Bilge pumps are great to have...
but do no more than hide the symptom of a different problem until your float switch or batteries fail. You really need to address the stuffing box issue where presumably most of the bilge water is coming from. As David said, the job of fixing it is intimidating but not all that difficult to do. Here is the link he posted which is very informative if you read the whole thing: http://www.pbase.com/mainecruising/stuffing_box&page=1I installed one of the electronic bilge pump switches on our Tartan 27' when we had a bad stuffing box leak going on from the need of re-packing. The automatic switch and pump lulled me into complacency and one time we got to the boat after an extended absence and there was 6" of bilge water above the cabin floor (sole). Not good, not good at all; we needed a new battery, to change our inboard engine oil 3X to get the water out of it, to dry and clean everything that was below water. Do you know when your stuffing box was last re-packed? It is said to be about a 5 to10 year maintenance issue depending on accumulated engine hours. Since then I have re-packed my stuffing box and removed the automatic switch completely and try to make sure that weekly visits are made to the boat. No problems and no big leaks. If you have a keel stepped mast you might want to ensure that rainwater does not also get a free ride to your bilge from that and find out if other thru deck fittings might be leaking water.Cost of complacency: well over $100 (new marine deep cycle battery $$$, 3 gals of engine oil plus the time to do.Cost of fixing stuffing box (if you already have the wrenches): about $16 + shipping for the packing material if you know the right size to get: http://www.emarineinc.com/products/gfopacking/packing.htmlThe first thing you should try though is to try and tighten the packing nut on the stuffing gland a bit to see if you can stem the flow somewhat. I would spray these bolts with PB Blaster or at least WD 40 a day or two in advance and then see if the wrenches enable you to get them to budge. Start with the packing nut which is farthur down the shaft and see if you can get it to tighten. If the flow diminishes then tighten the locking nut down on the packing nut. Read the link I posted and David recommended.Good luck and sleep soundly.