Limber holes

[Adamastor]

You could fit multiple bilge alarms on a simple mimic panel and have the pumps discharge to a single overside fitting near, say, the sheer. As long as the upstream pipe and fittings are greater than the sum of the pumps' outlets you're not at any risk: 2 × 3/4" pumps can discharge together into a 1" pipe and outlet quite happily. As for pumps, you would be best served by diaphragm pumps if you want to have dry bilges, because, let's face it, centrifugal pumps are only good for flattening the battery if there's a real popular uprising and the sea is really intent on coming aboard!
The chain idea in the limber holes is really olde schoole, so it works like ye olde magick, and nowadays a length of knotted modern rope would probably do the trick. I've seen a strip of orange-bag used for a similar purpose to free baffles in a slush-hold on a fishing boat!

 

[Seajet]

I have no skin fittings on my boat - the loo is chemical ( which can be used on the drying mooring ) abd the sink pumps out waste via a bilge pump into the outboard well - that pump has a diverter valve and roving hose so I can pump the bilges from below if quivering shut down.

I fitted seacocks on the pump outlets in the well - they are above normal waterline but maybe not if a compartment aft is compromised and trimming the boat down by the stern so one needs control of such things.

An important thing to mention;

on any sail a decent skipper will brief the crew as to the

lifejackets,

Harness lines & clip on points

VHF

Switch Panel

Flares & how to use them

Bilge pumps

Gas valve & methods ( ie shut off unless in actual use )

First Aid kit

Nav system / at least latest position

Fire extinguishers

Inflatable dinghy stowage & hi speed pump procedure

At least rough MOB - in case I'm the one who goes in -

Engine fit & startup, handling.
------------

A good briefing - kept casual - is not only an essential safety aid, it should not be intimidating but enough to put the minds at ease of less experienced people - there's nothing more unsettling than feeling one is in a vehicle one cannot control, hence a lot of peoples' fear of flying.

 

[Len Ingalls]

And if possible, above the waterline when she is lying over on the beach and the tide comes back in, which would be when you want cocks on the bilge pump outlets to avoid the sea coming in where it's meant to go out!

I agree. If I careened regularly, I would want ball valves in each above W/L thru hull.
I'm not sure I would trust check valves in B/P lines. A bit of culch floating in bilge could possibly jam the flapper.
Another problem at my location is freezing. A check valve will prevent the water in the hose from draining back thru the pump & into the bilge when pump shuts off. That water in hose can freeze & split hose,etc. It does happen.
All boats & situations are not the same & you must act according to your situation.
Cheers/ Len

 

[Seajet]

I agree. If I careened regularly, I would want ball valves in each above W/L thru hull.
I'm not sure I would trust check valves in B/P lines. A bit of culch floating in bilge could possibly jam the flapper.
Another problem at my location is freezing. A check valve will prevent the water in the hose from draining back thru the pump & into the bilge when pump shuts off. That water in hose can freeze & split hose,etc. It does happen.
All boats & situations are not the same & you must act according to your situation.
Cheers/ Len

Good points; as it seems the Royal Navy are having to re-learn about the troubles of temperature extremes hot or cold, freely available advice which RN or more likey in my experience trying to work for them, BAe customarilly ignored.

 

[sarabande]

one disadvantage of a manifold (one pump drawing from selected bilges) is that if the manifold or one of the valves leaks, then you will recycle bilge water back into the boat.

 

[grumpy_o_g]

Have anyone been able to find a bilge pump that can remove all water?
Having many small compartments with 5 mm or more water left don't sound tempting.
Imagine opening up each one to sponge out the rest...

Whale super sub are pretty good at getting down to the dregs but may not be man enough for a main bilge pump. Common to use them in conjunction with a bigger pump

http://www.whalepumps.com/marine/pr...uct_ID=10002&FriendlyID=Supersub-Smart-Family

 

[Len Ingalls]

one disadvantage of a manifold (one pump drawing from selected bilges) is that if the manifold or one of the valves leaks, then you will recycle bilge water back into the boat.

+1 Use a separate above WL outlet for each pump is safest IMHO

 

[Len Ingalls]

Have anyone been able to find a bilge pump that can remove all water?
Having many small compartments with 5 mm or more water left don't sound tempting.
Imagine opening up each one to sponge out the rest...

A wet/dry shopvac or a sponge is all I've found / Len

 

[Gordonmc]

As suggested, a length of chain or rope running the length of the bilges is sometimes the only way to keep limber holes clear.
In my previous boat, a Hillyard, the bilges were full of trimable balast and getting down to the holes meant lifting numerous bits of pig iron.
I used nylon rope with knots ties at suitable intervals in such a way the knots were normally half-way between the bearers.
Every so often I just pulled the knots through to clear debris, then back again.
The idea that I could ever have dry bilges is somewhat whimsical.

 

[pmagowan]

Unfortunately my limber holes are too small for that solution as any obstruction would simply cause them to blovk more often. I think i will have to enlarge them.

 

[bedouin]

I was thinking it might be needed to avoid down flooding in the event of beaching, with the boat lying on her side. It happenned to me recrntly and I had to climb out and bung the outside of the bilge pump outlet, to ensure the sea didn't enter when the tide came back in.

My electric pump outlet is just below the toerail - so is well clear of the water even when refloating after beaching It is also easily accessible from deck so in case of emergency it would be easy to bash a softwood plug in - much easier in fact than trying to get the a seacock on the inside of the hull.

I simply can't imagine any circumstances in which I would want to close a seacock if I had one

 

[Seajet]

All my bilge pump outlets are 18" or so above the waterline, in the outboard well - happily my boat has no underwater skin fittings - however I fitted seaocks in case some damage led to a big stern down trim.

May sound unlikely especially with the separate compartments I fitted there but an acquaintance managed to collide with a steel fishing boat and nearly have the stern taken off, entering Yarmouth in a sinking condition...

 

[RupertW]

Our limber holes are about an inch in diameter and haven't blocked yet, though in a previous boat there was a length of string going through them for pulling about and clearing any minor blockage.

Alas ours are used all the time which is frustrating and I haven't been able to pin it down, though current theories are our middle water tank (the inlet was glued shut when we bought the boat) and the fridge drain which I haven't been able to access and may have originally (or still?) been attached to an incomprensible diverter valve and seacock arrangement under the sink.

Plus the propellor shaft drips a little sea water into a walled off section under the engine but that goes nowhere just means I had to scrape out salt a few inches deep from it, but that could have accumulated over many years.