Bilge Pumps Versus Holes In The Hull

[Mr B]

As the water came up in my sinking boat, 34 foot Cat,
My lead acid batterys were getting covered in water,.

WOW, Thats some display of fireworks, Nothing I could do about it except watch,
I had flames leaping out of them,
Then the water covered them completely and they shorted out and that was the end of that,
A very big relief to me,,
But I was worried that I was going to have a big fire inside the boat as well as sinking,

[psneeld]

Many batteries go under salt water without issue.

Several dozen boat I have helped salvage had the bilge pumps still running off the batteries the next morning when we raised them.

No guarantees but it is interesting g why some survive and others dont

[Omatako]

Originally Posted by basssears;2165604-

. Otherwise, I'm looking at a few different sized wooden plugs, a Forestar Sta Plug, and a hammer at EACH through hull... I'd rather have all my equipment consolidated just like a ditch bag, that way I have everything I need.

Where I live, a CAT1 inspection REQUIRES a soft wood bung attached to EACH seacock. So when I suggested to an inspector that if I in any case had to go back to the tool locker to fetch a mallet, leaving all the plugs where the mallet is made more sense, I got a "stunned mullet" look. In addition, I have three same-sized seacocks alongside each other - you guessed it, I need three identical plugs at that location! Really? One unprovoked seacock failure is already a stretch, two at the same time?? Ridiculous. But that is bureaucracy work.

On a different point, whilst I get the scientific evaluation of how much water will enter the boat with a seacock failure, reality is that there is really very little pressure. I had a galley seacock shaft break in the open position while trying to remedy a failed hose. A 2" stream entered the boat. I removed the remains of the seacock off the skin fitting (along with the wooden plug tied to it), used a stout plastic bag pulled over the skin fitting and secured it with a hose clip, all the while holding my hand over the "hole" between operations.

We were in an achorage 40nm from home and at the start of a two-week cruising holiday. We continued with our holiday and when we got home, I bought a new seacock and hose, removed the plastic bag, screwed the seacock onto the skin fitting and installed the new hose. The whole event saw maybe 10 gallons of water enter the boat.

What I'm getting at I guess is that if you're on board, a broken seacock is not a death sentence for your boat. It's actually not even a real emergency. If you're not on board, no amount of fancy pumps are going to make any difference, your boat is going to the bottom. That's why I hold fully comprehensive insurance.

[Dockhead]

Originally Posted by Cheechako

Yeah, always thought it was a waste of time and money. Very little reward for that. You can buy a Honda gas pump that puts out a steady strong 1" stream pretty cheap if you want a power pump. I think they are $550-600

Gas pump is nice for being completely independent of any other power supply.

However, they have two huge disadvantages:

1. You can't store them inside the hull volume due to fuel vapor risks, so where will you store it?

2. Small gas engines are notorious for not starting if they don't have fresh fuel, are not used regularly, carb drained between uses, etc., etc. Are you going to have time to deal with all of that, for an item of gear you will (you certainly hope) never use in anger?

I'd much rather rely on an engine I'll be using anyway for many other purposes, either main engine (pulley driven Jabsco with magnetic clutch) or generator (230v electric trash pump, my own choice).

[Rorzech]

Originally Posted by Dockhead

Actually "seacock simply falling off" is not all that rare. The problem can be caused by dezincification of the through-hull tail. A lot of mass produced European boats now have ordinary brass (not DZR brass or bronze) through-hulls, which bizarrely fulfill the CE standard requirements, and which are particularly susceptible to this problem.

Tapered softwood plugs are intended for that problem, or to plug any hole which you might need to plug in an emergency. It's a good idea, and like most sailors I carry a good selection of them.

I do not, however, tie one to each seacock, which would be a bit ridiculous since I have 18 or 19 through hulls in my boat. I keep them under the companionway stairs. You can block a broken through hull with your hand while someone brings the plug. Or once you've located the broken through hull, your boat will not likely sink in the 15 seconds or so it takes you to get to the bag of plugs.

Yikes 19 through hulls. Why don't you get rid about 15 of them and just put manifolds to 4 of them with 3 to 6 lines hooked to each manifold with their own seacocks. I don't think the Titanic had that many through hulls. I'm surprised your boat is still afloat <sarcasam> I've got one and I'm still thinking of a way to do away with it.

[Cheechako]

Originally Posted by Dockhead

Gas pump is nice for being completely independent of any other power supply.

However, they have two huge disadvantages:

1. You can't store them inside the hull volume due to fuel vapor risks, so where will you store it?

2. Small gas engines are notorious for not starting if they don't have fresh fuel, are not used regularly, carb drained between uses, etc., etc. Are you going to have time to deal with all of that, for an item of gear you will (you certainly hope) never use in anger?

I'd much rather rely on an engine I'll be using anyway for many other purposes, either main engine (pulley driven Jabsco with magnetic clutch) or generator (230v electric trash pump, my own choice).

Yes I agree, the use of an independent powered engine would have it's difficulties for sure. Fine if flat water, but with Murphy around, you wont have a leak in flat water! However my point was the average engine impellor pump is useless. If you want to mount a trash pump with clutch on your engine that might be useful!

[Kokanee]

It's worth doing a test by pulling off the raw water inlet hose to your engine to see if your bilge pump can keep up with the inflow. I see that as a minimum rate your pump should be able to handle.

Also - the weak point of any bilge pump is often the float switch. A failed float switch caused me some grief when the exhaust hose slipped off the water muffler and filled the bilge while motoring. Luckily, I had a manual run switch for the bilge pump, so it only resulted in a shorted out starter motor. ( btw - If you submerge your starter motor, dry it out before use)

Now I have a second bilge pump and float switch with alarm. (and a new starter motor)

[Mr B]

I have a Cat,
other than the thru hulls which are under inspection plates in the floor, and can be inspected easily,
Any hole in my boat would be impossible to find,
My boat is two moulds that join at the top of the Hulls, So I have a false floor, and its sealed, So other than knowing which hull has a hole in it, Its got water in it,

I would need to keep pumping till I got onto a beach so I could find the hole by walking around the out side of it,

Looks like a decent capable pump running of the main motor is the go,
My Bilge pumps wouldnt go close to handling a hole in the boat,

[Dockhead]

Originally Posted by Rorzech

Yikes 19 through hulls. Why don't you get rid about 15 of them and just put manifolds to 4 of them with 3 to 6 lines hooked to each manifold with their own seacocks. I don't think the Titanic had that many through hulls. I'm surprised your boat is still afloat <sarcasam> I've got one and I'm still thinking of a way to do away with it.

I agree -- I don't like it.

My next boat will have a sea chest and standpipes, which will all be located behind watertight bulkheads out of the main passenger volume.

[Dockhead]

Originally Posted by Cheechako

. . . However my point was the average engine impellor pump is useless. If you want to mount a trash pump with clutch on your engine that might be useful!

I completely agree with this.

Bilge pumps are not really designed to dewater a boat in a flooding emergency. They are designed to get rid of maintenance volumes of water in the bilge.

A pump which will be really useful in a real flooding emergency should move enough volume in realistic conditions (not the nominal capacity based on zero head, zero hose friction) to keep up with a significant hole in the boat. Also, it should be capable of dealing with trash in the bilge water. It needs to be a very large capacity trash pump of some kind or another, in my opinion.


By the way, I like the Predator bilge pumps made in England. These will deal with large solids and really look the business -- not just a "bilge pump". I will have these on my next boat.

[tkeithlu]

Stay Afloat remains controversial, due to doubts regarding its ability to withstand water under real-life conditions - depth of water outside the leak, size of hole, hitting waves, and the like. Also controversial is using the coolant pump as an emergency bilge pump. I'm not sure of all the arguments there, but any obstruction to flow or even success, such that you suck air, would burn out an impeller pump very quickly.

A motivation of mine in building my boat was the large number of seacocks that were in hard to reach locations in trawlers on the market. I consolidated them into one very large seacock with a strainer, and remounted the lever so that up is off. That let me run a wire to the main salon above the engine room. Pulling the wire cuts off all water to the boat with out my having to enter the engine room. It means long hose runs, which I guess manufacturers try to avoid.