so, we've all learned that you aren't supposed to use a check valve with a
bilge pump. it's in all the instructions for
rule bilge pumps. its in articles on-line. it's in the FAQ section on
rule bilge pumps.
if you use one the
pump may fail to operate due to a few different issues.
airlock conditions may form.
the check valve may get stuck open.
the check valve may get stuck shut.
the
water on the other side of the valve may be too heavy for the
pump to push open once the flow is interrupted.
just
google 'why can't i use a check valve with my bilge pump' and you'll see all the reasons written out. the long and the short: if you use a check valve, your
boat may sink.
now, i have a 1971
cal 27 pop top that i am refitting. when i bought it the first thing i had to do was install a
bilge pump; marina's orders. i did so per the rules. i always do things the right way. no shortcuts or half-assed fixes. i'm like ford: quality is job one.(that is ford, right?)
it worked fine. as we all know, there is always a little
water in the hose that comes back when the pump stops pumping. no big deal. never enough to make the pump come back on.
two years later.
a lady who lives aboard a
cal 2-27 asked me to install a bilge pump for her. she has never had one. her
boat recently started leaking around a through
hull and gave her quite a scare. they got it patched temporarily and used an AC powered bilge pump to empty the bilge.
the marina manager recommended she get a rule 800, which she did before she asked me to install the pump. i told her it was too small and she should have gotten an 1100 like mine but, i installed it. i wired it to a switch so she had off/manual/auto functions.
her bilge is different than mine, although her boat has a similar
draft (lapworth designed a completely different boat for each of the 3 cal 27s). my bilge is the same
depth back to front. so, my pump sits in the middle of a space that is as wide as hers but as long as my entire fin
keel.
her bilge has a step. the forward 1/2 (or more) is pretty shallow and the final part is deep. this means that, while the space her pump sits on is no narrower than the one in my boat, it's quite short.
she first wanted me to
route her hose to the transom to use the through
hull that her whale manual pump used (no extra holes in the boat). i never thought this would
work. her freeboard is a good bit higher than mine; meaning it's a lot farther to get up out of that bilge to free air.
as i thought, the pump just kept running. it emptied the bilge but, kept pumping out the last hose full over and over.
it had to be a shorter run! but, she didn't want any more holes in the hull. what to do? well, i had an idea. i could put a through hull in the
cockpit bench, right near the top of the bridge
deck. she will never take the boat out of the bay and, if it became a concern in bad
weather, she could always turn off the pump and
plug the through hull. the scuppers could certainly handle the water from the bilge. shortest run possible. but, i didn't have a through hull so i'd have to do it the next day. (she also had me take out the 800 and put an 1100 in)
unbeknownst to me (because she never told me) she took the pump out of the deep bilge, after i left, and put it in the shallow bilge.
so, i install the through hull fitting and cut the hose, fitting it to the through hull properly, so i thought. after it's done, i say about testing the pump and she says we'll have to put it back in the lower bilge!
there was just enough hose....barely.
we put water in the bilge. it works but the pump has to cycle 4 to 5 times before the returning water doesn't turn the pump back on. even with the absolute shortest run, it's almost too much water. even though the run in mine is now longer, the fact that the space her pump occupies is so small means the little water rushing back in gets too deep.
but, it works fine. i explain the situation. the fact that it will, ultimately, stop cycling. it just takes a bit. i figure all is fine.
during the night she decides to see if it does
work properly and dumps water in it. since it doesn't stop cycling immediately, she takes it back out of the bilge!
she talks to the marina manager again and he suggests a check valve. she goes out and buys one along with more hose so i can rerun the hose, since she caused it to get cut short... i haven't seen it yet. hope she got a joker valve and not a spring operated valve.
[note about the hose: she hasn't considered that it's not necessary to rerun the entire hose since i have to unhook the hose from the pump, fit on the check valve, and add a piece of hose so i can reconnect to the pump.i hope she didn't rip it out! it was a pain to
fish in.]
i tried to tell her, before, that you were not supposed to use a check valve on these. that it can cause pump failure. even showed her the place in the instructions where it says that (with a magnifying glass! who do they write those things for? ant man?)
anyhow, she's adamant about it. the marina manager (who recommended the too small pump) said that's what you do. i told her i would talk to the guys at rule and see what they say.
so....what did they say?
he said to put in a check valve!?!
yeah. read that one again.
after all the hoopla. the warnings in the instructions, the FAQs, all the other stuff on-line about not using a check valve or your boat will sink. he says use a check valve. (a joker valve and not a spring operated one.)
i was like, " but, what about warnings in the instructions, the FAQs, all the other stuff on-line about not using a check valve or your boat will sink?"
he tells me, that's why he asked if the hose outlet was at the waterline. some people (sheer idiots, i suppose) think that putting a check valve at the outlet of a hose that dumps near the waterline is sufficiently safe to keep water from coming back in. that's what you don't install a check valve to do: hold out the ocean. but, he says, the proper reason to install one, down near the pump, is to deal with backflow from water stuck in the hose.
i am just blown away. if that is the case, why not say so on the instructions and FAQs and all the other stuff on-line about check valves and bilge pumps?
(ha! got you. bait and switch. you probably thought i was going to finish with "...about not using a check valve or your boat will sink". crafty little bugger, aren't i?)
that just blows me away. really. i'm no longer, here, typing this. i'm bouncing along down the street, on the
wind.
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