Emergency Pumps

[CDreamer]

Over in General Discussion, louTribal has a recent post that includes a short discussion about his engine's PTO. That made me think of using PTO's for large pumps. This reminded me of this story from the very well-written and informative blog by the owners of M/V Dirona. This couple is extremely experienced, and quite technically advanced. Their Nordhavn is clearly shipshape at all times, as they make ocean passages all the time. You can Google "M/V Dirona" for more - they cover many subjects that I find useful.

Anyway, this particular story is worth a read. The 'real world' of dealing with a significant water leak with only two people aboard. Would YOU be prepared for this? How many of us have never had to put our pumps to the test?

I hope the link works...if not you'll have to cut & paste it.

Alarms at 1:15am – MV Dirona

 

[psneeld]

Good read...

But for the 90 percent of us who coastal cruise, expeiencecing conditions like that should be a once or twice in a lifetime event.

Not being able to contend with with less than cockpit filllng seas is unusual for many of out vessels. 3000gph worth of electric bilge pumps installed properly will evacuate a lot of water as long as your boat is shedding it well.

 

[twistedtree]

As far as the pumps are concerned, the underlying problem was a rusted out rivet in the Jabsco main bilge pump that rendered it unable to pump. A steal rivet holding a salt water diaphragm together. What is Jabsco thinking? This is a very common problem with those pumps. Lots of people are switching over to the Whale Gulper.

But back to your point, periodic flooding and testing of your pumps and alarms is a good idea. Note to self: get off your duff and do as you say . I've checked my Jabsco diaphragm pump recently, but not the myriad of other high water, high flow pumps.

 

[Roamer Blue]

Hypothermia plays a big role in dumb thinking, something the author does not mention.

Hypothermia can play a part in poor thinking even in Great Lakes boating during the summer.

Headgear is a critical tool. This ain't a fashion show.

A regular boring fur hat with some sort of poly/vinyl outer coating will keep your head warm, even when wet. Leave the chin straps on it, or add them to keep the ear covers tight to your noggin. Bass Pro and friends sell 'em every year.

Cheap and easy.

RB

 

[CDreamer]

Emergency Pump 'sidebar'

For context related to the Hamiltons and their bilge pump story, this video provides a sense of what I'm willing to admit is their "above average" level of shipshape-ness. Of course, the boat's not 30 years old either.

 

[Xsbank]

It fills me with wonder to see that photo of that couple, standing there blissful on their elaborate and expensive brand new boat that has such a fundamental flaw. And shame on you Jabsco! Why is it that we have the capability to make toasters that last for 50 years but despite the prices demanded, can't produce a reliable pump? No wonder we are all doomed. I'll save a spot for you in the catacombs...

Even an emergency pump that can lose its prime? Holy crap!

 

[twistedtree]

I think pretty much all crash pumps require priming, including the ones the CG passes to you as your boat is sinking. I think you basically have two design choices. You can use contact rubber impellers like an engine seawater pump. They self prime and will lift water some distance, but they won't last if run dry,and then become useless. Or a non contact impeller which can lift a good distance, but only after priming.

The later style often retain enough water when shut down to prime the next start. So in a sense they are prime-once pumps. The trouble is, if left for an time, the water evaporates out. The Hamilton's came up with a good pre-prime technique which is to fill with rv antifreeze which doesn't evaporate off. Then the pump is ready to go.

 

[ksanders]

Another option is a submersable pump.

The one i just bought does 80gpm at a 5' head.

 

[CDreamer]

This is another good story from the Hamiltons. Long, but good insight, and some details about the capacity of their pumps.
(They very rarely have trouble, but they are willing to put themselves out there when something goes wrong). As psneeld said earlier, 90% of us won't ever be in these situations. We stay in the ICW or a river or a bay, but they travel the world's oceans. Over 13,000 NM at sea when this was written.

http://mvdirona.com/2014/09/69-1-degrees/

 

[Lepke]

Engine driven pumps usually have a small line from raw water exhaust that is always on, so prime isn't an issue with a centrifugal pump. They commonly have a valve to the sea so they can double as a fire pump. Some boats use valve stem linkage so they can be operated outside the engineroom so fire fighting water is available even with a fire in the engineroom.
No offense meant, but 3000 gpm would be useful with a damaged hull. 3000 gph isn't much. Add in the effect of hose, bends and discharge port and it might handle a large hose coming off.

 

[Lou_tribal]

I learned the hard way how much important it is to have your pump working in my recent experience. For those that did not read my post on this, on our departure for our cruise 3 weeks ago, a raw water hose popped out on the exhaust manifold and the engine was pouring water in the ER. I notice the issue immediately hearing the exhaust noise without water. Checking the ER I saw 2 feet of water, jumped to force the pumps on (no time to check if they were already started by the float switch), and turned back.
I was very thankful to see that the pump was working and keeping water level low and the boat afloat.
Lesson learned:
1. Periodically check and exercise your pump.
2. Always give a check on hose clamps before departure.
3. Open the 2 ER hatches in an emergency situation (so I could have notice that the hose under the other hatch had popped out )
4 Never, ever, in no circumstance, allow the marina mechanic to approach my engine by less than 10 feet if I am not aboard.

For using the PTO for a pump, I think an simplest setup is to use the engine to pump raw water from ER with a similar result. Of course you always have the situation of something blocking the water intake but I guess that considering the hose diameter and going through the strainer would limit this.

L.

 

[twistedtree]

This is another good story from the Hamiltons. Long, but good insight, and some details about the capacity of their pumps.
(They very rarely have trouble, but they are willing to put themselves out there when something goes wrong). As psneeld said earlier, 90% of us won't ever be in these situations. We stay in the ICW or a river or a bay, but they travel the world's oceans. Over 13,000 NM at sea when this was written.

http://mvdirona.com/2014/09/69-1-degrees/

I'm pretty sure it's 13,000 hrs on their engine. Their sea miles are considerably more than that. Heck, they are pretty much circled the globe. I've done 11,000 miles on this boat, and they are WAY ahead of me.

 

[psneeld]

In my experiences, there are 2 ways to look at bilge pumps during emergencies.

One is ......internal emergencies like evacuating water from a hose leak, failed through hull, water coming aboard from spray or waves.......not damage control. Generally 3000 gph done well, not installed poorly, and actually working will often suffice on smaller boats say below 50 feet. Having more as back up or quickly drying out a boat with a major hose issue isnt a bad thing either.

When you talk damage control, most here really have no clue what it will take pump wise to keep a boat afloat in perfectly calm conditions with a hull breach. View a couple salvage jobs and see the patches necessary to keep water out and the massive amount of pumping required. Beating the ingress of water after the patch is applied is often a scramble to win the battle.

Damage control is about slowing the ingress of water so the pumps can win, no matter how big or small the pumps are. Damage to the hull at sea can result in water ingress that even trash pumps whether separately powered or by a PTO cant keep up with. Good damage control usually takes at least 3 people....2 if in a place where autopilot will work.....primary and a runner/helper.

For most small vessels with limited crew, if you cant identify the source of water ingress and slow the leak to a large trickle very quickly, better plan on at least 2 large trash pumps and maybe more. With as many people who complain about spaces on their boats that are hard to get to or their physicsl limitations dont allow them to get intobpkaces wuickly or at all....damage control may be moot. Maybe thinking proper abandoning ship procedurescmay beca better usevof time than losing the sinking battle and being ill prepared for water entry.

Having been in the salvage business and the rescue business, I am all for being prepared.....and more pumping capacity the better. But as many know, don't have the emergency first off. Good maintenance for on board emergencies, work hard at not hitting things with your boat that can hole you, know and be ready for basic damage control, have early warning detection for flooding, etc...etc....and know when its time to switch from damage control to abandon ship.