increase flow.. or all this is beyond necessary, I don't know.

At the end of the day, this is a launch issue, and once she swells up there is next to no leaking of any kind. Suggestions anyone?

Whampoa 07-31-2007 12:17 PM

Good Morning Britcoal,

I hope your water inflow has now slowed or ceased. I'm curious about your hull construction. Can you be any more specific about her being strip planked? Is she glued up and nailed from a series of square strips of approx. the thickness of her hull or is she more traditionally planked with cotton caulking and seam compound between the planks. I have seen both types of construction referred to as "strip planked". The first example is what I would call strip planked and the second I would call carvel planked.

Did you get a good idea of where the water was coming in from as she was taking up?

britcoal 07-31-2007 02:05 PM

Quote:

Originally Posted by Whampoa (Post 173511)
I'm curious about your hull construction. Can you be any more specific about her being strip planked?..

..Did you get a good idea of where the water was coming in from as she was taking up?

Whampoa,

The inflow of water has definitely ceased now, since it has been 4 days now. It was out of the water for almost three years so I did expect a lot of leaking initially.. most of the water was coming in through the cracks between planks. Some were merely seeping but there was a few spots where you could see a couple millimeters of actual water (i.e. you could see "through" the boat). These all closed up relatively quickly in my eyes, though I am not an expert and I am learning as I go.

However, for a boat that is older than 40, I'm pretty impressed. It is a Dickerson Ketch made on the Chesapeake in the early 60's. If I recall the survey, it is 2"(?) mahogany planks that are glued, nailed, and screwed. That sounded like overkill to me, but perhaps I've been reading about smaller boats like kayaks that are often only glued, for example. As far as your comment, re: "nailed from a series of square strips of apprx. thickness" - this sounds exactly correct. I am 100% certain she is stripped and not carvel. There is some sort of caulking (or glue?) but it is certainly not cotton - it is dark gray/black.

Gary M 07-31-2007 02:20 PM

You are lucky if she dried up that quickly. There are a couple of very pretty little carvel planked folkboats near me that have house hold sump pumps mounted in them and are plugged in all summer long and still occasional run.

That is just from being out for the winter. However I notice the owners are never in a rush to get them back into the water. A couple of other friends with wooden boats leave then in as long as possible in the fall and then get them back in early in the spring. It seems to help.

Gary

Whampoa 07-31-2007 04:10 PM

Great news to hear she has taken up OK. I have friends who have a 40' Dickerson that is strip planked out of mahogany.

I would imagine the glue was resourcinol but that is only a guess. Do you know what kind of fasteners she is nailed with?

Thanks for the response. Best of luck.

John

britcoal 07-31-2007 04:52 PM

Quote:

Originally Posted by Whampoa (Post 173577)
I have friends who have a 40' Dickerson that is strip planked out of mahogany..

..Do you know what kind of fasteners she is nailed with?

She was actually stored dry indoors for ~10 years during the 80's. The boy who grew up on the boat became a doctor and, right before his dad was to cut the boat up (as you can imagine its state) the kid said he wanted to restore it for nostalgia. In 1992 it got a complete overhaul and all the normal issues with Dickersons were addressed as well (keel bolts were replaced with bronze, etc etc).

Or at least this is how the story goes. It was then owned by my neighbours for ~8 years but they bought a Pearson 35 and I got a wheel of a deal (well, until it starts to eat away at the wallet).

The fasteners are silicone screws I think and I'm not sure about the nails. It is all written down in a notebook I am keeping (so much information, gah!) but I can't recall exactly right now.

Out of curiosity, do your friends with the 40' Dickerson have any stand out comments about the boat (good and bad?). I'd be interested to hear some real-world discussion. Is it a center cockpit? They seemed to make an awful lot of those after the 60's and especially when they started to move to fiber.

Whampoa 07-31-2007 05:19 PM

Drop me an email.

John


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