Shock Then Awe - Emergency Bilge Pump

So I lifted all my ER floorboards today and gave them a thorough washing on the dock and then went in and started on the ER floor. cleaning those and replacing the diapers.

I then saw this "through hull" from the top and saw that it didn't have a valve! Well thinks I, that ain't right, and not what I expected on this boat from what I have seen so far.

Then I took a closer look, and saw from the side that it does not go through the hull after all but is raised up!

Ahah! I think I know what this might be! I followed the hose and sure enough it connects to the RW feed for the starboard engine on the engine side of the strainer and has a valve. By fully opening that valve and fully or partially closing the strainer valve you manage the water intake of the emergency bilge pump.

I have heard of the theory of disconnecting an engine RW hose when in dire straights - but had never seen a permanent set up like this.

When I was post processing the photos I also noticed the label!

Neat!

I like the concept, but it will just slow down your sinking event. Because it may run the engine impeller too dry and burn it out, then you have no pumping.

sdowney717 said:

I like the concept, but it will just slow down your sinking event. Because it may run the engine impeller too dry and burn it out, then you have no pumping.

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I think the idea is to keep the RW valve open to the extent that both are working.

Regardless, I am not sure I would want someone sitting in a flooding ER watching it! Though this is right by the door into the master cabin so no need to be in the ER once the valves are thrown.

I did a rear seal on a c32 in a 60ft sport fisher that had basically the same setup only bigger. 4" iirc. Looked like it would move a good bit of water if needed but I would not want to be in that engine room if it was taking on water. It was stupid tight getting in/out under perfect conditions at the dock.

Last year a delivery captain hit a submerged obstruction and knocked the strut up into the bilge on a 50 ft Sea Ray. He saved the boat by disconnecting the rw hose and used the port engine as a crash pump. I was impressed

I guess its a nice to have add-on, I can't think of any downside. Not sure whether the flow rate would be all that high though.

Was reading this the other day about going through the wide bay bar in silly conditions
https://mvdirona.com/2014/09/69-1-degrees/

Hydraulic pumps are impressive
180 gallons/ minute impressive
https://mvdirona.com/2017/04/fighting-water-ingress/

Surprised it doesn't suck the whole boat in and spit it out. ( -;

Just monitor it as it is pumping and if the level approaches the crash pump inlet as the water hopefully goes down then open up the thru hull inlet so that the raw water pump does not burn out the impeller. You may have to open an close it as the water goes up and down.

Insequent said:

Not sure whether the flow rate would be all that high though.

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Probably around 150 LPM I would think

I have a similar setup except that the valve is between the valve is on the intake side of the strainer.

L

Same here, except they are both generators, not the engines.

I'm not impressed. In a flooding engine room all manner of stuff is going to get sucked around the strainer on the end of the hose. For it to be long-term effective, the strainer should probably be the size of a 5 gallon bucket. If you need that much pump, there will be bits of broken hull floating about. Also, once you hole the hull, you may find debris coming in from outside.

Ted

That’s almost identical to the set up I installed in my boat. I only had an 1-1/4” Pump. I figured it would move about 1500 gph. If your boat’s sinking, you want all the pump capacity you can get.

We have the same setup on both of our engines, factory installed. Hope to never need it though.

If it fails, what the heck, it's going to sink anyway.

Comodave said:

Just monitor it as it is pumping and if the level approaches the crash pump inlet as the water hopefully goes down then open up the thru hull inlet so that the raw water pump does not burn out the impeller. You may have to open an close it as the water goes up and down.

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If you have this solution on your boat, I suggest you practice using it at the dock some time after a day's run. On most boats, opening up the raw water strainer wil let in plenty of water if it is below the water line. Then imagine doing it in a seaway.

Get back to us on what you learned. Thanks in advance!

My boat has a engine driven clutch pump that can be used for fire fighting or by turning a valve will scavenge water via a manifold that has 2 inch copper pipes running to each of the 4 water tight compartments.

caltexflanc said:

If you have this solution on your boat, I suggest you practice using it at the dock some time after a day's run. On most boats, opening up the raw water strainer wil let in plenty of water if it is below the water line. Then imagine doing it in a seaway.

Get back to us on what you learned. Thanks in advance!

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I don't think he mentioned opening the strainer - just the valve for the RW feed, which can be fully or partially opened. I don't see an issue with this while underway, unless I am missing something.

menzies said:

I don't think he mentioned opening the strainer - just the valve for the RW feed, which can be fully or partially opened. I don't see an issue with this while underway, unless I am missing something.

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I am just saying, go ahead and practice using the engine RW pump to handle a large flow of water, rather than learning it in an emergency. You can duplicate the heat and noise and ergonomics at the dock after a day of cruising, and then imagine doing it when the boat is rocking. On most boats, the rig is right near the propellor shaft, a dangerous thing to be near when rotating. I suggested the strainer opening (if it is below the waterline) as a way of duplicating a big leak.

I know a guy who had to use one of these underway, and it did save the boat. Not a friend-of-a-friend story, this guy is in the next slip and I've known him over 15 years. I've spent a lot of time on this boat and know every system inside and out, including the emergency engine raw water intake he ended up using.

Scoff if you will. I think it's a great idea. The pictures show a very well done install. I like the way the strainer is mounted low to the hull, so it gets all the water and is much less likely to clog with debris. Even if you had to get wet reaching down to sweep some debris away once in a while, it's better than treading water.

Our single diesel is keel-cooled so this isn't an option for us. We do, however, have a high-capacity washdown pump that discharges via a 1-1/2" line into the open rear cockpit, a leftover from her original life commercial fishing. This has a similar valving arrangement and a large strainer in the bilge.

"This has a similar valving arrangement and a large strainer in the bilge."


Nifty when the strumbox (strainer) is on a flexible hose with a rope attached, so it can be lifted and cleared easily.

I have a simple bronze valve that bypasses the raw water hose and connects to a length of hose with a SS strainer. I use it primarily to flush my engine with a few buckets of fresh water after use. Yes, it could also be used in an emergency.


CDK