Planning on plumbing 3 Jabsco pumps. Using 1" tubing. What size thru-hull without restricting flow?!

i think the size of the fitting is the same as the tubing they fit. the hole saw you end up using will prob be 1 1/4" to 1 1/2" depending on the fitting. I ordered mine from West Marine and thats how it worked.

I am not a fluids expert... <BR> <BR>My sense is the wider the better with diminishing returns. <BR> <BR>The Jabsco pumps connect 1" OD and 1/2" ID. <BR> <BR>area of 3 pumps = area of one circle <BR> <BR>3 * pi * 1/4**2 = pi * r**2 <BR> <BR>r = 0.433"; d = 0.866" (diameter). <BR> <BR>Thus, 1" or 1.25" hull hole should do it. <BR>Anything larger that 1.25" is probably overkill.