Groco SBV Emergency Seacock

[American_Mainsail]

SBV-1250-P 1-1/4" Flanged Seacock with Side NPT Port| GROCO

I'm thinking about doing an install of one of these. These special seacocks are a cool concept. The idea is that the engine seacock has a 1" NPT port in the side that allows it to be plumbed to a pickup in the bilge. In the event of an emergency, you can turn your engine into a crash pump that sucks water from the bilge instead of the thru-hull.

Problems:
After a phone call with Groco, I confirmed that the valve handle can be positioned in a way that turns on both the thru-hull and the port, allowing water from outside to flood the bilge (potential sinking hazard). The 1" inline valve off the port would prevent this from becoming catastrophic since the valve would *should* always be closed unless actually using the crash pump feature, but overall, this setup significantly complicates the engine seacock picture.

Groco makes a very cool locking 1" valve that could essentially eliminate the issue of inadvertently turning the crash pump port. The locks makes it so that you have to deliberately work to turn this valve on.
IBVL-1000 1" NPT Bronze Locking Valve| GROCO

Your thoughts?

 

[BAD ORCA]

SBV-1250-P 1-1/4" Flanged Seacock with Side NPT Port| GROCO

I'm thinking about doing an install of one of these. These special seacocks are a cool concept. The idea is that the engine seacock has a 1" NPT port in the side that allows it to be plumbed to a pickup in the bilge. In the event of an emergency, you can turn your engine into a crash pump that sucks water from the bilge instead of the thru-hull.

Problems:
After a phone call with Groco, I confirmed that the valve handle can be positioned in a way that turns on both the thru-hull and the port, allowing water from outside to flood the bilge (potential sinking hazard). The 1" inline valve off the port would prevent this from becoming catastrophic since the valve would *should* always be closed unless actually using the crash pump feature, but overall, this setup significantly complicates the engine seacock picture.

Groco makes a very cool locking 1" valve that could essentially eliminate the issue of inadvertently turning the crash pump port. The locks makes it so that you have to deliberately work to turn this valve on.
IBVL-1000 1" NPT Bronze Locking Valve| GROCO

Your thoughts?

It just seems like so much money. It seems like it would be much less complicated, and cheaper to simply buy or add a higher output bilge pump. With lithium now and a decent size reserve bank, you can run bilge pumps for days, especially if your alternator can keep up with the electrical demand of all your pumps. If your engine dies that Groco valve feature is useless, but the battery bank could still work and run the pumps buying you some time. If you have bilge pumps on the common post of a battery switch and your primary battery bank dies, you could switch to bank #2 and run the engine/alternator to keep the pumps running. This is one reason i think the on/off battery switches are inferior to the 1-2 switches unless they have a common post. All that being said, I can envision particular use cases where it might be valuable. For example, not everyone can afford, or has space for multiple large lithium banks, or does not yet have them. Redundancy is a good thing though, but for $600? I would prefer to add another pump and/or battery for that price.

Would also love to hear other thoughts.

 

[MFD]

I have read in a few places that the actual amount of seawater that say a 4 cylinder Yanmar actually moves is very low, and thus a solution like this is not worth the effort/risk.

A pump driven off the shaft with a clutch or something, entirely different deal and would be able to move a huge amount of water. Most sailboats don't have space for something like that though.

 

[FastOlson]

If you watch the amount of sea water that exits via your wet exhaust, note that this is usually not a lot in "gallons per hours" measurement, and also note that this water is carefully strained via your sea water strainer before it gets to the small angle fittings in your little raw water pump and then flows thru the small tube openings in your heat exchanger.
Suddenly trying to draw water from a flooded bilge contaminated with Poseidon-knows-what detritus from the insides of compartments adjacent to the bilge is a recipe for a clogged pump and a burned out impeller. Immediately.

For an auxiliary way to remove emergency amounts of water, it seems far better to have a large 12 volt pump in place that can run off of your battery bank that is charged by the alternator from your running engine.
My .02 worth.....

 

[dLj]

I prefer KISS systems. I'd rather have an emergency back-up high volume pump that can be deployed if needed. It can also be placed in different locations if needed.

On my current boat, I have a pretty high capacity bilge pimp, two manual hand pumps one accessed inside and one accessed in the cockpit. I also have a high capacity pump that I can place almost anywhere in the boat that runs off 12V.

I don't feel that added complication and cost for what you are proposing to be the best solution

dj

 

[MFD]

I have a 110VAC 1.2hp outdoor pond pump that is supposed to do 5700gph and associated 1 1/2” hose that can go out a cabin window. Did a dry run (pardon the pun) with it once and it moves far more water than the rule 500 and high bilge 4000 pumps.

The boat has two inverters, one a good amount above the cabin sole as are the batteries. The pond pump is not salt water rated, much less continuous use rated.

In all honesty in some kind of emergency situation I am not sure whether I would be trying to run the pump or beach the boat, or if offshore double checking the ditch bag and thinking about the life raft before the pump.

EDIT: And have never looked closely at it, but thought about it. The forward and aft shower pumps which are already diaghram pumps that deal with junk quite reliably would also be preferable before sending that water into my engine seawater system and risking a clog. Probably during a situation when I really need the engine to work when needed.

 

[dLj]

In all honesty in some kind of emergency situation I am not sure whether I would be trying to run the pump or beach the boat, or if offshore double checking the ditch bag and thinking about the life raft before the pump.

Kind of an aside in this conversation, but in my opinion your mindset should be to save the boat as primary objective, not looking for the ditch bag and life raft. Beaching the boat is a good option if available. I put that in saving the boat category.

But offshore - keep the boat floating.

dj

 

[Hayden Watson]

...

For an auxiliary way to remove emergency amounts of water, it seems far better to have a large 12 volt pump in place that can run off of your battery bank that is charged by the alternator from your running engine.
My .02 worth.....

I agree. The raw water pump on my Universal M25XP Is an N202M-16. It has a max flow of 12gpm at 3500rpm but under normal use, it would deliver much less than that. It is driven by the fuel injection pump which runs at 1/2 crankshaft rpm. My max cruise rpm is 2200 so the pump is turning 1100. At that speed, it will only put out about 5gpm or 300gallons per hour. I installed a Johnson 4000 gph pump for my emergency pump to back up my 2500ghp normal pump, so I have 6500gph for emergency discharge in two completely seperate systems. The Johnson has its own discharge hoses, ports, wiring, resettable circuit braker and float switch which is set 2" higher than the normal auto bilge pump.

My house battery is a 560Ah LFP and I recharge it with a 250A alternator which is a far better use of the engine in an emergency.

 

[American_Mainsail]

i just wanted to stop in to thank everyone for giving their thoughts on this.

My big takeaway here is that the capacity just isn't meaningfully there with a small, inboard diesel. A power boat running a (much) bigger engine might benefit from this system, but the usefulness is really limited by the relatively low water draw of a < 100 HP marine diesel.

In response to everyone's comments, I cracked open Gerr's Boat Mechanical Systems Handbook to get some recommendations for bilge pump/crash pump sizing. He has a great section discussing ABS pumping capacity requirements, and also, what he feels like is appropriate (which is considerably higher than the standards of when he was writing this book).

Assuming a very generous 1000 GPH flow rate of my 50 HP Yanmar, that number would satisfy the ABS and ISO requirements he lists in the book (which are admitedly old, but I'm not really taking these numbers to the bank), These numbers seem to be more aimed at nuisance water than emergency preparedness.

Gerr takes the approach of estimating flooding based on a small hole in the hull (a 2" penetretation leading to an actual emergency) and recommends the following formula:
Pump capacity (GPH) = 1,000 + 100*displacement (long tons)

For my boat, this would give a capacity of ~2,050 GPH. The size of my current bilge pump. I still feel that this is a little low, and Gerr gives a nod that it wouldn't be unreasonable to add additional capacity (up to 3 or 4 times the number above).

At the end of the day, spending ~$700 to outfit the boat with a 3000 GPH Rule crash prump and provide more flow capacity in an emergency.

 

[BAD ORCA]

i just wanted to stop in to thank everyone for giving their thoughts on this.

My big takeaway here is that the capacity just isn't meaningfully there with a small, inboard diesel. A power boat running a (much) bigger engine might benefit from this system, but the usefulness is really limited by the relatively low water draw of a < 100 HP marine diesel.

In response to everyone's comments, I cracked open Gerr's Boat Mechanical Systems Handbook to get some recommendations for bilge pump/crash pump sizing. He has a great section discussing ABS pumping capacity requirements, and also, what he feels like is appropriate (which is considerably higher than the standards of when he was writing this book).

Assuming a very generous 1000 GPH flow rate of my 50 HP Yanmar, that number would satisfy the ABS and ISO requirements he lists in the book (which are admitedly old, but I'm not really taking these numbers to the bank), These numbers seem to be more aimed at nuisance water than emergency preparedness.

Gerr takes the approach of estimating flooding based on a small hole in the hull (a 2" penetretation leading to an actual emergency) and recommends the following formula:
Pump capacity (GPH) = 1,000 + 100*displacement (long tons)

For my boat, this would give a capacity of ~2,050 GPH. The size of my current bilge pump. I still feel that this is a little low, and Gerr gives a nod that it wouldn't be unreasonable to add additional capacity (up to 3 or 4 times the number above).

At the end of the day, spending ~$700 to outfit the boat with a 3000 GPH Rule crash prump and provide more flow capacity in an emergency.

I think its also worth noting something that many people seem to overlook is to make sure your running engine and alternator/house bank batteries can keep up with the electrical demands of your pumps running full out for some given amount of time. 8000 gph of pumps running flat out could easily be in the 25-40 amp range. I guess everyone has their own answer for what this should be, but I would want all of my emergency pumps to be capable of running flat out for several hours minimum. I dont have the illusion the pumps will be able to keep up with a 2" hole in the hull forever, but I would hope my pumps would be capable of running long enough to give me time to stop the water flow. I figure, if i cant do that in under a few hours, i'm probably prepping the liferaft.

 

[BigEasy]

I had once considered the Groco fitting to supplement the designated bilge pump In an emergency situation. After reading y’alls analyses, I agree that your efforts ( and money) would be better spent on increasing pump capacity. Little to be gained from the Groco fitting.

 

[FastOlson]

Even the conservative "Category One" offshore racing requirements requiring a big manual pump operable from the helm position, do emphasize that all your pumping efforts are aimed at slowing the ingress while your crew stops or at least drastically slows the leak. Pumps buy you time!
A friend of mine recently had a major leak, and the USCG provided a gas pump unit that did indeed keep up with the water coming in until the boat got to the slings in a nearby boat yard. I do not recall the exact hose size but it was somewhere around 3 or 4 inches. His boat's electric bilge pump worked hard, but could hardly slow the rising waters.
The rule about having a plug adjacent to every thru-hull is a good one. Note that it is normal for offshore boats to carry some dunnage and at least have a plan for which soft goods to stuff into a hole. I suspect that only a fractional % of us have ever had any training anywhere close to what the Navy or Coast Guard gives sailors in real "Damage Control" school where they learn to do these procedures in a room/compartment on shore, with water flooding in at a high rate.
(No, I have not done that, but a friend in the USCG did. He said he never forgot the urgency of dealing with fast flooding, with water rising quickly to his waist!)