Raw Water Strainer Opinion

Skinny Dippin's old strainer isn't in the best condition and I would also want to relocate it. I saw this on ShipShapeTV this week and like the idea of it.

Perko Flushing Bronze Sea Strainer

Any opinions on having a hose connection on a strainer? Can a hose supply enough water to keep a diesel cool while it flushes?

Tom-

GonzoF1 said:

Skinny Dippin's old strainer isn't in the best condition and I would also want to relocate it. I saw this on ShipShapeTV this week and like the idea of it.

Perko Flushing Bronze Sea Strainer

Any opinions on having a hose connection on a strainer? Can a hose supply enough water to keep a diesel cool while it flushes?

Tom-

Click to expand...

No opinion on the particular strainer or Perko, but did you notice all the "wrong" (I could use the word "lies") information they both stated in trying to sell that product?

"Most blue water boats use seawater to cool their engines." - I don't think so, not at all. I/O runabouts and small cruisers, perhaps, but I'm pretty sure most "blue water boats" will be found to have closed coolong systems.

There's no harm in flushing the seawater side of a closed cooling system, but these systems are designed not to need flushing on a day to day basis.

Would a hose supply enough water to keep a disesl cool while it flushes? It depends on the diameter and length of the hose and the water pressure at the faucet, but I suspect it would. You would be running at idle speed and only for a few minutes. You can run a diesel at idle speed for several minutes with no cooling water flow. Don't ask me how I know that.

I have a 1 inch raw water pump and it takes two 3/4 inch hoses running full to run my little Kubota at 1200 rpm. Faster than that the hoses won't keep up.
Might be nice for winterization or a quick flush though.

Well, I haven't flushed the raw water side in the three years I have owned her. Wouldn't it be time to loop a little muratic acid through the system? (or would that eat the impeller?)

GonzoF1 said:

Well, I haven't flushed the raw water side in the three years I have owned her. Wouldn't it be time to loop a little muratic acid through the system? (or would that eat the impeller?)

Click to expand...

There are folks who do that for a living and they would probably know best, but I think they just run the acid through the rest of the system (the heat exchangers and coolers) with their own pump and without running the engine.

GonzoF1 said:

Well, I haven't flushed the raw water side in the three years I have owned her. Wouldn't it be time to loop a little muratic acid through the system? (or would that eat the impeller?)

Click to expand...

We haven't flushed the raw water side of our cooling system in the 14+ years we've owned the boat, and we've not had anyone in the marine diesel business say we should. The waterflow out our exhausts is unchanged since we bought the boat. Well, actually, that's not true. It got stronger when we got rid of the stock Jabsco pump/Lehman drive coupler setup and installed larger Johnson pumps.

Phil Fill said:

With the Deep draft we have some close to the bottom ...

Click to expand...

ROFL ... considering your draft is only about 12 inches more than a little GB that's 22 feet shorter I think your "close to the bottom" experiences were related to something other than "deep draft."

Marin said:

We haven't flushed the raw water side of our cooling system in the 14+ years we've owned the boat, and we've not had anyone in the marine diesel business say we should.

Click to expand...

It all depends on where the boat lives. There are places where flushing the raw water side every couple of months is all but mandatory.

RickB said:

It all depends on where the boat lives. There are places where flushing the raw water side every couple of months is all but mandatory.

Click to expand...

And those places are ................................... ?

And the reason is ........................................ ?

I think it's more common to flush engines that don't use a heat exchanger but pump salt water through the cooling jackets of the engine. I have never flushed my engine. I did replace the heat exchanger once in twenty years.

Considering how much slim builds up on the bottom of our boat in the river where we reside, I suspect there is a certain amount of that goo in our heat exchanger that needs flushing out.

rwidman said:

And those places are ................................... ?

And the reason is ........................................ ?

Click to expand...

Parts of south Florida for one. Marine flora and fauna in the sea chests and heat exchangers.

RickB said:

It all depends on where the boat lives. There are places where flushing the raw water side every couple of months is all but mandatory.

Click to expand...

Good point. I have not operated boats in warmer waters (the ones I fished and sailed on in Hawaii were not mine so I was not involved in their maintenance). So I tend to think only in terms of our colder water with shorter days half the year.

There are two primary reasons to flush a boat's engine or cooling system:

1) Raw water cooled engines, if operated in salt water, should be flushed with fresh water and perhaps a salt reducing product after each use if possible, but in any event, as often as possible and before storage. This flushing prolongs the life of the engine, especially the manifolds and risers.

2) Fresh water cooled engines (closed cooling system with anti freeze in the engine) may need their cooling systems (heat exchangers, oil coolers, etc.) flushed from time to time with acid or other products designed to kill and remove marine growth. The same appies to air conditioning systems.

The product featured on ShipShape TV and mentioned by the OP seems more suited to a raw water cooled engine on a boat that's kept in the water and not easily flushed. Most of us with closed cooling systems don't need to flush the heat exchangers, etc. after each use and that product isn't suited for acid cleaning.

Depends on the engine.

My experience with raw water cooled is limited to outboards, a Yanmar YSE12 that was in my first sailboat and a Volvo gasser in a 19 ft speedboat.

My current outboard, a Honda 40, needs to be flushed. I found tis out the hard way.

The yanmar was installed in 1977 when I built the boat. I sold in 1988, never flushed and never a problem. Talked to the current owner in 2007. He worked at Yanmar and put in a new engine that year. When he inspected the old engine, after 30 yrs, he claimed the water passages were all clear.

The gasser lived on a trailer, so to protect from frost, it got flushed and drained regularly, so I don't know how well it would have fared without.

I have never flushed the fresh water side of a heat exchanger. When I cleaned the HEs this year, after 12 years, one engine HE and trans HE needed it, as the salt scale was building and partially clogging some of the small pipes. The other trans HE was almost perfectly clear and that engine runs cooler than the one done first, so I haven't done it yet.

flushing with acid is no substitute for removal and inspection. I have found all sorts of debris in teh HE end caps. broken zincs, bits of impeller, lumps of mush. A blind acid flush won't get rid of all of that.

The product featured on ShipShape TV and mentioned by the OP seems more suited to a raw water cooled engine on a boat that's kept in the water and not easily flushed. Most of us with closed cooling systems don't need to flush the heat exchangers, etc. after each use and that product isn't suited for acid cleaning.

Click to expand...

Why is that? No one is talking about circulating pure hydrocholoric acid throught the thing, though that would work great. I figure if a chemical won't kill you it isn't strong enough to do a good job.

Strainers are used for more than just engines ... A/C cooling water for one, washdowns, etc. There is nothing wrong with fresh water flushing a seawater circ system.

RickB said:

......... No one is talking about circulating pure hydrocholoric acid throught the thing, though that would work great. .......... .

Click to expand...

The OP asked about that very thing in post #5. And no, it wouldn't work great for that unless the plan was to run acid through it, the cooling system, and out into the sea.

A better plan is to disconnect the hoses at both ends of the cooling system and recirculate the acid throughout the system with an external pump and then recover the acid and dispose of it properly.

Hmm... didn't think about the flushing acid out to sea part... Ooops. maybe I need to engineer a circulating pump rig myself for it. Good point. Thanks.

The story also said it can be used as an emergengy bilge pump, but the effectiveness of it and the ability to deploy it under conditions when you need it are very questionable.

I may end up with it anyway should the price be in the range. Current one does need replacing and relocating.

Tom-

Most engine manufacturers will recommend the heat exchanger and intercoolers be cleaned at some regular interval, and that can be higher or lower depending on the waters the boat is in. In the southeast, for the most part, the heat exchangers should be checked, and cleaned if necessary every time you flush the freshwater system per the engine's PM schedule. These guys have a great product and will even sell you a set up to DIY that will also do your air conditioning system, though a similar kit can be made very cheaply by a handy person. I generally have the flush done and clean done by a mechanic as part of a broader "check up". Maintaining the cooling system is one of the critical PM requirements for diesels; failure due to over heating is invariably catastrophic.

Barnacle Buster

GonzoF1 said:

The story also said it can be used as an emergengy bilge pump, but the effectiveness of it and the ability to deploy it under conditions when you need it are very questionable.

Click to expand...

Not really ... just rig up a non collapsible hose from a strum box to the hose connection on the strainer and it's done. If you need emergency bilge pumping through the raw water pump all you have to do is change over the valve on the strainer and voila - you are pumping the bilge.

It is a standard setup on big ships. On steamships we could cross over the main circ pump to the bilge and remove about 25,000 gallons per minute.

True, Rick, but in an emergency situation, I see the idea of moving the engine room floor panels and jumping into a flooding bilge full of dark water and no light while fumbling around in the water on top of a running engine (that is IF the engine is still running) trying to flip a valve to CITY as the best use of my time. Moreover, if there is a hole big enough to allow in the amount of water it would take to NEED to deploy such a system, I would think I would need to be trying to save lives by getting them into the lifeboat or on the bridge trying to get her up on a sandbar.

But that just me. In the rare possibility it COULD be needed... it might be a nice option. I just don't see it as a very easy or smart thing to use as an emergency device.

One of the things the captain of the 120' corporate yacht I was associated with for a bit did was to have every seacock and critical valve handle on the boat wrapped in silver reflective tape. That way, he said, if someone had to enter a space to find and shut off a valve and the power was out on the boat, the beam from a flashlight would make these handles stand out like sore thumbs even underwater. He demonstrated this to me once in the engine room (but not the underwater part) and it was impressive. I vowed to do this on our own boat but of course have not gotten around to it yet.........

GonzoF1 said:

True, Rick, but in an emergency situation, I see the idea of moving the engine room floor panels and jumping into a flooding bilge full of dark water and no light while fumbling around in the water on top of a running engine

Click to expand...

Hmmmmm, I see it more as you notice the bilge pumps are running and the high water alarm comes on.

You open the engine room hatch, there's no reason it should be dark, and turn that big handle on top of the strainer to select the bilge suction then head for the beach or another boat, or try and deal with the source of flooding.

If the boat has flooded to the point the batteries are underwater and the engine has quit there isn't much point in opening the emergency bilge suction anyway is there?

That's all true... But I panic easily ;-)

The OP questioned the wisdom of connecting a dock-hose to the engines' raw-water strainer. I had similar concerns when planning a fresh water flush system for my engines and genset: (a) would a hose supply enough water for an engine at idle? and (b) could I flood an engine by inadvertently leaving the hose running after switching off the engine? I decide that the answers were probably "no" and "yes". I ended up installing an old (clean!) 12 gallon plastic holding-tank in the bilge under the generator with piping and valves to suit. I can now run each motor in turn on fresh water and watch the water-level in the tank drop - it doesn't take long. I refill the tank with dockside water or through a dedicated line from the boat's supply, depending on what's available. The engines and genset suck water up from the tank, so there is no possibility of flooding a motor with pressurised water.

FWIW I timed how long the engines and genset each take to empty my little tank. Each engine (160 hp Yanmar 4LH-DTE's) uses around 20 gals/min at idle and the 6Kw genset uses around 12 gals/min. This suggests that a standard hose probably could not meet the demand of either.

I'm a big advocate of being able to pump your bilge with your engine cooling pump. That said I don't think the Perko 0593 strainer is the best way to do it. The problem is that you are limited to about a 3/4" intake hose for the bilge. That's fine if your engine uses a 3/4" pump but if yours is bigger, you lose pumping capacity.

It's a great way to flush your engine and certainly better than nothing when it comes to bilge pumping.

Another option would be to install a Groco SSC Flush Adapter on your seacock.
This allows you to flush your engine and in an emergency you have the full pumping capacity of your engine.


[FONT=Arial, Helvetica, sans-serif]Add an SSC to the top of any seacock to allow instant emergency bilge pumping, or to simplify winterization and cooling system flushing.[/FONT]
[FONT=Arial, Helvetica, sans-serif]IN AN EMERGENCY: While the connected engine is running, close the seacock and remove the quick release plug. Excess bilge water will be pumped overboard by the engine raw water pump. Add GROCO Bilge Strainer to pump out remote bilge locations. See Illustration[/FONT]

Another issue with using the engine(s) as bilge pump is that someone has to be there monitoring it. If the water is coming in at a rate slower than the engine's pumping capacity, you have to switch it back to seawater cooling and then back... while trying to find and mitigate the leak. Engine likely to be running full speed towards land. Good to have at least three people on board. Some sort of purpose built crash pump which can also help in case of fire is preferred (say the water hasn't reached the engine room yet), but why not have the capacity if you can?

caltexflanc said:

.............. If the water is coming in at a rate slower than the engine's pumping capacity, you have to switch it back to seawater cooling and then back........

Click to expand...

And if you don't your engine overheats and the impeller melts. Now you have a sinking boat with no engine. Not Good.

A 110V submergible commercial trash/crash pump with an adequate run of discharge hose (3" ID or so) allow one to pump water from any of your your bulkheaded areas. On our vessel we have 4 areas, each with its own potential leak spot. Provided you have a genset or larger inverter this may be worth considering. You can go as simple as a pool or basement sump pump or upgrade to a commercial mud pump.

psneeld - If the USCG or a "rescue tow boat" show up to pump your sinking vessel what portable pumps do they use?