Has anyone tried one of these? They are less than half the price of a Rule 500 automatic.
Seaflo Automatic Submersible Boat Bilge Water Pump 12v 750gph Auto with Float Switch
http://www.amazon.com/Seaflo-Automatic-Submersible-750gph-Switch-new/dp/B00B0L4ONM/ref=pd_sim_sg_3?ie=UTF8&refRID=02QS6HKHKZ09FZAQHJ08
Nice price. WW canoeists experiment
with bilge pumps, with hand switches. Battery packaging is still an issue. I didn’t read far enough to see how shallow the water can be and still trigger the pump.
If you want an auto pump
You might want to look at this one. http://www.whalepumps.com/marine/product.aspx?Category_ID=10008&Product_ID=10002&FriendlyID=Supersub-Smart-Family
I believe these are made in England but I found them online in the states. Instead of some kind of float it has an electronic sensor. I considered it but it was too long for my latest bilge pump setup in my Valley Avocet RM.I use a manual switch, a magnetic reed switch. Fully sealed in glass tube, tube then gets incased in epoxy. I did my latest bilge pump same as I did my first one on my NDK. Link to NDK install with video link to youtube here. My battery only weighs in at 12 ounces and can easily pump out kayak well over a dozen times. I seen some others use lead acid battery but that’s crazy OLD TECH now a days. http://www.pbase.com/dc9mm/kayak_bilge_pump
automatic pumps
At least among whitewater boaters, automatic electric bilge pumps have been generally rejected, although I admit I have never tried one. I am told that a relatively small amount of water, too little to be effectively pumped out, tends to keep activating the pump as the water gets sloshed around in the boat.
The favorite manual electric bilge pump seems to be the Atwood Tsunami rated at 1200 gph which can be had for about $30. Sealed lead-acid batteries are heavy relative to other types, but they are rugged, much less expensive, and can be used without any waterproof case.
A waterproof switch like this one will work fine, at least in fresh water:
http://www.weisd.com/ProductView.php?PN=NTE54-354W
Some whitewater boaters use very inexpensive switches and simply seal them up with silicone caulk.
No float switch
You are better off with a magnetic reed switch, an Orca whale pump.
pick a reed switch/ pump combo so that the current draw through the switch doesn’t require an additional relay.
I’ve built one and few other friends have. I used a 14v LiPo battery pack and small pelican box with a feedthrough going through the rear bulkhead, pelican box mounted to bulkhead with velcro. A magnet mounted in a chunk of plastic sliding on deck line triggers reed switch which is glued and to underside of deck. Cost about 80 total.
Or spend $500 and buy the same thing from Bluewater kayak.