Are manual bilge pumps useless?

Surely it is not a question of either/or. If things get serious you want to have as many means as possible to shift water. For me that means electric and manual bilge pumps, the engine water intake switchable to a pipe with strainer in the bilge, the shower sump pump and a bucket. And if going long distance I would add a big movable manual pump with long intake and outflow pipes to be able to use it away from the bilge if need be.
 
Just chuck it through the main hatch and let it drain through the cockpit drains. This would be quicker.
Minn said:
I suggest that you try it.

A full bucket holds about two gallons but a bucket in use may hold one. You now have to get your bucket from the bottom of the boat, through the companionway, across the cockpit and into the sea.

You will be doing well if you manage two gallons a minute. Now keep it up for an hour.

Come back and tell us about how you did the job faster.
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A bit of a daft question really I believe. If it's all you've got after the rising water shorts the battery terminals, then having 'been there' (more than once lol), then I promise you won't see them as "useless":)
 
There are real issues related to using the engine seawater pump as a bilge pump.
They don't self prime very well. It may stop working every time it sucks air.
Your engine may not work.
If your yacht is knocked down, you would be optimistic to expect the engine to not miss a beat.
You'll use lots of diesel if you need to keep pumping a long time. Especially at the high rpm you need to get a good flow rate.
Better to have an electric pump and charge the batteries part time.

Luckily most boats have manual pumps. It would be a strange idea to remove them instead of adding an electric pump or two as backup.

Buckets only work when it's desperate, like 6 inches of water at large in the boat. On a small racing dayboat, that's survival, on a 30ft yacht that's a destroyed interior. A bilge pump will work to spec on an inch of water in the bilge. Less if the boat is well designed.
 
A bilge pump is not really a piece of emergency/safety equipment at all. If the boat is taking on so much water that there is danger of sinking then the sort of bilge pump typically carried is not going to make much difference.

The engine intake even less - I winterise my engine by diverting the intake into a bucket and it gets through about half a gallon a minute (at idle)
 
I had similar experience as was mentioned earlier in this thread, water pump on engine broken so plumbed into the hand pump. 30 foot boat 14hp engine and it only required very slow pumping to keep normal flow of water through engine. So I am pretty sure a good diaphragm hand pump is far more efficient than an engine cooling water pump.. just look at the size of the hoses.
As for buckets, after my father had a very rough trip across the mouth of the thames in a Silhouette (17'6") when I was a kid he told me they were taking a lot of water and I said something about the bilge pump (brass things in those days). He said "nothing moves water as fast a frightened man with a bucket". I always keep a good bucket on board, it kind of depends on how much water you are looking at.
 
pvb said:
You may be surprised how little water is pumped through the engine. Try putting a bucket under the exhaust and seeing how long it takes to fill.
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Indeed, it depends a lot on the engine, I used to do a flush of my MD7a with a bucket of fresh water and some additives, it took a good 2 or 3 minutes to shift a bucket full.
 
bedouin said:
A bilge pump is not really a piece of emergency/safety equipment at all. If the boat is taking on so much water that there is danger of sinking then the sort of bilge pump typically carried is not going to make much difference.
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I would imagine that sometimes you just want to buy time rather than save the boat.
 
After reading all the posts above, I think that the question lies in :
when does one really have to use a manual bilge pump???

answer :
when all the other BETTER means to pump out water are non available,
AND when the leak is small enough to be controled with a manual pump (low outflow rate),
AND when you can't plug the hole/leak....

it's a lot of conditions for someone to end up using a manual pump...
 
alexlago said:
So I really wonder about the real use of those manual bilge pumps...
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And if you do ever suffer a loss, and if don't have a manual bilge pump? Your insurance provider can look back on this thread, as you've appeared to use your real name.

Certainly was a policy condition on a previous boat, don't recall if it is on this boat's policy, but as I have a manual anyway, a Henderson Mark IV, it's a moot point for me.
 
alexlago said:
After reading all the posts above, I think that the question lies in :
when does one really have to use a manual bilge pump???

answer :
when all the other BETTER means to pump out water are non available,
AND when the leak is small enough to be controled with a manual pump (low outflow rate),
AND when you can't plug the hole/leak....
Click to expand...

And when the volume or ingress of the water you need to clear would benefit from the output of all the pumps you can put to the task.
 
There is no way I could use a bucket to empty any meaningful volumes of water out of the bilges. The level would need to be much higher to do this.

Tests in the past have indicated far better endurance from a well positioned manual bilge pump compared with a bucket.

Lose your electrics, and manual becomes the only option. Enough water ingress and you may well have no engine or electrics. It does not have to be a fast ingress - just need time to let the water in. Imagine turning up at your boat only to find the floor boards floating due to a stern gland failure, and your batteries shorted.

There are good reasons why yachts are built with manual pumps.
 
alexlago said:
After reading all the posts above, I think that the question lies in :
when does one really have to use a manual bilge pump???

answer :
when all the other BETTER means to pump out water are non available,
AND when the leak is small enough to be controled with a manual pump (low outflow rate),
AND when you can't plug the hole/leak....

it's a lot of conditions for someone to end up using a manual pump...
Click to expand...
That's complete tosh basically.
A lot of yachts will go through long lives without ever needing a bilge pump.
But when you do end up with 20 gallons of water in the bilge, the permanently installed manual bilge pump is often first choice to deal with it. Electrical failure is not that rare on boats. Electric bilge pumps are not the most reliable things. Did you ever wonder why there's so many of them in chandleries? It could well be related to the fact that everyone I know who uses one, I mean uses it, not just has one in the bottom of a dry boat, seems to buy a new one every year or two. That includes a lot of RIB owners as well as people with open or wooden sailing boats.
By all means, don't plan on using the manual bilge pump, I don't plan on using either of ours, because we don't plan to get more water in the bilge than can be dealt with by a j-cloth. But they are there, and they're tested and known to work. As are the buckets and the electric bilge pump. And the shower drain pump. None of this would save the boat from a really big hole below the waterline, but that's what the liferaft is for. It's more likely a yacht will get a small hole, knocked down, waves over the companion way, a failed hatch or something. All eventualities any decent boat is prepared for, without 100% relying on electrics. I've not often needed to pump the bilge of a cruising yacht (stanchion leak, water tank problem, big spinnaker braoch...) but I've seen enough electrical problems to want a manual pump or two just in case. Since we dabble in the odd race, it's not open to question, we have two and that's that.
 
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