Hand Bilge Pump
Putting the water back where it belongs
We are just about over the summer sailing season as I write,
and for the many of us who dont get out so much over the winter
there is an opportunity to rectify a whole seasons worth of
neglect and abuse of the boats systems.
There may be a little water in the bilge sump, perhaps condensation
and a little spray that came aboard through a hatch left slightly
open to let some air in. The missing three of spades and a
pair of underpants (the activities were NOT connected) have
joined the half roll of paper towels that went down the gap
at the back of the locker, a whole seasons odds and ends have
also ended up in the lowest part of the boat and the whole
lot has been sloshed about by a seasons active sailing becoming
a noisome sludge that is indigestible by even the most voracious
of bilge pumps.
Along comes our hero, the boat is motored over to the haulout
with the foul brew lurking under the floorboards making the
boat not the nicest of places to be with the hatches shut
so our hero forsakes his normal place, posed behind the helm
(heroically of course) and heeding his wife’s threats
never to go sailing again if the boat smells like that he
ventures below to pump the mess out. You must be kidding!!!
Just as well it wasn’t a leak that prompted the attempt
to use what is, after all, an emergency device.!
A diaphram pump such as we use is very similar through a wide
range of brands, Jabsco, Edison, Vetus and Whale are among
the best known but most of them share the basic principals
and differ very little one from another and all bar a very
few can be stripped fairly easily for service.
Self priming in an installation where the pump is no more
than a couple of metres above the inlet , able to move a lot
of water in a hurry, ( although there is a saying that the
most effective bilge pump of all is a frightened sailor with
a bucket) and generally capable of pumping water contaminated
with a fair amount of rubbish the diaphram bilge pump is a
wonderful device eminently suited to our sport. However the
awful slurry that accumulates in some boats, or the mess that
is floated by an incoming rush of water from a damaged skin
fitting or engine cooling system will choke even the largest
mouthed of the type.
Oddly enough the boat with “dusty bilges” is
not without risk of bilge pump failure, like anything that
does not get used for long periods , when desperately needed
it may have become so unaccustomed to work that it may not.
Don’t skip the servicing and do check the function with
a bucket of water a couple of times a season.
Also a problem in a dry boat is the steady accumulation
of tiny odds and ends under the cabin sole. From normal dust
and fluff to the occasional (unlit I hope) match dropped when
rolling in a seaway these little bits are without peer when
it comes to preventing the function of the valves inside the
desperately needed pump trying to keep a previously always
dry boat afloat. The dry boat, while the most desirable kind,
has problems of her own. Make a tidy up down there in the
bilges part of the normal housekeeping in any kind of boat.
One hopes never to need the services of your bilge pump,
but like other (more expensive) forms of insurance it had
better work if you need it. Being a bit “out of sight
out of mind “ it pays to check the installation out
now and again before Murphy’s Law strikes and you need
it with a vengeance.
Note that I said to check the installation out. By that
I mean that the pump does not work in splendid isolation,
you need to look over the entire system not just the pump.
Start with the pickup end of the inlet hose, if allowed to
pick up some of that mess I have been on about you wont be
pumping, you’ll be swimming.
A “ strum box” is the way to protect the pump
from clogging and to be effective it needs to be a big one.
Rather like a mesh cage, or a box well perforated with holes
, small enough ones to stop anything that might clog the pump,
and numerous enough to pass the pumps rated capacity in water
even when partly clogged itself. One of my more knowledgeable
contacts recommends a surface area in the strum box of at
least 20 times the cross section of the inlet hose. Yes, it
Next link in the system is the pickup hose itself, as a
suction line this is a vital piece of equipment. Suction will
tend to collapse the hose if weak or bent around a tight turn,
and any leaks in hose or end fittings will admit air that
could render the pump ineffective.
Check the hose for condition and re-route it if necessary
to take the kinks out, replace the fittings if they show even
the slightest sign of deterioration. Make sure you use stainless
steel hose clips or fittings or you will be having to renew
them next season, and the one after.
Diaphragm pumps are very simple, there is a pump chamber
with one, or two valves to control the water in and out, the
chamber has one side made of a flexible material which is
moved in and out by the lever on which the operator swings.
This makes the chamber larger then smaller, sucking water
in through one valve , then forcing it out through the other
valve and so overboard. these valves are , together with the
diaphragm itself, critical to the operation of the pump. Normally
a simple flap they should be very flexible, without any cracking
or damage to the seating or valve material, any cupping or
curling will prevent the valve from sealing properly so if
any of these problems are evident it is a replacement job.
A major wear point of any pump is the diaphragm itself,
continually flexed in and out it can eventually crack or split,
a few might perish over time so all require careful inspection
at regular intervals.
Around the edges the seal between the body of the pump and
the diaphragm should be perfect . While the edge seal can
be helped with appropriate sealing compound if a persistent
leak is evident this is not the ideal repair. Some are gasketed,
some are secured by screws and some have a plastic ring that
may bulge if over tightened and suck air rather than water.
In fact when using metal screw or bolts in plastic components
it pays not to do them up too tight in any case. I do use
a smear of Anhydrous Lanolin ( wool grease without the smell)
on my pump parts but do check that it is compatible with the
synthetic rubbers used.
Some of the better pumps have a “door” in the
front to allow rapid access and clearance of the valves if
blocked so check the gasket and the closing mechanism. If
retained by a screw threaded nut or bolt make sure this is
free and not immoveable with corrosion. While at it check
the interaction of the various metals within the pump, dissimilar
metals can suffer from electrolytic corrosion and I have seen
alloy bodied pumps bolted down with brass bolts, a sure recipe
Mechanically speaking there are very few parts to worry
about, two or three pivot pins, all of which should be positively
retained ( check the split rings or securing split pins, never
use split pins twice.) and not sloppy in their bearings, the
handles stowage is also an important part of the pumps functionality
so make sure it is going to be “right there “
even after a full rollover.
Mounting the pump correctly is vital., the mounting has
to be strong enough to cope with a panicky pumper , the bolts
need to be big, well washered, fitted with locknuts and very
strong. The pump has to be positioned so that pumping is easy
and can be sustained for a long time and last but not least
every part of the system needs to be easy to get at to unblock
Finally, the outlet hose. As this is under pressure it can
be a little “sad” and still function but while
you are in overhaul mode why not check it for routing, fittings,
condition and length. Look hard at the through hull fitting
too, you might end up energetically pumping the water back
into the boat!
Water and boats have a love hate relationship, Love the
stuff outside, hate it inside. Your bilge pump is an essential
part of keeping this relationship a livable one so look after
that so often neglected pump and never forget that it is part
of a system, very simple sure but still, all parts of it have
Who knows from experience how fast a frightened man with
a bucket can move water.