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Discussion Starter · #1 ·
My boat does not have a thru-hull for the black water output. I plan to drill a hole, and install the thru-hull and seacock. How far down relative to he waterline should the hole be drilled? Thanks in advance for the help.
 

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Discussion Starter · #6 ·
Ours is 6" above the water under the overhang aft, aft and above the rudder. It is placed so that nothing can run down the hull, (facing the water) but there is no resistance from the water, either.
The head on my boat is just behind the v-berth. It would be a long run to dump black water at the rear of the boat. Are long runs of tubing like this OK to do?
 

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Discussion Starter · #13 ·
The boat is a 1984 Bene First 35. Currently has a bag, but we will be converting to a rigid tank within the next year. The head is on the port side just behind the v-berth. The tanks is in the v-berth. The pump out is on the starboard side and about even with the back of the v-berth.
 

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Discussion Starter · #22 ·
...why did they not design it with an overboard discharge to begin with that isn't a little day sailer
I'm on Lake Michigan where "no overboard discharge" is the law...I think. Anyway, I had to sign a paper at the harbor that says "there is no way" to dump black water (hose disconnected or no hoe). So, the previous owners either ordered the boat with the hole not drilled, or they had it plugged. Currently, I can't find where the hole was drilled (looking from the inside)...if it was previously drilled. Additionally, one of the hoses coming off the Y-Valve is plugged and just laying in the area under the Y-value. I am going to look around a bit to see if I can find where the hole might have been drilled. There is a hull liner on this boat, so I should be able to find a hole in the hull liner if it was previously drilled.
 

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Discussion Starter · #36 ·
On a boat like this the typical setup is to have a "Y-valve" which directs the outflow to either the deck pump out fitting, or to a diaphragm pump or macerator, and then to a below the waterline through hull which can be secured in NDZs. All of this equipment is typically installed under the V berth, keeping the hose runs as short as possible. This was the factory setup on the Pearson 34, Cal 33, and O'day 34/35.

An issue with this is that the line can loose vacuum through the deck fitting and "Y-valve", making it hard to pump out. One solution is to put the pump before the "Y-valve", but you run the risk of someone activating the pump without opening the through hull...:puke

Another solution is to plumb a second pump out fitting into the tank, and eliminate the "Y-valve" entirely, and the likelyhood of vacuum leaks.

One last tidbit to minimize smelly hoses; make sure that any and all hoses are run so that they drain back into the holding tank, or through the through hull.
Hey, thanks very much. This all makes good sense and couldn't have figured it out on my own. We are headed there tomorrow to get this done. The first thing we will do is do a thorough search for any signs of the thru-hull...before drilling a new one. Thanks again!!
 

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Discussion Starter · #39 ·
I want to thank everyone for the help and the good discussion on creative techniques. I wanted to close everything out by giving an update on the work. There are a few pictures attached below to show what was done.

All of the current thru-hulls (head intake, head and galley sink in/out) are on the port side of the boat. The engine water intake is center and after near engine. A locker on the starboard side has the tubing for the pump out hose and fresh water loading hose. You can see this in the picture below. I put the black water hole in this locker. I plan to put a Y-valve on the pump out hose and route to macerator pump and thru-hull all in that locker. The picture below should be easier to understand than my wording.

At the end of the day after worrying about drilling a hole in my boat, dealing with all the dust for cutting with the dremel tool, mixing epoxy, etc, it was time to relax with a beer. The wife comes in about that time and says it is Metamucil time....so the last picture is of Beer-amucil. Don't knock it 'til you've tried it...kinda like a beer float...only not...:)
 

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Discussion Starter · #43 ·
Why am I not seeing a backing plate? :confused:

It should look something like this:...
The backing plate is there. I used 1/2" G-10. I decided not to go with a round shape. I went with the shape of the base plate as seen in the picture below.

....sorry I posted without the image. See the baseplate image in the next post.
 

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Discussion Starter · #46 · (Edited)
I've seen it the triangular base on another installation on a cruising yacht.

I don't think the bronze base should be mounted directly to the hull. The G-10 bonds well with the adhesive. I don't believe the bronze would adhere well to this.
 
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