I tried a hose + strainer too and that didn't dry the bilge either. The only electrical
thingy that succeeded with my tests was a shop vac.
With the PVC pipe, I use the standard PVC clamps to fasten that size of pipe. At the top of the pipe, I use PVC cement and an elbow
to create a 90 degree turn, followed by a couple of inches of pipe again and a pipe-to-thread fitting. Then, I mount a clamp on the vertical part so that I can still adjust the height of it. Then I test, bringing the pipe down while pumping to decide between the volume pumped and the amount of water left later. I only have a couple of mm left, which quickly evaporates.
: a float switch will switch off long before the pump finished. You can use nice & spiff vacuum switches to keep the pump running as long as it's not drawing air, but the Gulper can pump air+water mixture too, so you will stop too soon that way. I am now using a solenoid with timer (from Raritan
toilet) and adjust the timer until it's just perfect. I mount the float switch to the bottom-end of the draw-pipe itself using a little bracket made of King Starboard.
For my gray water tank, this system is foolproof. Every 6 months (we're talking full time use for _all_ gray water aboard) I need to rinse the (cheap, standard) float switch to get it unstuck. The incoming gray water drops on top of the float switch for self-cleaning action. This too was found to work the best after many experiments.
Every 3 years I need to replace the float switch because the float fails (fills with water). The pump didn't need any service
for the past 5 years.
Compared to the old "traditional system": it needed maintenance
every 3 weeks which included removing and disassembling it's $100 super float switch, cleaning
the yucky soap residue out and disassembling the macerator pump to clean the shaft from hair wrapped around it. It needed a new pump-head every year or so.
Also, the hose & strainer needed cleaning
while I never had to touch the PVC pipe again.