Outlet port for that bilge pump

-- Last Updated: Jul-13-11 12:04 AM EST --

yiminy! by this time you are thinking you should just come over to my shop and install this thing yourself, right?

Installed a few more pieces and my next question is where to put the outlet port. I will be using a 90 degree, through hull fitting. I don't like the fact that the fitting works on hulls up to an inch and a half thick, because in my installation the down turned sleeve is a couple inches off the inner hull surface. But, as JV says, they don't always make the parts we need. That is besides the question of where to position the outlet.

Previous writers have suggested the outlet tube should be kept as short as possible. My pumps are behind the saddle, and the shortest possible route for the tube is to go straight to the nearest high point on the hull, which in this case, is just aft of the saddle. However, this is also the spot the hull that has the least freeboard, and it seems like the higher the better. Higher means positioning the outlets further aft, where the hull gets taller.

So, shortest tubing route, even though it is also the lowest point of the sidewalls? One advantage of the perpendicular route is it interferes less with the airbags. Is that where to place the outlets? Scares me drilling a 1.25" hole in the hull. I'd prefer to get it right.


shortest route
Not sure I follow your thinking about the lowest/highest point of the boat. What difference does that make? Shortest route is best in my opinion. Less head for the pump to push. I’ve seen systems where the outlet just goes over the top of the gunwale. One outlet on each side seems to move a substantially greater volume of water than a single outlet.

why drill right away?
I’d just run the hose over the gunnel and secure it down for a while. Then you can see what the tradeoffs are before the “big commitment.” All the ones I’ve installed just sit on top of the gunnel. I haven’t drilled any yet. I thought about it. But I stopped short when all they had at West Marine was the 1.5" thick ones like you described.

I do know that shorter hose is better. And I doubt you’d have any trouble running the penetration through the low part of the hull. But how low would it have to be, factoring in your tumblehome complications, if any? You wouldn’t want it underwater when you’re swamped.

Wat ah’ done…

– Last Updated: Jul-12-11 7:05 PM EST –


An' then watch de movin' pictoor right after.

Ah' jus' tuck dem out o' de way under de lacin' ta transport on de car.


stern exit
I’ve also seen pumps exit at the stern in the center. Aesthetically, that seemed to me to be the best place.

stern exit is aesthetically optimal
… but functionally deficient. That’s a lot of water left in the tube that will backwash into the hull after you turn the switch off.

stern exit
Wont water in any hose backflow into the boat? The shorter the hose, the less the backflowing water. A backflow valve would keep it in the hose. Not sure that is much better.

I’d use Elmo’s method over drilling - why punch a big hole when the gunwale is a few inches away? Besides they look cool, like canoe-mounted JATO units.

advantages and disadvantages

Advantage over the gunnel: Cheap, easy, non-commital

Advantage Through the hull: Cleaner looking, does not interfere with racks during transport, does not get torn up during a nasty upside down swim (don’t ask how I know)