Backup or Secondary Bilge Pumps - High Water Alarm Water-Sloshing in Bilge

Speaking of bucket list items while we are hauled out, the subject of a high water alarm for the bilge has come up several times as we have reviewed, repaired and upgraded our boat systems.

Any comments from the IPYOA family on high water alarms as a retrofit, and/or the installation of s second (backup) electric bilge pump? With regards to a second pump, seems to me a new circuit would be required? Where would the 2nd bilge pump switch be positioned in comparison to the primary pump switch.

Finally, there are a number of older posts recommending placement of the primary bilge pump switch higher than the (bilge) water line to reduce intermittent pump switching when water sloshes around. Has this proven to be an effective solution over time?

Thanks in advance for the input.

The attached pictures depict the easiest possible high water alarm solution. Andromeda has one of these 9v alarms for the bilge and one for the engine room as well as a hard wired 12v alarm for the bilge.
George Henry
S/V Andromeda, IP44-35,
Isla Mujeres, Mexico

Finally, there are a number of older posts recommending placement of the primary bilge pump switch higher than the (bilge) water line to reduce intermittent pump switching when water sloshes around. Has this proven to be an effective solution over time?


Did you ever receive any answers to this? Having just completed our first passage of four days from Langkawi to Singapore, I was stunned at how oftent he automotiic bilge pump engaged. I think it is mostly a result of "drain back" of water that didn't make it over/out board and flows back into the bilge. A check valve is an option but I'm thinking the better approach would be to adjust the water height of the float swtich...

Unfortunately, no one else has chimed in on this issue.
We did install a bilge alarm, and with that respositioned the bilge pump switch. We just splashed and will be out during the week to get a sense for the result.