If you boat is not in the water, you can take a piece of cotton wick material, place it in the bilge, run it out the garboard drain and leave a foot or so hanging out. Make sure it's in the lowest spot and your bilge will be bone dry. Kind of a pia during the season, but it is worth it. I wrap the wick on stainless nut on the forward end so it stays put, and leave a carbon arrow shaft in the bulge to manipulate it out the drain hole.
Only works on bracket boats long term obviously, but if you have standing water, it will start dripping almost immediately and have it dry in a day. No moving parts, and you can get the wick material off Amazon for 50 cent per mile. A strip of T-shirt works just as well but a lot harder to get through the drain. You don't want to restrict the capillary action.