[C320-list] Bilge Pump Makers? Comments? Experiences?

[Stephen Cox]

On 2 July 2017 2:20:49 AM AEST, Danny Jensen <danny at jensenshouse.com> wrote:
>Steven,
>I'm interested in using a relay connection to run my primary pump off
>my alarm float switch per your design. Where did you get your relay?
>
>Good idea about having a hot spare auto sensing pump. Do you have the
>part number for the primary Johnson pump?
>
>Sent from my iPhone
>
>> On Jun 30, 2017, at 6:17 PM, Stephen Cox <scox at timmin.com> wrote:
>> 
>> My MkII came with it's bilge pump fitted in the bilge itself.  It
>ultimately
>> failed with a small wood chip from the build process jamming the
>impellor.
>> I subsequently installed a much larger Johnston pump.  
>> 
>> However, there was enough water collected in the bilge at one stage
>to
>> trigger the pumping process but not enough to really pump the bilge
>right
>> out. So with the back flow of what's left in the delivery tube the
>setup got
>> into a start stop repeat cycle.  Inevitably before I could fine tune
>the
>> shaft packing gland correctly, this repeat cycle happened while I was
>away
>> for some weeks.  The nett result was that the bearings in that
>Johnston pump
>> suffered somewhat from being continually run in a partially dry
>environment
>> and are now very noisy.  
>> 
>> I don't believe putting a check valve in is the answer as the ones
>supplied
>> with most pumps I have seen are just rubber flaps that will not seal
>> effectively over the longer term. At best they would just slow the
>cycling
>> process down, not eliminate it.  Any more substantial "proper" check
>valve
>> will impede the flow of water obtainable because of the pressure
>needed to
>> overcome the valve mechanism, hardly a desirable outcome if taking on
>> serious water.
>> 
>> I have now fitted a pump to the front bilge compartment of the same
>size as
>> that originally fitted but with automatic sensing involving the pump
>> spinning up briefly every little while and sensing the load.  If
>there is a
>> load it continues spinning until all the water has gone and the load
>> decreases.  Yes there is still a back flow but it is smaller.  It is
>still
>> possible to get just the right amount of water in the bilge to cause
>a cycle
>> pattern to occur but because of the sensing process this is at least
>> periodic rather than continuous.
>> 
>> I have also replaced the larger Johnston pump with a new one, fitted
>in the
>> rear bilge compartment, with a separate larger disposal hose to the
>rear of
>> the boat. This new one is set up with two float sensors and some
>latching
>> relays to cause a significant water level differential between pump
>on and
>> pump off.  So no cycling occurs unless there is a real need. i.e.
>continuous
>> ingress of water.  The sensors are set to only fire when the water
>level is
>> well above the trigger point for the smaller pump, so it is an
>emergency
>> rather than a day to day bilge pump.  An alarm also sounds when this
>pump
>> runs.  Both pumps are independently fused.  I have the disposal hose
>outlet
>> to the side of the rear step, spraying out over the ladder lid, to
>easily
>> see if it is pumping and how solidly.
>> 
>> Further refinements have been:
>> 
>> 1. Purchase a second identical automatic sensing pump as a spare and
>I have
>> also kept the noisy larger pump as a spare..
>> 2. Fit waterproof plugs and sockets to both pumps' electrical leads
>and
>> screw connections on the hoses.  This means if I have a pump problem
>at sea
>> I can quickly replace the pump.  Trying to make jury rig electrical
>> connections or get hose clips and hoses apart in a heavy sea is not a
>> realistic proposition in my opinion.
>> 3. I have fitted a completely separate water level sensor at a fairly
>high
>> level to catch the situation when both pumps for whatever reason
>don't
>> appear to have worked.  This sensor drives another bilge alarm and
>two
>> independently fused relays connected to the two bilge pumps.  This
>covers
>> the situation where the normal sensors have failed and serious water
>is
>> coming in and will ensure that if one pump has also failed at least
>the
>> other one will be kicked off.
>> 
>> This all sounds a bit belts and braces but does bring peace of mind,
>> particularly if sailing single handed or with inexperienced
>passengers
>> rather than crew.
>> 
>> I don't think we will ever solve the cycling problem without being OK
>about
>> having some water in the bilges.  I try to keep mine dry as an easy
>way of
>> checking for water ingress.
>> 
>> 
>> 
>> Stephen Cox   
>> Tegwen #1141
>> 

I'll get back to you later in the week. I am away at the moment.

Stephen Cox

Tegwen #1141