Seacock installation

W

wknd@bernies

New Member
Feb 20, 2012
23
Lake Michigan
Boat Info
1989 280DA "Sundancer"
Engines
Mercruisers 4.3 LX
I have a 300 Sundancer and installing air and heat. I have one 3/4" seacock, but that runs my head. Looking to install another seacock to run my air but the locations left have a dart system thru hull, that no longer works..I now have a GPS system that takes care of that. Was going to pull that system out and use that location but the hole is 2". Any suggestions to what I can do? I was wanting to install another 3/4 inch seacock.

Thank you in advance

Bill
 
What is a "dart" system? Does it pose any risk to leave it there as-is and simply install the 3/4" thru-hull somewhere else? I'm thinking that it would be A LOT easier to simply glass-in a new backerplate than wrestle with removing the Dart thing, grinding/sanding both inside the bilge and underneath the hull (you're going to have to sand away a quite large radius), then finally getting to re-glassing. If not done properly, a 2" hole will let an awful lot of water in very quickly.

Wondering out loud here.... knowing that a head uses only a small amount of water (and only momentarily, at that), what about splitting the head's thru-hull to supply for both the head and the AC?
 
Loneranger said:
http://www.pbase.com/mainecruising/replacing_thruhulls

I would reglass the current 2 inch hole to place my new 3/4 seacock in. The article above gives all the detail you need much better than I could.
Click to expand...

Very good link, thanks for sharing. I liked the example of brass ball valve.

Lazy Daze said:
.....Wondering out loud here.... knowing that a head uses only a small amount of water (and only momentarily, at that), what about splitting the head's thru-hull to supply for both the head and the AC?
Click to expand...

Dennis, I'm not sure I'm following. Isn't the head thru-hull is for discharge? I know that some other boat builders use sea water for flushing the heads, but I didn't see this on SRs. So, if we're talking about the same discharge thru-hull, then it's a no-no at least just b/c of the CG requirement to have it closed with zip-tie on the handle.

I was thinking that it might be easier to install a reducer (say from 2" to 1") and run 1" to the A/C pump. It'll only make the A/C more efficient.
 
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Alex, you might be right - I guess it's the way I read what Bernie wrote:

wknd@bernies said:
I have one 3/4" seacock, but that runs my head.
Click to expand...

"runs"... I took that to mean his head uses raw water for flushing. Seeing as it's an '89, that opens it up for more possibilities.

IF it is for discharge... I don't even think we have to go as far as any CG requirements! Ick! :smt101

Edit: A reducer is a very good idea. My only concern there would be if it made the apparatus (thru-hull, seacock, reducer) to tall. It "could" create a problem where it could be snapped off if someone stepped on it. Obviously, sticking with all bronze would greatly lessen those chances.
 
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I am curious what a dart system is also? Is it for speed measurement since the GPS has replaced it? Reglassing a 2 inch hole would be a fair amount of work but it would be one less hole in the bottom of the boat. The key is doing it correctly.
 
Alex F said:
Very good link, thanks for sharing. I liked the example of brass ball valve.



Dennis, I'm not sure I'm following. Isn't the head thru-hull is for discharge? I know that some other boat builders use sea water for flushing the heads, but I didn't see this on SRs. So, if we're talking about the same discharge thru-hull, then it's a no-no at least just b/c of the CG requirement to have it closed with zip-tie on the handle.

I was thinking that it might be easier to install a reducer (say from 2" to 1") and run 1" to the A/C pump. It'll only make the A/C more efficient.
Click to expand...

My 1991 350 Sundancer uses a common 3/4" seacock for the intake of water for both the air conditioning and the head.
 
Someday Lady II said:
My 1991 350 Sundancer uses a common 3/4" seacock for the intake of water for both the air conditioning and the head.
Click to expand...


Hmm, it's good to know. My oldest SR with head was 2001, I guess they changed number of things, including the head flushing system. In this case Dennis was on the right track.

It sounds like Bill can simply copy your installation. The only question would be if your thru-hull has the scoop-strainer? The A/C needs "extra" seawater pickup when the unit is ON underway. I wonder how the scoop-strainer works (if you have one installed) on a common thru-hull for the head.

BTW, I'm in the same boat as you guys, I have no idea what "dart system" is.
 
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Alex F said:
It sounds like Bill can simply copy your installation. The only question would be if your thru-hull has the scoop-strainer? The A/C needs "extra" seawater pickup when the unit is ON underway. I wonder how the scoop-strainer works (if you have one installed) on a common thru-hull for the head.

BTW, I'm in the same boat as you guys, I have no idea what "dart system" is.
Click to expand...

My thru-hull has two wing nuts on top that when the lid is removed reveal a removable strainer that can be lifted out and cleaned. Is that what you call a scoop-strainer?
Same with me, no idea on the dart system.

Bob
 
Good. I'm glad I'm not the only one that doesn't know what a Dart system is!

The scoop sticks below the hull to... well... ummm.... "scoop" more water into the thru-hull. Good point, Alex.
 
Someday Lady II said:
My thru-hull has two wing nuts on top that when the lid is removed reveal a removable strainer that can be lifted out and cleaned. Is that what you call a scoop-strainer?
Same with me, no idea on the dart system.

Bob
Click to expand...

Bob, what you described is a sea-strainer. The scoop-strainer is at the bottom of the hull. Instead of the mushroom it looks like this:

scoop_strainer.jpg
 
I installed a/c on my boat and i split the seacock from the feed for my head. No problems at all but i only use my a/c at the dock not while underway. [no generator]
 
Alex is talking about the scoop under the hull as with the main engines. Not a strainer inside the ER that you clean out. A generator thru hull will not have a scoop under the hull so as to avoid pushing water into the generator while underway when the generator is not running.

Does the boat in question even have a generator?
 
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Thanks, Alex, for the pic. I couldn't think of a better way to explain it w/o using the word "scoop"!
 
I would question putting in a "scoop" style thru-hull for water feed to your heat-A/C. It seems to me it would then force water thru the pump and thruogh your system while under way. Could be wrong....

3684453.jpg
 
AKBASSKING said:
I would question putting in a "scoop" style thru-hull for water feed to your heat-A/C. It seems to me it would then force water thru the pump and thruogh your system while under way. Could be wrong....

3684453.jpg
Click to expand...

You're right and this is exactly why I brought it up. I'm just not sure what you were trying to show with the pic above (an A/C discharge, since it's SS?).

I assume that since this installation goes on 300DA it has a generator, thus it'll need to have the scoop-strainer for A/C raw water pickup. If using just the mushroom type thru-hull intake the A/C might be shutting down (while underway) due to lack of water flow.
 
AKBASSKING said:
This is the proper one:

6607618.jpg
Click to expand...

Yeap, this is the one to use if the OP doesn't have generator and the A/C won't be used while underway. But, in this case I would go with the idea of splitting the existing one for the head.
 
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