Sea Water Galley Pump

[Bill Starck]

Am considering the installation of an electric sea water galley pump on my CD 30. Rather than cutting in a new thru-hull fitting, I am thinking of putting a Y-valve on the engine raw water intake and a check valve on each branch. Any thoughts or suggestions??
Bill Starck

[Larry DeMers]

Bill,

I would not use a Y-valve there, if the valve is selecting the destination of the water coming in the engine cooling water seacock. That is dangerous..if you forget to switch the valve over, you risk overheating the engine. It also prevents you from using sea water in the galley when running the engine..inconvenient for all the expense and trouble of installing the pump and piping.

Since the frequency and amount of seawater drawn at any one time is likely to be small, why not plumb directly to the cooling water intake for the engine, using a tee fitting? Ordinarily this is frowned upon, as the water flow could be misdirected from the engines cooling requirements. But the water flow needed by the MD7A/B is so darn small compared to what the seacock will handle, I would think that quite a lot of water would need to be drawn elsewhere before there was a misdirection of the flow from the engine. I would think that a one-way valve would be needed in the new line to the sink only, to keep the engine from drawing in air from the sink circuit.


Just a thought this Thursday Morning.

Cheers,

Larry DeMers
s/v DeLaMer
Cape Dory 30 ~~Lake Superior~~

Am considering the installation of an electric sea water galley pump on my CD 30. Rather than cutting in a new thru-hull fitting, I am thinking of putting a Y-valve on the engine raw water intake and a check valve on each branch. Any thoughts or suggestions??
Bill Starck

demers@sgi.com

[Jack Bego]

Bill,

I would not use a Y-valve there, if the valve is selecting the destination of the water coming in the engine cooling water seacock. That is dangerous..if you forget to switch the valve over, you risk overheating the engine. It also prevents you from using sea water in the galley when running the engine..inconvenient for all the expense and trouble of installing the pump and piping.

Since the frequency and amount of seawater drawn at any one time is likely to be small, why not plumb directly to the cooling water intake for the engine, using a tee fitting? Ordinarily this is frowned upon, as the water flow could be misdirected from the engines cooling requirements. But the water flow needed by the MD7A/B is so darn small compared to what the seacock will handle, I would think that quite a lot of water would need to be drawn elsewhere before there was a misdirection of the flow from the engine. I would think that a one-way valve would be needed in the new line to the sink only, to keep the engine from drawing in air from the sink circuit.


Just a thought this Thursday Morning.

Cheers,

Larry DeMers
s/v DeLaMer
Cape Dory 30 ~~Lake Superior~~
I second this recommendation. My CD 28 is set up this way and it works just fine.

Jack Bego
CD 28, Sailing the up and down waters of Lake Travis, Austin, TX.

Am considering the installation of an electric sea water galley pump on my CD 30. Rather than cutting in a new thru-hull fitting, I am thinking of putting a Y-valve on the engine raw water intake and a check valve on each branch. Any thoughts or suggestions??
Bill Starck

jebiker@mindspring.com

[Ken Coit]

Bill,

Second try....

I agree with Larry about the Y-valve. Too much of an opportunity to mess up. I don't need any help along those lines.

However, I'm not so sure about depending on a check valve to keep my engine cooled. If it fails, the first clue will be a loud sucking sound from the sink; the second clue will be an engine getting overheated; the third clue will be an engine seizing; the fouth, a loud sucking sound from your wallet. And it could get worse. How fast are you at recovering from impending disaster?

An alternative would be to use the sink drain as an intake as well, using the same sea valve and cheap plastic plumbing parts above it to route water wherever you want. No need for under-the-sole plumbing; no need to risk the engine, etc., etc., and so forth. Downside is that you could only fill or drain the sink at a given time, but you were already resigned to only being able to use the intake when the engine was not running, so this might not be much more inconvenient.

Experiment with this is almost free, save the pump you need anyway; it is also relatively easy since it is all above the sole and under the sink.

There might be a safety or sanitary issue here that you ought to check out with the ABYC or other plumbing authority. I am not one.

At any rate, keep on sailing!

Ken
CD/36 Parfait
Raleigh, NC

Bill,

I would not use a Y-valve there, if the valve is selecting the destination of the water coming in the engine cooling water seacock. That is dangerous..if you forget to switch the valve over, you risk overheating the engine. It also prevents you from using sea water in the galley when running the engine..inconvenient for all the expense and trouble of installing the pump and piping.

Since the frequency and amount of seawater drawn at any one time is likely to be small, why not plumb directly to the cooling water intake for the engine, using a tee fitting? Ordinarily this is frowned upon, as the water flow could be misdirected from the engines cooling requirements. But the water flow needed by the MD7A/B is so darn small compared to what the seacock will handle, I would think that quite a lot of water would need to be drawn elsewhere before there was a misdirection of the flow from the engine. I would think that a one-way valve would be needed in the new line to the sink only, to keep the engine from drawing in air from the sink circuit.


Just a thought this Thursday Morning.

Cheers,

Larry DeMers
s/v DeLaMer
Cape Dory 30 ~~Lake Superior~~

Am considering the installation of an electric sea water galley pump on my CD 30. Rather than cutting in a new thru-hull fitting, I am thinking of putting a Y-valve on the engine raw water intake and a check valve on each branch. Any thoughts or suggestions??
Bill Starck

parfait@nc.rr.com

[Ben Thomas]

Bill, I worked this one out by moving the depth sounder which was mounted under the sinks on my cd. 30 forward to bow, access to the sounder is in small locker at base of v-berth. False bottom keeps items from laying on the transducer. The theory here was that by the time I got a read on depth I was already pretty well over that area. moving the transducer forward gives me a read on what I am approaching, with the right calibration, I bought myself a little more time to respond. theres nothing quite so humbling, than bumping bottom.

You can't be shy here, obviously. It took a lot of hard thinking before drilling began through the hull then glassing around the aperture. Anyway this freed up the hole in hull under sinks for the seacock/ intake for raw water. Good luck Ben



bt@benthomaslandscapers.com

[Larry DeMers]

Hi Ken,

The problem with taking the water from the galley sink seacock is that that drain line holds all sorts of crud in it from the sink. The column of water does get changed slowly over time if sailing/motoring, but the water drawn from that drain will be polluted with junk from the sink, and should not be considered useable water. The little tidbits of last nights dinner for instance, will still be in there, floating around. If some oil (be it engine oil, diesel oil or salad oil) is dumped down the sink for whatever reason, that oil will just sit on top of the water..for weeks even if sailing a lot.

I would also worry about the pump getting clogged up with the debris.

This is not approved by the ABYC nor any plumbing code I am aware of, but then they don't really have any jurisdiction over boats anyway. Even the ABYC is a voluntary standard. But this is one standard I would certainly recommend paying close attention to.

Now using the seacock from the depth sounders old location under the galley sink would be a better idea me thinks. Moving the sounder trnasducer improves the depth sounders warning ability for reasons that the poster states..and also eliminates problems with air bubbles and foam interrupting readings while heeled, which bedeviled the former depth sounders location under the galley sink.

Cheers,

Larry DeMers
s/v DeLaMer
Cape Dory 30 Lake Superior

Bill,

Second try....

I agree with Larry about the Y-valve. Too much of an opportunity to mess up. I don't need any help along those lines.

However, I'm not so sure about depending on a check valve to keep my engine cooled. If it fails, the first clue will be a loud sucking sound from the sink; the second clue will be an engine getting overheated; the third clue will be an engine seizing; the fouth, a loud sucking sound from your wallet. And it could get worse. How fast are you at recovering from impending disaster?

An alternative would be to use the sink drain as an intake as well, using the same sea valve and cheap plastic plumbing parts above it to route water wherever you want. No need for under-the-sole plumbing; no need to risk the engine, etc., etc., and so forth. Downside is that you could only fill or drain the sink at a given time, but you were already resigned to only being able to use the intake when the engine was not running, so this might not be much more inconvenient.

Experiment with this is almost free, save the pump you need anyway; it is also relatively easy since it is all above the sole and under the sink.

There might be a safety or sanitary issue here that you ought to check out with the ABYC or other plumbing authority. I am not one.

At any rate, keep on sailing!

Ken
CD/36 Parfait
Raleigh, NC

Bill,

I would not use a Y-valve there, if the valve is selecting the destination of the water coming in the engine cooling water seacock. That is dangerous..if you forget to switch the valve over, you risk overheating the engine. It also prevents you from using sea water in the galley when running the engine..inconvenient for all the expense and trouble of installing the pump and piping.

Since the frequency and amount of seawater drawn at any one time is likely to be small, why not plumb directly to the cooling water intake for the engine, using a tee fitting? Ordinarily this is frowned upon, as the water flow could be misdirected from the engines cooling requirements. But the water flow needed by the MD7A/B is so darn small compared to what the seacock will handle, I would think that quite a lot of water would need to be drawn elsewhere before there was a misdirection of the flow from the engine. I would think that a one-way valve would be needed in the new line to the sink only, to keep the engine from drawing in air from the sink circuit.


Just a thought this Thursday Morning.

Cheers,

Larry DeMers
s/v DeLaMer
Cape Dory 30 ~~Lake Superior~~

Am considering the installation of an electric sea water galley pump on my CD 30. Rather than cutting in a new thru-hull fitting, I am thinking of putting a Y-valve on the engine raw water intake and a check valve on each branch. Any thoughts or suggestions??
Bill Starck

demers@sgi.com

[Ken Coit]

Hi Ken,

The problem with taking the water from the galley sink seacock is that that drain line holds all sorts of crud in it from the sink. The column of water does get changed slowly over time if sailing/motoring, but the water drawn from that drain will be polluted with junk from the sink, and should not be considered useable water. The little tidbits of last nights dinner for instance, will still be in there, floating around. If some oil (be it engine oil, diesel oil or salad oil) is dumped down the sink for whatever reason, that oil will just sit on top of the water..for weeks even if sailing a lot.

I would also worry about the pump getting clogged up with the debris.

This is not approved by the ABYC nor any plumbing code I am aware of, but then they don't really have any jurisdiction over boats anyway. Even the ABYC is a voluntary standard. But this is one standard I would certainly recommend paying close attention to.

Now using the seacock from the depth sounders old location under the galley sink would be a better idea me thinks. Moving the sounder trnasducer improves the depth sounders warning ability for reasons that the poster states..and also eliminates problems with air bubbles and foam interrupting readings while heeled, which bedeviled the former depth sounders location under the galley sink.

Cheers,

Larry DeMers
s/v DeLaMer
Cape Dory 30 Lake Superior

Bill,

Second try....

I agree with Larry about the Y-valve. Too much of an opportunity to mess up. I don't need any help along those lines.

However, I'm not so sure about depending on a check valve to keep my engine cooled. If it fails, the first clue will be a loud sucking sound from the sink; the second clue will be an engine getting overheated; the third clue will be an engine seizing; the fouth, a loud sucking sound from your wallet. And it could get worse. How fast are you at recovering from impending disaster?

An alternative would be to use the sink drain as an intake as well, using the same sea valve and cheap plastic plumbing parts above it to route water wherever you want. No need for under-the-sole plumbing; no need to risk the engine, etc., etc., and so forth. Downside is that you could only fill or drain the sink at a given time, but you were already resigned to only being able to use the intake when the engine was not running, so this might not be much more inconvenient.

Experiment with this is almost free, save the pump you need anyway; it is also relatively easy since it is all above the sole and under the sink.

There might be a safety or sanitary issue here that you ought to check out with the ABYC or other plumbing authority. I am not one.

At any rate, keep on sailing!

Ken
CD/36 Parfait
Raleigh, NC

Bill,

I would not use a Y-valve there, if the valve is selecting the destination of the water coming in the engine cooling water seacock. That is dangerous..if you forget to switch the valve over, you risk overheating the engine. It also prevents you from using sea water in the galley when running the engine..inconvenient for all the expense and trouble of installing the pump and piping.

Since the frequency and amount of seawater drawn at any one time is likely to be small, why not plumb directly to the cooling water intake for the engine, using a tee fitting? Ordinarily this is frowned upon, as the water flow could be misdirected from the engines cooling requirements. But the water flow needed by the MD7A/B is so darn small compared to what the seacock will handle, I would think that quite a lot of water would need to be drawn elsewhere before there was a misdirection of the flow from the engine. I would think that a one-way valve would be needed in the new line to the sink only, to keep the engine from drawing in air from the sink circuit.


Just a thought this Thursday Morning.

Cheers,

Larry DeMers
s/v DeLaMer
Cape Dory 30 ~~Lake Superior~~

parfait@nc.rr.com

[tim]

If you already have a hole from moving a transducer, I guess it's a good idea to fill it with an intake seacock. Maybe. But I'd be kind of leery about drilling a new hole down there for your intake. I'd also hesitate about fooling with the engine's cooling intake. Seems to me, though, that it wouldn't be hard to run a half inch tube back from the head intake through the bilge back to the galley. It'd be a much longer run than from under the sink, but it'd be one less hole in the hull, and the head is much easier to share water with than the diesel. If the head overheats, it's more likely due to those burritos you ate than competition for seawater. And pvc is cheaper than seacocks. Also, the head intake is forward of the head outflow, which is a plus.

Hi Ken,

The problem with taking the water from the galley sink seacock is that that drain line holds all sorts of crud in it from the sink. The column of water does get changed slowly over time if sailing/motoring, but the water drawn from that drain will be polluted with junk from the sink, and should not be considered useable water. The little tidbits of last nights dinner for instance, will still be in there, floating around. If some oil (be it engine oil, diesel oil or salad oil) is dumped down the sink for whatever reason, that oil will just sit on top of the water..for weeks even if sailing a lot.

I would also worry about the pump getting clogged up with the debris.

This is not approved by the ABYC nor any plumbing code I am aware of, but then they don't really have any jurisdiction over boats anyway. Even the ABYC is a voluntary standard. But this is one standard I would certainly recommend paying close attention to.

Now using the seacock from the depth sounders old location under the galley sink would be a better idea me thinks. Moving the sounder trnasducer improves the depth sounders warning ability for reasons that the poster states..and also eliminates problems with air bubbles and foam interrupting readings while heeled, which bedeviled the former depth sounders location under the galley sink.

Cheers,

Larry DeMers
s/v DeLaMer
Cape Dory 30 Lake Superior

Bill,

Second try....

I agree with Larry about the Y-valve. Too much of an opportunity to mess up. I don't need any help along those lines.

However, I'm not so sure about depending on a check valve to keep my engine cooled. If it fails, the first clue will be a loud sucking sound from the sink; the second clue will be an engine getting overheated; the third clue will be an engine seizing; the fouth, a loud sucking sound from your wallet. And it could get worse. How fast are you at recovering from impending disaster?

An alternative would be to use the sink drain as an intake as well, using the same sea valve and cheap plastic plumbing parts above it to route water wherever you want. No need for under-the-sole plumbing; no need to risk the engine, etc., etc., and so forth. Downside is that you could only fill or drain the sink at a given time, but you were already resigned to only being able to use the intake when the engine was not running, so this might not be much more inconvenient.

Experiment with this is almost free, save the pump you need anyway; it is also relatively easy since it is all above the sole and under the sink.

There might be a safety or sanitary issue here that you ought to check out with the ABYC or other plumbing authority. I am not one.

At any rate, keep on sailing!

Ken
CD/36 Parfait
Raleigh, NC

Bill,

I would not use a Y-valve there, if the valve is selecting the destination of the water coming in the engine cooling water seacock. That is dangerous..if you forget to switch the valve over, you risk overheating the engine. It also prevents you from using sea water in the galley when running the engine..inconvenient for all the expense and trouble of installing the pump and piping.

Since the frequency and amount of seawater drawn at any one time is likely to be small, why not plumb directly to the cooling water intake for the engine, using a tee fitting? Ordinarily this is frowned upon, as the water flow could be misdirected from the engines cooling requirements. But the water flow needed by the MD7A/B is so darn small compared to what the seacock will handle, I would think that quite a lot of water would need to be drawn elsewhere before there was a misdirection of the flow from the engine. I would think that a one-way valve would be needed in the new line to the sink only, to keep the engine from drawing in air from the sink circuit.


Just a thought this Thursday Morning.

Cheers,

Larry DeMers
s/v DeLaMer
Cape Dory 30 ~~Lake Superior~~

[Bill Starck]

Thanks for your thoughts guys. When I posted my original message, I ment to say Y FITTING not Y valve. I think I'm going to try tieing into the engine sea water intake line with a check valve in the sink line, and watch the engine temp guage. I tend to look at it often when under power anyway. The transducer for my depth sounder has already been moved to the bow by a previous owner as Ben suggested but the hole has been filled in.
Bill Starck

[John R.]

Am considering the installation of an electric sea water galley pump on my CD 30. Rather than cutting in a new thru-hull fitting, I am thinking of putting a Y-valve on the engine raw water intake and a check valve on each branch. Any thoughts or suggestions??
Bill Starck

My opinion is don't install one in the first place. Over the years I've found them to be more trouble then they are worth in a salt water enviroment. Whether it be based on a electric or manual pump supplied system it still becomes high maintenance and they always seems to fail when you want to use them. Lubrication deteriorates too quickly in pump components in a salt water system unless you use an impeller type pump like your engine pump which has it's own maintenance headaches. I recommend when you need the occassional sea water in the galley just dip a bucket over the side or fill a jug with a gallon or so of sea water and keep it stowed. Believe me you will be glad you opted for the bucket in the long run.

In addition, I would not tap a feed off the engine cooling circuit to feed a supply pump, check valve or no check valve.

[Larry DeMers]

The only problem here is that the head seacock now has to either be turned on each time you want sea water in the galley or you have to leave the head seacock on..which is a strong negative in our boat anyway. With the head seacock open all the time, the only thing holding the water back is the small valve on the head itself..something that rips and tears easily on my Groco HF head. I sure would not depend on it to replace the seacocks function.

What might work better is what is known as a 'Sea Chest'. This is a larger diameter pipe connected to the seacock, with multiple taps off of it..for all water uses in that area...including engine cooling. The trick is to make certain that the sea chest is large enough diameter to accomodate all of the water uses simultaneously, that are tapped into it. This is a legal way to gather all intake seacocks into a single thru hull. Now for parts, you are into an area where you will need to be familiar with plumbing sources and practices..and West Marine etc. will be of little help here.

Good Luck,

Larry DeMers
s/v DeLaMer
Cape Dory 30

If you already have a hole from moving a transducer, I guess it's a good idea to fill it with an intake seacock. Maybe. But I'd be kind of leery about drilling a new hole down there for your intake. I'd also hesitate about fooling with the engine's cooling intake. Seems to me, though, that it wouldn't be hard to run a half inch tube back from the head intake through the bilge back to the galley. It'd be a much longer run than from under the sink, but it'd be one less hole in the hull, and the head is much easier to share water with than the diesel. If the head overheats, it's more likely due to those burritos you ate than competition for seawater. And pvc is cheaper than seacocks. Also, the head intake is forward of the head outflow, which is a plus.

Hi Ken,

The problem with taking the water from the galley sink seacock is that that drain line holds all sorts of crud in it from the sink. The column of water does get changed slowly over time if sailing/motoring, but the water drawn from that drain will be polluted with junk from the sink, and should not be considered useable water. The little tidbits of last nights dinner for instance, will still be in there, floating around. If some oil (be it engine oil, diesel oil or salad oil) is dumped down the sink for whatever reason, that oil will just sit on top of the water..for weeks even if sailing a lot.

I would also worry about the pump getting clogged up with the debris.

This is not approved by the ABYC nor any plumbing code I am aware of, but then they don't really have any jurisdiction over boats anyway. Even the ABYC is a voluntary standard. But this is one standard I would certainly recommend paying close attention to.

Now using the seacock from the depth sounders old location under the galley sink would be a better idea me thinks. Moving the sounder trnasducer improves the depth sounders warning ability for reasons that the poster states..and also eliminates problems with air bubbles and foam interrupting readings while heeled, which bedeviled the former depth sounders location under the galley sink.

Cheers,

Larry DeMers
s/v DeLaMer
Cape Dory 30 Lake Superior

Bill,

Second try....

I agree with Larry about the Y-valve. Too much of an opportunity to mess up. I don't need any help along those lines.

However, I'm not so sure about depending on a check valve to keep my engine cooled. If it fails, the first clue will be a loud sucking sound from the sink; the second clue will be an engine getting overheated; the third clue will be an engine seizing; the fouth, a loud sucking sound from your wallet. And it could get worse. How fast are you at recovering from impending disaster?

An alternative would be to use the sink drain as an intake as well, using the same sea valve and cheap plastic plumbing parts above it to route water wherever you want. No need for under-the-sole plumbing; no need to risk the engine, etc., etc., and so forth. Downside is that you could only fill or drain the sink at a given time, but you were already resigned to only being able to use the intake when the engine was not running, so this might not be much more inconvenient.

Experiment with this is almost free, save the pump you need anyway; it is also relatively easy since it is all above the sole and under the sink.

There might be a safety or sanitary issue here that you ought to check out with the ABYC or other plumbing authority. I am not one.

At any rate, keep on sailing!

Ken
CD/36 Parfait
Raleigh, NC

demers@sgi.com

[tim]

I definitely agree - the head seacock needs to remain closed when not in use. But so does every other seacock on board (except for the cockpit drains). So the negative about having to open the seacock every time, or just leave it open, applies equally to any seacock you might choose, be it the engine intake, the head, or a new seacock. The drawback w/ the head seacock is, of course, that it's just not that convenient to the sink, it's - what - ten whole feet away? For me, thats not much of a sacrifice, if it means I'm not monkeying around with the engine cooling.

The sea-chest idea might work, but it seems to me little more than a glorified tee-fitting - you'd still need some assurances that the engine won't back siphon water from the wrong place. As others have mentioned, a check-valve seems a little inadequate. Maybe a gate valve or a ball valve in addition to the check valve, so you can positively shut off the flow of water to the galley when the engine is turned on.

Also, on second thought, if I was to run a line back from the head, I wouldn't route it thru the bilge. I'd route it thru the bulkhead to the port settee tank, then up to the galley side by side with the freshwater hose.

Interesting discussion, this.

The only problem here is that the head seacock now has to either be turned on each time you want sea water in the galley or you have to leave the head seacock on..which is a strong negative in our boat anyway. With the head seacock open all the time, the only thing holding the water back is the small valve on the head itself..something that rips and tears easily on my Groco HF head. I sure would not depend on it to replace the seacocks function.

What might work better is what is known as a 'Sea Chest'. This is a larger diameter pipe connected to the seacock, with multiple taps off of it..for all water uses in that area...including engine cooling. The trick is to make certain that the sea chest is large enough diameter to accomodate all of the water uses simultaneously, that are tapped into it. This is a legal way to gather all intake seacocks into a single thru hull. Now for parts, you are into an area where you will need to be familiar with plumbing sources and practices..and West Marine etc. will be of little help here.

Good Luck,

Larry DeMers
s/v DeLaMer
Cape Dory 30

If you already have a hole from moving a transducer, I guess it's a good idea to fill it with an intake seacock. Maybe. But I'd be kind of leery about drilling a new hole down there for your intake. I'd also hesitate about fooling with the engine's cooling intake. Seems to me, though, that it wouldn't be hard to run a half inch tube back from the head intake through the bilge back to the galley. It'd be a much longer run than from under the sink, but it'd be one less hole in the hull, and the head is much easier to share water with than the diesel. If the head overheats, it's more likely due to those burritos you ate than competition for seawater. And pvc is cheaper than seacocks. Also, the head intake is forward of the head outflow, which is a plus.

Hi Ken,

The problem with taking the water from the galley sink seacock is that that drain line holds all sorts of crud in it from the sink. The column of water does get changed slowly over time if sailing/motoring, but the water drawn from that drain will be polluted with junk from the sink, and should not be considered useable water. The little tidbits of last nights dinner for instance, will still be in there, floating around. If some oil (be it engine oil, diesel oil or salad oil) is dumped down the sink for whatever reason, that oil will just sit on top of the water..for weeks even if sailing a lot.

I would also worry about the pump getting clogged up with the debris.

This is not approved by the ABYC nor any plumbing code I am aware of, but then they don't really have any jurisdiction over boats anyway. Even the ABYC is a voluntary standard. But this is one standard I would certainly recommend paying close attention to.

Now using the seacock from the depth sounders old location under the galley sink would be a better idea me thinks. Moving the sounder trnasducer improves the depth sounders warning ability for reasons that the poster states..and also eliminates problems with air bubbles and foam interrupting readings while heeled, which bedeviled the former depth sounders location under the galley sink.

Cheers,

Larry DeMers
s/v DeLaMer
Cape Dory 30 Lake Superior

[Will W.]

(
(_

Am considering the installation of an electric sea water galley pump on my CD 30. Rather than cutting in a new thru-hull fitting, I am thinking of putting a Y-valve on the engine raw water intake and a check valve on each branch. Any thoughts or suggestions??
Bill Starck

willwheatley@starpower.net

[Bill Starck]

The sea water would be used for pre-washing and rinsing dishes, general cleanup, etc. This would minimize the need to refill my fresh water tanks at other marinas with unknown water quality.
Bill Starck

[Larry DeMers]

After thinking on this a bit, it seems that there are three ways to get the seawater in to the galley sink via a pump of some kind.
a. Directly through a dedicated thruhull
b. Indirectly from the head seacock
c. Indirectly from the engine cooling water seacock, using a one way valve in series with this feed.

If 'A' is eliminated due to complexity or 'adding another hole into the hull', then all that is left are 'B' and 'C'.

In my mind, it would be plainy unacceptable to install a seawater tap in the head ('B') as it will entail the operators diversion to the head, not once but twice, everytime water is needed. Why not just plumb the head sink to the sea, and be done with it?

So then we are left with 'C' for a possible solution.
Objections voiced so far, have included that this is a dangerous practice because the engine could be affected by a misdirection of the water flow due to the seawater pump running when the engine was also running. Also, the engine could draw in air from the seawater pump circuit, if a one-way valve was not inserted in series to the seawater pump. I agree that this is a danger.

But I feel that you could put sufficient safeguards in place such that the engines cooling was assured, and that the operation of a seawater pump would be almost unafftected by the safeguards. See what you think;

I submit that the most often occasion of use for a seawater pump in the galley is associated around food prep and dishes afterwards. So appraoch the problem from that standpoint. It is unlikely that the seawater pump would be needed while the engine was running...but not impossible.

So:
Tap off of the engines cooling water intake thru hull, after the seacock. Plumb the water line, -made from the same heavy walled and wire reinforced hose as the cooling water intake hose is, to the electric water pump, placing a one-way valve in series with this line.

Connect a small 12vdc relay (with Double-Pole-Double-Throw contacts) across the engines oil pressure sensor (either side, really) and a good engine ground point.
This taps into a 12vdc source that is active only when the engine is running, causing the 12vdc relay to 'pick' or close, which then Opens a set of "Normally Closed" contacts on that relay.

The seawater pump is wired thru this set of Normally Closed contacts on the relay.

What will happen now is the seawater pump will run only when the engines ignition key is turned off. This prevents seawater pump operations when the engine is running, unless an overt action is taken to circumvent this safety by turning the ignition switch to off while the engine is running (shutting off the sensors for oil pressure and also the tachometer and alternator field voltages -but the engine continues to run as normal).

This would make the risks involved acceptable I think.

Hope this helps,

Larry DeMers
s/v DeLaMer
Cape Dory 30

The sea water would be used for pre-washing and rinsing dishes, general cleanup, etc. This would minimize the need to refill my fresh water tanks at other marinas with unknown water quality.
Bill Starck

demers@sgi.com