Re: [Amel Yacht Owners] Bilge / Sump pump
Bill Kinney <greatketch@...>
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Using a submersible for routine service in the Amel bilge would NOT be a good idea. What we call our “bilge" really is not a bilge in the traditional sense of the word. It is actually a grey water sump. Submersible centrifugal pumps would foul and fail in very short order. Submersible pumps can also cause all kinds of stray current problems that you really don’t want to deal with the consequences of. This would be one of those changes from the original Amel design you should just say “No” to.
It is very hard to find a 24 volt pump that is as suited to this service as the original that Amel selected. If you can find one it would be best. Really.
But if you can’t, there are good options...
There are only a few kinds of pumps available that will work as a grey water discharge pump on an Amel. Diaphragm pumps (like the original); some kinds of piston pumps; and possibly some flexible impeller pumps.
I worry that a flexible impeller pump would have trouble with the self-priming at the depth of the well, so I hesitate to recommend them.
Diaphragm pumps are good at pumping “dirty water”, but you need one that is very well designed to work for very long. Most mass-market marine pumps of this sort are designed for very infrequent service as shower sump pumps, and they are even short lived at that. Amel's pump is first-rate and has a long lasting diaphragm and check valves. There are others, like the line of pumps made by Bosworth that that seem very well made, but I have no experience with, and can’t comment on longevity.
One pump that would work well in this service is the T-series discharge pump by Sealand. They are robust, long lived, easy to care for, excellent at self-priming, no foot valve would be needed. This is a piston type pump, without the rubber diaphragm. Maintenance consists of changing check valves about every 6 months. These are made as raw sewage pumps. If a “chunk” can fit up the hose, they will pump it through. They can handle the “gunk”. BUT… the downside is they have lower capacity than the Amel original, and so will run longer on each discharge cycle.
Sealand also makes an “M” series pump of the same design, except with a bronze body that is much larger and has at least the capacity of the Amel original. Check hose sizes and space for this one to see if it is practical replacement.
I don’t have any interest in Sealand pumps, other than using one daily as a pump for un-macerated raw sewage for ten years with only routine maintenance. It just worked.
I have the good fortune that my boat came with a complete working spare of the original pump. Hopefully I can keep the original running for a long time yet.